Sub-Thick Electrodes with Enhanced Transport Kinetics via In Situ Epitaxial Heterogeneous Interfaces for High Areal-Capacity Lithium Ion Batteries

Double-emulsion synthesis of reactive epoxy nanospheres for advanced lithium-ion battery binders

The rapid advancement of electric vehicles imposes significant challenges on lithium-ion battery (LIBs) technology. Polymer binders offer a promising low-cost solution. However, for anode materials, the conventional styrene butadiene latex/carboxymethyl cellulose (SBR/CMC) binders exhibit inherent issues, including binder flotation during solvent evaporation and undesired film formation on anode surfaces. Herein, ultra-small reactive epoxy nanospheres (EPS, 70 nm) were successfully synthesized using a customized double emulsion (DE) demulsification method. The structural design of the internal water phase, two consecutive emulsifications and an innovative phase inversion strategy are crucial to achieve ultra-small particle size. By eliminating the binder migration phenomenon and establishing a covalent cross-linked network within the electrode, the EPS bonded electrode achieved a peel strength of 7.03 N cm-1, surpassing the 4.53 N cm-1 observed in the SBR bonded electrode. Furthermore, EPS can optimize the electrode pore structure and increase the electrode's wettability to the electrolyte, thereby improving the electrode rate performance. At a current density of 10C, the EPS bonded electrode achieved a capacity retention of 50.4 %, which is much higher than that of the SBR bonded electrode (21.2 %). Consequently, reactive EPS presents an effective way to enhance the overall performance of LIBs through the strategic design of polymer binders.

Natural Pitch-Derived Carbon Networks Induced Lattice Strain Engineering in Nickel-Based Heterostructures Enables Efficient Anodes for Sodium-Ion Batteries

The development of high-performance sodium-ion batteries (SIBs) relies on enhancing the electrochemical properties of the electrodes, particularly the transition metal compounds (TMCs) through effective carbon coatings. Herein, a straightforward approach using polymerized natural pitch-derived carbon (PNPC) via step-growth polymerization regulates the lattice strain in Ni3S2-NiO heterostructures (NSNO) on nickel foam (NF). This method replaces the complex multistep carbon coatings with a cost-effective liquid-phase application of PNPC, followed by pyrolysis to create PNPC@NSNO/NF. Comparative analysis shows that PNPC effectively modulates lattice strain, achieving 3.50% tensile strain compared to 5.60% for non-polymerized carbon. The optimized PNPC@NSNO/NF electrode exhibits exceptional high areal capacity of 2.72 mAh cm-2@1 mA cm-2, impressive rate capability, and 97.28% capacity retention after 200 cycles. The enhanced contact area and electrical conductivity provided by the PNPC improve charge transfer kinetics and overall performance. Theoretical analyses confirm that the PNPC@NSNO/NF electrode with 3.50% lattice strain lowers the Na⁺ diffusion barrier, enhances charge transfer, and improves charge distribution, boosting the electrode performance. This work establishes a straightforward method for synthesizing lattice-strained SIB anodes, highlighting its potential for advancing SIB technology.

Hollow tubular sea-urchin structure with high catalytic activity of NiCo2Se4@CS2 cathodes for high-performance Al/S batteries

The shuttle effect of aluminum polysulfides (AlPSs) have been a source of concern for studying Al/S batteries. Due to the weak adsorption of CS composites, research on cathode materials for Al/S batteries has been delayed. As it is generally known that Al2S3 decomposition demands a large Gibbs free energy, this work has tried to reduce the Al2S3 decomposition potential energy. Herein, the Ni/Co bimetallic selenide reduces the energy barrier conversion and mitigates the polarization effects, while morphology control enables the storage and anchoring of S, alleviating the shuttle effect. Additionally, the intermediate products serve as single-atom catalysts, increasing the active sites, synergistically enhancing the ion diffusion kinetics. DFT calculations verify that NiCo2Se4 has a moderate Gibbs free energy change during the rate-limiting step of S reduction and the most robust adsorption energy to Al2S3. NiCo2Se4@CS2/Al has a remaining capacity of 135 mAh/g after 450 cycles (at 200 mA g-1), pioneering novel ideas for the development of Al/S batteries.

Supramolecular channels via crown ether functionalized polyaniline for proton-self-doped cathode in aqueous zinc-ion battery

Polyaniline (PANI) has been widely used as a cathode in aqueous zinc-ion batteries (AZIBs) because of its attractive conductivity and energy storage capability. However, the extensive application of PANI is limited by spontaneous deprotonation and slow diffusion kinetics. Herein, an 18-crown-6-functionalised PANI pseudorotaxane (18C6@PANI) cathode is successfully developed through a facile template-directed polymerisation reaction. The 18C6@PANI cathode exhibits a high specific capacity of 256 mAh g-1 at 0.2 A/g, excellent rate performance of 134 mAh g-1 at 6 A/g and outstanding cycle stability at a high current density of 3 A/g over 10,000 cycles. Experimental and theoretical analyses demonstrate the formation of the -N-Zn-O- structure. The abundant supramolecular channels in pseudorotaxane, induced by crown ether functional groups, are beneficial for achieving superior cyclability and rate capability. These encouraging results highlight the potential for designing more efficient PANI-based cathodes for high-performance AZIBs.

Flexible free-standing Fe-CoP-NAs/CC nanoarrays for high-performance full lithium-ion batteries

In this study, a flexible, free-standing Fe-doped CoP nanoarrays electrode for superior lithium-ion storage has been successfully fabricated. The electrode combines the advantages of a Fe-doping and a flexible carbon cloth (CC) support, resulting in a high specific capacity (1356 mAh/g at 0.2 A/g) and excellent cycling stability (1138 mAh/g after 100 cycles). The cyclic voltammetry (CV) curves at different scan rates investigate the outstanding lithium storage behavior of Fe-CoP-NAs/CC which indicates a combined influence of diffusion behavior and capacitance behavior on the electrochemical process. The galvanostatic intermittent titration technique (GITT) analyzes the diffusion kinetics of Li+ which indicates the fast diffusion kinetics in the Fe-CoP/NAs/CC anode. The assembled Fe-CoP-NAs/CC//LiFePO4 battery exhibits a remarkable capacity of 325.2 mAh/g even at 5 A/g. And the battery also has good cycle stability, and still provides 498.1 mAh/g specific capacity after 200 cycles. Moreover, the Fe-CoP-NAs/CC//LiFePO4 soft-pack battery can continuously power the LEDs when it is bent at various angles which demonstrates its potential for use in wearable devices.

Heterointerfaces: Unlocking Superior Capacity and Rapid Mass Transfer Dynamics in Energy Storage Electrodes

Heterogeneous electrode materials possess abundant heterointerfaces with a localized "space charge effect", which enhances capacity output and accelerates mass/charge transfer dynamics in energy storage devices (ESDs). These promising features open new possibilities for demanding applications such as electric vehicles, grid energy storage, and portable electronics. However, the fundamental principles and working mechanisms that govern heterointerfaces are not yet fully understood, impeding the rational design of electrode materials. In this study, the heterointerface evolution during charging and discharging process as well as the intricate interaction between heterointerfaces and charge/mass transport phenomena, is systematically discussed. Guidelines along with feasible strategies for engineering structural heterointerfaces to address specific challenges encountered in various application scenarios, are also provided. This review offers innovative solutions for the development of heterogeneous electrode materials, enabling more efficient energy storage beyond conventional electrochemistry. Furthermore, it provides fresh insights into the advancement of clean energy conversion and storage technologies. This review contributes to the knowledge and understanding of heterointerfaces, paving the way for the design and optimization of next-generation energy storage materials for a sustainable future.

Constructed Mott-Schottky Heterostructure Catalyst to Trigger Interface Disturbance and Manipulate Redox Kinetics in Li-O2 Battery

Lithium-oxygen batteries (LOBs) with high energy density are a promising advanced energy storage technology. However, the slow cathodic redox kinetics during cycling causes the discharge products to fail to decompose in time, resulting in large polarization and battery failure in a short time. Therefore, a self-supporting interconnected nanosheet array network NiCo2O4/MnO2 with a Mott-Schottky heterostructure on titanium paper (TP-NCO/MO) is ingeniously designed as an efficient cathode catalyst material for LOBs. This heterostructure can accelerate electron transfer and influence the charge transfer process during adsorption of intermediate by triggering the interface disturbance at the heterogeneous interface, thus accelerating oxygen reduction and oxygen evolution kinetics and regulating product decomposition, which is expected to solve the above problems. The meticulously designed unique structural advantages enable the TP-NCO/MO cathode catalyst to exhibit an astounding ultra-long cycle life of 800 cycles and an extraordinarily low overpotential of 0.73 V. This study utilizes a simple method to cleverly regulate the morphology of the discharge products by constructing a Mott-Schottky heterostructure, providing important reference for the design of efficient catalysts aimed at optimizing the adsorption of reaction intermediates.

Binder-Free Intertwined Si and MnO2 Composite Electrode for High-Performance Li-Ion Battery Anode

Silicon is considered as the most felicitous anode material candidate for lithium-ion batteries on account of abundant availability, suitable operating potential, and high specific capacity. Nevertheless, drastic volume expansion during the cycle impedes its practical utilization. Herein, Si and MnO2 (Si-MO) constructed the binder-free intertwined electrode that is reported to effectively improve upon the cycling stability of Si-based materials. The Si-based electrode without a binder has good electrical conductivity, strong adhesion to the substrate, and ample space for mitigating volume expansion. The incorporation of MnO2 establishes a multiphase interface, which mitigates the electrode volume expansion, and supports the electrode structure. Furthermore, MnO2 (∼1230 mAh g-1 theoretical capacity) synergistically enhances the overall capacity of the composite electrodes. Consequently, the Si-MO composite electrode exhibits a reversible specific capacity of 1300 mAh g-1 at 420 mA g-1 and remarkable cycling performance with a specific capacity of 830 mAh g-1 after 500 cycles. In particular, a reversible specific capacity of 837 mAh g-1 at 4200 mA g-1 is achieved and remains stable during 200 cycles. This work provides a potentially feasible way to achieve the Si-based anode commercialization for LIBs.

Metal Organic Frameworks as Polysulfide Reaction Modulators for Lithium Sulfur Batteries: Advances and Perspectives

Currently, lithium sulfur (Li-S) battery with high theoretical energy density has attracted great research interest. However, the diffusion and loss process of intermediate lithium polysulfide during charge-discharge hindered the application of the Li-S battery in modern life. To overcome this issue, metal organic frameworks (MOFs) and their composites have been regarded as effective additions to restrain the LiPS diffusion process for Li-S battery. Benefiting from the unique structure with rich active sites to adsorb LiPS and accelerate the LiPS redox, the Li-S batteries with MOFs modified exhibit superior electrochemical performance. Considering the rapid development of MOFs in Li-S battery, this review summarizes the recent studies of MOFs and their composites as the sulfur host materials, functional interlayer, separator coating layer, and separator/solid electrolyte for Li-S batteries in detail. In addition, the promising design strategies of functional MOF materials are proposed to improve the electrochemical performance of Li-S battery.

Cation-induced Ti3C2Tx MXene@melamine sponge aerogels with large layer spacing and high strength for high-performance supercapacitors

The self-assembled aerogels are considered as an efficient strategy to address the aggregation and restacking of Ti3C2Tx MXene nanosheets for high-performance supercapacitors. However, the low mechanical strength of the MXene aerogel results in the structural collapse of the self-standing supercapacitor electrode materials. Herein, a low-cost melamine sponge (MS) absorbed different cations (H+, K+, Mg2+, Fe2+, Co2+, Ni2+ and Al3+), serves as a carrier and crosslinker for loading MXene hydrogel induced by the absorbed cations on the skeleton surface and the pores of MS, resulting in the high loading mass MXene aerogels with high mechanical strength. The experimental results show that the Mg-Ti3C2Tx@MS aerogel exhibits the maximum area capacitance of 702.22 mF cm-2 at 3 mA cm-2, and the area capacitance is still 603.12 mF cm-2 even at 100 mA cm-2, indicating the high rate capability with a capacitance retention of 85.89 %. It is worth noting that the constructed asymmetric supercapacitor with activated carbon achieves high energy densities of 104.53 μWh cm-2 and 93.87 μWh cm-2 at 800 μW cm-2 and 7999 μW cm-2, respectively. Furthermore, the asymmetric supercapacitor shows the high cycling stability with 90.2 % capacity retention after 10,000 cycles. This work provides a feasible strategy to prepare Ti3C2Tx MXene aerogels with large layer spacing and high strength for high-performance supercapacitors.

Directional Polarization of a Ferroelectric Intermediate Layer Inspires a Built-In Field in Si Anodes to Regulate Li+ Transport Behaviors in Particles and Electrolyte

The silicon (Si) anode is prone to forming a high electric field gradient and concentration gradient on the electrode surface under high-rate conditions, which may destroy the surface structure and decrease cycling stability. In this study, a ferroelectric (BaTiO3) interlayer and field polarization treatment are introduced to set up a built-in field, which optimizes the transport mechanisms of Li+ in solid and liquid phases and thus enhances the rate performance and cycling stability of Si anodes. Also, a fast discharging and slow charging phenomenon is observed in a half-cell with a high reversible capacity of 1500.8 mAh g-1 when controlling the polarization direction of the interlayer, which means a fast charging and slow discharging property in a full battery and thus is valuable for potential applications in commercial batteries. Simulation results demonstrated that the built-in field plays a key role in regulating the Li+ concentration distribution in the electrolyte and the Li+ diffusion behavior inside particles, leading to more uniform Li+ diffusion from local high-concentration sites to surrounding regions. The assembled lithium-ion battery with a BaTiO3 interlayer exhibited superior electrochemical performance and long-term cycling life (915.6 mAh g-1 after 300 cycles at a high current density of 4.2 A g-1). The significance of this research lies in exploring a new approach to improve the performance of lithium-ion batteries and providing new ideas and pathways for addressing the challenges faced by Si-based anodes.

Surface design for high ion flux separator in lithium-sulfur batteries

Addressing the shuttle effect is a critical challenge in realizing practical applications of lithium-sulfur batteries. One promising avenue refers to the surface modification of separators, transitioning them from closed to open structures. In the current investigation, a high ion flux separator was devised by means of MnO2 self-assembly onto a Porous Polypropylene (PP) separator, subsequently coupling it with biochar. The separator exhibited favorable ion and electronic conductivity. Moreover, it adeptly captured and transformed polysulfides into Li2S2/Li2S, cyclically curbing the mobility of Polysulfide lithium (LiPSs). In addition, this augmentation in the kinetic conversion of LiPSs during the electrochemical process translated into an impressive discharge specific capacity and area capacity of 939 mAh/g and 4 mAh cm-2, respectively. Moreover, this innovative design methodology provides an alternative avenue for future separator designs within lithium-sulfur batteries.

Organic Species-Intercalated Vanadium Oxide for Sodium-Ion Battery: Mixed-Anion Coordination Effect, Enhanced d-p Orbital Hybridization, and Topotactic Phase Conversion Induced by N-Substitution

Sodium-ion battery (SIB) is a reasonable alternative to lithium-ion battery (LIB) in the field of grid-scale energy storage systems. Unfortunately, the development of appropriate cathode material is a bottleneck in the field of SIB. In the present work, (p-TQ)-VO, formulated as (p-TQ)0.2V2O5·0.38H2O, was synthesized based on a facile hydrothermal reaction of V2O5 and methylhydroquinone (p-HTQ). And when V2O5 was replaced by VN, (p-TQ)-VN, formulated as (p-TQ)0.22V2(O/N)5, was prepared instead. The (p-TQ)-VO sample displays good electrochemical performance as the SIB cathode. And (p-TQ)-VN shows a much higher capacity at a small current density, and it can maintain structural integrity with partial topotactic phase transformation into NaxV2O5 during the discharge/charge process. A series of characterizations of (p-TQ)-VO and (p-TQ)-VN reveals the successful intercalation of p-TQ into the layered V2O5 with a (001) lattice spacing of 13.7 and 10.7 Å, respectively. In (p-TQ)-VN, partial terminal oxygen (Ot) atoms from the V-O-V layer have been substituted by N atoms, which can boost the orbital hybridization of V 3d and Ot 2p, shorten the V-Ot bonds in the c-axial direction, and elongate the V-O bonds in the ab plane with compressed {VO4N2} octahedra, giving rise to mixed-anion coordination effect. As a result, the enhanced electron densities around the Ot atoms of the V-O-V layer can facilitate the affinity toward the inserted Na+ ions, leading to partial phase conversion into NaNO2/NaNO3. Moreover, density functional density (DFT) calculations reveal that the N-incorporation can improve electron conductivity with richer molecular orbital energy levels, resulting in multistep redox reactions and enhanced capacity.

Metal-organic frameworks-derived MCo2O4 (M = Zn, Ni, Cu) two-dimensional nanosheets as anodes materials to boost lithium storage

Transition metal oxides (TMOs) have received significant consideration. Because of their enormous theoretical capacity, cheap, and less toxicity. Notably, cobalt-based materials hold promises as negative electrode materials for batteries, but they suffer from less electrical conductivity and significant volume changes during operation. In order to address these challenges, sacrificial templating techniques at the nanoscale offer a potential solution for improving the electrochemical stability and rate performance of these materials. More specifically, these tactics have proven popular for designing Li-ion storages. To ascertain the impact of multiple metal ions on the electrochemical capacity, metal organic frameworks (MOFs) derived MCo2O4-MOF (M = Zn, Ni, Cu) were developed. Among these, ZnCo2O4 showed the best electrochemical performance (927.2 mAh g-1 at 0.1 A g-1 after 250 cycles). Furthermore, calculations based on density functional theory (DFT) revealed that ZnCo2O4 had the lowest Li+ adsorption energy, with a minimum value of -1.61 eV. Moreover, this research aims to design controllable nanostructures in order to enhance the design of transition bimetallic oxide composites for energy storage applications.

Surfactant regulated Core-Double-Shell NF@NiO nanosheets matrix as integrated anodes for Lithium-Ion batteries

The direct oxidation of three-dimensional nickel foam (3D NF) to nickel oxide (NiO) as integrated anode material for lithium-ion batteries (LIBs) has attracted significant attention towards achieving high-areal-capacity and high-energy density LIBs. However, the rate capability of such monolithic NiO in LIBs usually falls off rapidly due to the poor electrical conductivity that hindered its ionic transport kinetics. Herein, to ease the ionic transport constrains, a surfactant-regulated strategy is developed for preparing in-situ core-double-shell architecture that consists of core nickel skeleton, dense nickel oxide shell and porous nickel oxide nanosheets (NS) shell as anode materials for LIBs. Among the three employed surfactants including cationic surfactant, anionic surfactant and nonionic surfactant, the anionic surfactant (sodium dodecyl sulfate, SDS) modulated anode denoted SDS-NF@NiONS exhibits ultrahigh reversible areal capacity of 8.64 mAh cm-2@ 0.4 mA cm-2, and excellent rate areal capacity of 5.20 mAh cm-2 @ 3.0 mA cm-2, which did not only show the best ever reported NiO-based high-areal-capacity based electrodes, but also demonstrate impressive performance in practical full cell LIBs. In addition, in-situ Raman and kinetic analyses confirm the mechanism of Li-ion storage and facile ionic transport kinetics in this proposed design.

Mass Loading-Independent Lithium Storage of Transitional Metal Compounds Achieved by Multi-Dimensional Synergistic Nanoarchitecture

Nanostructured transitional metal compounds (TMCs) have demonstrated extraordinary promise for high-efficient and rapid lithium storage. However, good performance is usually limited to electrodes with low mass loading (≤1.0 mg cm-2 ) and is difficult to realize at higher mass loading due to increased electrons/ions transport limitations in the thicker electrode. Herein, the multi-dimensional synergistic nanoarchitecture design of graphene-wrapped MnO@carbon microcapsules (capsule-like MnO@C-G) is reported, which demonstrates impressive mass loading-independent lithium storage properties. Highly porous MnO nanoclusters assembled by 0D nanocrystals facilitate sufficient electrolyte infiltration and shorten the solid-state ions transport path. 1D carbon shell, 2D graphene, and 3D continuous network with tight interconnection accelerate electrons transport inside the thick electrode. The capsule-like MnO@C-G delivers ultrahigh gravimetric capacity retention of 91.0% as the mass loading increases 4.3 times, while the areal capacities increase linearly with the mass loading at various current densities. Specifically, the capsule-like MnO@C electrode delivers a remarkable areal capacity of 2.0 mAh cm-2 at a mass loading of 3.0 mg cm-2 . Moreover, the capsule-like MnO@C also demonstrates excellent performance in full battery applications. This study demonstrates the effectiveness of multi-dimensional synergistic nanoarchitecture in achieving mass loading-independent performance, which can be extended to other TMCs for electrochemical energy storage.

Two Birds with One Stone: Micro/Nanostructured SiOx Cy Composites for Stable Li-Ion and Li Metal Anodes

Developing stable silicon-based and lithium metal anodes still faces many challenges. Designing new highly practical silicon-based anodes with low-volume expansion and high electrical conductivity, and inhibiting lithium dendrite growth are avenues for developing silicon-based and lithium metal anodes, respectively. In this study, SiOx Cy microtubes are synthesized using a chemical vapor deposition method. As Li-ion battery anodes, the as-prepared SiOx Cy not only combines the advantages of nanomaterials and the practical properties of micromaterials, but also exhibits high initial Coulombic efficiency (80.3%), low volume fluctuations (20.4%), and high cyclability (98% capacity retention after 1000 cycles). Furthermore, SiOx Cy , as a lithium deposition substrate, can effectively promote the uniform deposition of metallic lithium. As a result, low nucleation overpotential (only 6.0 mV) and high Coulombic efficiency (≈98.9% after 650 cycles, 1.0 mA cm-2 and 1.0 mAh cm-2 ) are obtained on half cells, as well as small voltage hysteresis (only 9.5 mV, at 1.0 mA cm-2 ) on symmetric cells based on SiOx Cy . Full batteries based on both SiOx Cy and SiOx Cy @Li anodes demonstrate great practicality. This work provides a new perspective for the simultaneous development of practical SiOx Cy and dendrite-free lithium metal anodes.

Hierarchical 3D Electrode Design with High Mass Loading Enabling High-Energy-Density Flexible Lithium-Ion Batteries

Flexible lithium-ion batteries (LIBs) have attracted significant attention owing to their ever-increasing use in flexible and wearable electronic devices. However, the practical application of flexible LIBs in devices has been plagued by the challenge of simultaneously achieving high energy density and high flexibility. Herein, a hierarchical 3D electrode (H3DE) is introduced with high mass loading that can construct highly flexible LIBs with ultrahigh energy density. The H3DE features a bicontinuous structure and the active materials along with conductive agents are uniformly distributed on the 3D framework regardless of the active material type. The bicontinuous electrode/electrolyte integration enables a rapid ion/electron transport, thereby improving the redox kinetics and lowering the internal cell resistance. Moreover, the H3DE exhibits exceptional structural integrity and flexibility during repeated mechanical deformations. Benefiting from the remarkable physicochemical properties, pouch-type flexible LIBs using H3DE demonstrate stable cycling under various bending states, achieving a record-high energy density (438.6 Wh kg-1 and 20.4 mWh cm-2 ), and areal capacity (5.6 mAh cm-2 ), outperforming all previously reported flexible LIBs. This study provides a feasible solution for the preparation of high-energy-density flexible LIBs for various energy storage devices.

Building a Flexible and Highly Ionic Conductive Solid Electrolyte Interphase on the Surface of Si@C Anodes by Binary Electrolyte Additives

Si@C as a high specific capacity anode material for lithium batteries (LIBs) has attracted a lot of attention. However, the severe volume change during lithium de-embedding causes repeated rupture/reconstruction of the solid electrolyte interphase (SEI), resulting in poor cycling stability of the Si-based battery system and thus hindering its application in commercial batteries. Using electrolyte additives to form an excellent SEI is considered to be a cost-effective method to meet this challenge. Here, the classical film-forming additive vinyl carbonate (VC), and the newly emerging lithium salt additive lithium difluorophosphate (LiDFP), are chosen as synergistic additives to improve the electrode-electrolyte interface properties. Final results show that the VC additive generates flexible polycarbonate components at the electrode/electrolyte interface, preventing the fragmentation of Si particles. However, the organic components show high impedance, inhibiting the fast transport of Li+. This defect can be supplemented from the decomposition substances of the LiDFP additive. The derived inorganic products, such as LiF and Li3PO4, can strengthen the reaction kinetics of the electrode, reduce the interfacial impedance, and promote the Li+ transport. Thus, the synergistic effect of VC and LiDFP additives builds an effective SEI with good flexibility and high ionic conductivity and then significantly improves the cycling and rate stability of Si@C anodes. The experimental results show that the utilization of LiDFP and VC additives to modify the Si@C anode interface enhances the capacity retention of the Si@C/Li half-cell after 100 cycles from 68.2% to 85.1%. Besides, the possible mechanism of action between VC and LiDFP is proposed by using the spectral characterization technique and density functional theory (DFT) calculations. This research opens up a new possibility for improvement of SEI, and provides a simple way to achieve high-performance Si-based LIBs.

Si-Based High-Entropy Anode for Lithium-Ion Batteries

Up to now, only a small portion of Si has been utilized in the anode for commercial lithium-ion batteries (LIBs) despite its high energy density. The main challenge of using micron-sized Si anode is the particle crack and pulverization due to the volume expansion during cycling. This work proposes a type of Si-based high-entropy alloy (HEA) materials with high structural stability for the LIB anode. Micron-sized HEA-Si anode can deliver a capacity of 971 mAhg-1 and retains 93.5% of its capacity after 100 cycles. In contrast, the silicon-germanium anode only retains 15% of its capacity after 20 cycles. This study has discovered that including HEA elements in Si-based anode can decrease its anisotropic stress and consequently enhance ductility at discharged state. By utilizing in situ X-ray diffraction and transmission electron microscopy analyses, a high-entropy transition metal doped Lix (Si/Ge) phase is found at lithiated anode, which returns to the pristine HEA phase after delithiation. The reversible lithiation and delithiation process between the HEA phases leads to intrinsic stability during cycling. These findings suggest that incorporating high-entropy modification is a promising approach in designing anode materials toward high-energy density LIBs.

PANI-Coated VOx Nanobelts with Core-Shell Architecture for Flexible All-Solid-State Supercapacitor

As a typical pseudocapacitor material, VOx possesses mixed valence states, making it an ideal electrode material for symmetric screen-printed supercapacitors. However, its high internal resistance and low energy density are the main hurdles to its widespread application. In this study, a two-dimensional PANI@VOx nanobelt with a core-shell architecture was constructed via a two-step route. This strategy involves the preparation of VOx using a solvothermal method, and a subsequent in situ polymerization process of the PANI. By virtue of the synergistic effect between the VOx core and the PANI shell, the optimal VOx@PANI has an enhanced conductivity of 0.7 ± 0.04 S/Ω, which can deliver a high specific capacitance of 347.5 F/g at 0.5 A/g, a decent cycling life of ~72.0%, and an outstanding Coulomb efficiency of ~100% after 5000 cycles at 5 A/g. Moreover, a flexible all-solid-state symmetric supercapacitor (VOx@PANI SSC) with an in-planar interdigitated structure was screen-printed and assembled on a nickel current collector; it yielded a remarkable areal energy density of 115.17 μWh/cm2 at an areal power density of 0.39 mW/cm2, and possessed outstanding flexibility and mechanical performance. Notably, a "Xiaomi" hygrothermograph (3.0 V) was powered easily by tandem SSCs with an operating voltage of 3.1 V. Therefore, this advanced pseudocapacitor material with core-shell architecture opens novel ideas for flexible symmetric supercapacitors in powering portable/wearable products.

Is Soft Carbon a More Suitable Match for SiOx in Li-Ion Battery Anodes?

Silicon oxide (SiOx ), inheriting the high-capacity characteristic of silicon-based materials but possessing superior cycling stability, is a promising anode material for next-generation Li-ion batteries. SiOx is typically applied in combination with graphite (Gr), but the limited cycling durability of the SiOx /Gr composites curtails large-scale applications. In this work, this limited durability is demonstrated in part related to the presence of a bidirectional diffusion at the SiOx /Gr interface, which is driven by their intrinsic working potential differences and the concentration gradients. When Li on the Li-rich surface of SiOx is captured by Gr, the SiOx surface shrinks, hindering further lithiation. The use of soft carbon (SC) instead of Gr can prevent such instability is further demonstrated. The higher working potential of SC avoids bidirectional diffusion and surface compression thus allowing further lithiation. In this scenario, the evolution of the Li concentration gradient in SiOx conforms to its spontaneous lithiation process, benefiting the electrochemical performance. These results highlight the focus on the working potential of carbon as a strategy for rational optimization of SiOx /C composites toward improved battery performance.

Three-dimensional micro-nanostructures based on binary transitional metal sulfides with doped carbon protector enabled high-performance and safe batteries

The lack of suitable Li⁺ reservoirs and the risk of thermal runaway have hindered the extended use of lithium-ion batteries. Although utilizing Li₄Ti₅O₁₂ or TiO₂ can improve the thermal safety, their low theoretical capacities compromise the electrochemical performance of the cell. In this study, a three-dimensional micro-nanostructure based on binary transitional metal sulfides (TMSs) with a doped carbon protector (SnS/Co₉S₈@HC) is designed. When operating at 0.1-1 A g^-1, the SnS/Co₉S₈@HC cell exhibits a high inceptive capacity of 1104.8 mAh g^-1 with a high coulomb efficiency of 97.1%. Even after 1000 cycles, it delivers a relatively-high capacity of 450.3 mAh g^-1, indicating a low capacity decay rate of 0.033% per cycle (from the 2nd to the 1000th cycle). The thermal runaway actions of the cells with graphite and SnS/Co₉S₈@HC anodes are investigated. The results demonstrate that the cell with the SnS/Co₉S₈@HC anode exhibits a significantly reduced maximum thermal runaway temperature of 473.5 ± 6.2℃ and maximum temperature increasing rate of 15.1 ± 0.6 °C min^-1 compared to the graphite cell. This indicates that SnS/Co₉S₈@HC cell holds higher thermal safety. The potential of SnS/Co₉S₈@HC as sodium ion batteries anode is also investigated. The results indicate an initial capacity of 631.7 mAh g^-1, with a low capacity decay rate of 0.063% per cycle when operating at 2 A g^-1. This work may be enlightening for constructing multi-phase TMSs based hierarchical structure towards superior and safe energy storage.

A strontium ferrite modified separator for adsorption and catalytic conversion of polysulfides for excellent lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have emerged as one of the ideal contenders for the upcoming generation of high energy storage devices due to their superb energy density. Nonetheless, the shuttle effect generated by intermediate lithium polysulfides (LiPSs) during cell cycling brings about capacity degradation and poor cycling stability of LSBs. Here, a versatile SrFe₁₂O₁₉ (FSO) and acetylene black (AB) modified PP separator is first presented to inhibit the shuttle effect. Thanks to the strong chemical interaction of Fe and Sr with polysulphides in FSO, it can trap LiPSs and provide catalytic sites for their conversion. Therefore, the cell using the FSO/AB@PP separator has a high initial discharge specific capacity (930 mA h g^-1) at 2 C and lasts for 1000 cycles with a remarkably low fading rate (0.036% per cycle), while those using PE and AB@PP separators have inferior initial specific capacities (255 mA h g^-1 and 652 mA h g^-1, respectively) and fail within 600 cycles. This work proposes a novel approach for addressing the shuttle of LiPSs from a bimetallic oxide modified separator.

High-Voltage and Stable Manganese Hexacyanoferrate/Zinc Batteries Using Gel Electrolytes

Because of the high safety and environmental friendliness, aqueous zinc-ion batteries have gained a lot of attention in recent years. Prussian blue and its analogues are regarded as a promising cathode material of zinc-ion batteries. Manganese hexacyanoferrate is appropriate among them due to its high operating voltage, large capacity, and cheap price. However, the poor cycling stability of manganese hexacyanoferrate, mainly caused by transition metal dissolution, side reaction, and phase transition, greatly restricts its practical application. In this work, gelatin is used to limit the content of free water in the electrolyte, thus reducing the dissolution effect of transition metal manganese. The introduction of gelatin improves the durability of the Zn anode as well. The optimized MnHCF/gel-0.3/Zn battery displays a high reversible capacity (120 mAh·g^-1 at 0.1 A·g^-1), an excellent rate performance (42.7 mAh·g^-1 at 2 A·g^-1), and a good capacity retention (65% at 0.5 A·g^-1 after 1000 cycles).

High-energy-density flexible graphene-based supercapacitors enabled by atypical hydroquinone dimethyl ether

Supercapacitor is an electrochemical energy-storage technology that can meet the green and sustainable energy needs of the future. However, a low energy density was a bottleneck that limited its practical application. To overcome this, we developed a heterojunction system composed of two-dimensional (2D) graphene and hydroquinone dimethyl ether- an atypical redox-active aromatic ether. This heterojunction displayed a large specific capacitance (Cs) of 523 F g^-1 at 1.0 A g^-1, as well as good rate capability and cycling stability. When assembled in symmetric and asymmetric two-electrode configuration, respectively, supercapacitors can work in voltage windows of 0 ∼ 1.0 V and 0 ∼ 1.6 V, accordingly, and exhibited attractive capacitive characteristics. The best device can deliver an energy density of 32.4 Wh Kg^-1 and a power density of 8000 W Kg^-1, and suffered a small capacitance degradation. Additionally, the device showed low self-discharge and leakage current behaviors during long time. This strategy may inspire exploration of aromatic ether electrochemistry and pave a way to develop electrical double-layer capacitance (EDLC)/pseudocapacitance heterojunctions to boost the critical energy density.

Boosting cobalt ditelluride quantum-rods anode materials for excellent potassium-ion storage via hierarchical physicochemical encapsulation

The exploration of anode materials that can store large-sized K-ion to solve the poor kinetics and large volume expansion issues has become the key scientific bottlenecks hindering the development of potassium-ion batteries (PIBs). Herein, ultrafine CoTe₂ quantum rods physiochemically encapsulated by graphene and nitrogen-doped carbon (CoTe₂@rGO@NC) are regarded as anode electrodes for PIBs. Dual physicochemical confinement and quantum size effect not only enhance electrochemical kinetics but also restrain large lattice stress during repeated K-ion insertion/extraction process. Superior electronic conductivity, K-ion adsorption, and diffusion ability can be acquired for CoTe₂@rGO@NC, confirmed through first-principles calculations and kinetics study. K-ion insertion/extraction proceeds via a typical conversion mechanism relying on Co as the redox site, where the robust chemical bond of COCo plays an important role in maintaining the electrode stability. Accordingly, CoTe₂@rGO@NC contributes a high initial capacity of 237.6 mAh·g^-1 at 200 mA·g^-1, a long lifetime over 500 cycles with low-capacity decay of 0.10% per cycle. This research will lay the materials science foundation for the construction of quantum-rod electrodes.

Rational design of NiO/NiSe2@C heterostructure as high-performance anode for Li-ion battery

Biphasic or multiphase heterostructures have promising futures in advanced electrode materials for energy-related applications because of their desirable synergistic effects. Here we prepared a rational NiO/NiSe₂@C heterostructure microsphere through carbonization, selenization, and oxidation using Ni-MOF as a precursor. Electrochemical studies were conducted to examine the Li⁺ storage characteristics, and density functional theory (DFT) was utilized to comprehend the underlying mechanism. When employed as the anode for LIBs, the NiO/NiSe₂@C showed a high specific capacity and long-term cyclic stability, with a specific capacity of 992 mAh g^-1 for 600 cycles at a current density of 0.2 A g^-1. The NiO/NiSe₂@C exhibits a significantly enhanced lithium-ion diffusion coefficient ( [Formula: see text] ) value. The DFT results show that an electron-rich area forms at the NiO/NiSe₂ heterointerface, where the metalloid selenium transfers electrons to the oxygen atoms. The lithiation reactions were improved dramatically by redistributing interfacial charges, which can trigger a built-in electric field that dramatically promotes the capacitance contribution of electrode materials, enhances the lithium storage capacity, and accelerates the ion/electron transmission. The rational synthesis of NiO/NiSe₂@C heterostructure can provide an idea for designing novel heterostructure anode materials.

Chitosan modulated engineer tin dioxide nanoparticles well dispersed by reduced graphene oxide for high and stable lithium-ion storage

Tin based materials are widely investigated as a potential anode material for lithium-ion batteries. Effectively dispersing SnO₂ nanocrystals in carbonaceous supporting skeleton using simplified methods is both promising and challenging. In this work, water soluble chitosan (CS) chains are employed to modulate the redox coprecipitation reaction between stannous chloride (SnCl₂) and few-layered graphene oxide (GO), where the excessive restacking of the corresponding reduced graphene oxide sheets (RGO) has been effectively inhibited and the grain size of the in-situ formed SnO₂ nanoparticles have been significantly controlled. In particular, the CS molecules are gradually detached from the RGO sheets with the GO deoxygenation process, leaving only a small quantity of CS remnants in the intermediate SnO₂@CS@RGO sample. The final SnO₂/CSC/RGO sample with significantly improved microstructure is synthesized after a simple thermal treatment, which delivers a high specific capacity of 842.9 mAh g^-1 at 1000 mA·g^-1 for 1000 cycles in half cells and a specific capacity of 410.5 mAh g^-1 at 200 mA·g^-1 for 100 cycles in full cells. The reasons for the good lithium-ion storage performances for the SnO₂/CSC/RGO composite have been studied.

Tailored engineering of Fe3O4 and reduced graphene oxide coupled architecture to realize the full potential as electrode materials for lithium-ion batteries

Developing advanced electrode materials with appropriate compositions and exquisite configurations is crucial in fabricating lithium-ion batteries (LIBs) with high energy density and fast charging capability plateau. Herein, a Fe₃O₄@reduced graphene oxide (Fe₃O₄@rGO) coupled architecture was rationally designed and in-situ synthesized. Monodispersed mesoporous Fe₃O₄ nanospheres were homogeneously formed and strongly bound on interconnected macroporous rGO frameworks to form well-defined three-dimensional (3D) hierarchical porous morphologies. This tailored Fe₃O₄@rGO coupled architecture fully exploited the advantages of Fe₃O₄ and rGO to overcome their inherent challenges, including spontaneous aggregating/excessive restacking tendency, sluggish ions diffusion/electrons transportation, and severe volume expansion/structural collapse. Benefitting from their synergistic effects, the optimized Fe₃O₄@rGO composite electrode exhibited an improved electrochemical reactivity, electrical conductivity, electrolyte accessibility, and structural stability. The optimized composite electrode displayed a high specific capacity of 1296.8 mA h g^-1 at 0.1 A g^-1 after 100 cycles, even retaining 555.1 mA h g^-1 at 2 A g^-1 after 2000 cycles. The electrochemical kinetics analysis revealed the predominantly pseudocapacitive behaviors of the Fe₃O₄@rGO heterogeneous interfaces, accounting for the excellent electrode performance. This study proposes a viable strategy for use in engineering hybrid composites with coupled architectures to optimize their potential as high-performance electrode materials for use in LIBs.

Emerging 2D Copper-Based Materials for Energy Storage and Conversion: A Review and Perspective

2D materials have shown great potential as electrode materials that determine the performance of a range of electrochemical energy technologies. Among these, 2D copper-based materials, such as Cu-O, Cu-S, Cu-Se, Cu-N, and Cu-P, have attracted tremendous research interest, because of the combination of remarkable properties, such as low cost, excellent chemical stability, facile fabrication, and significant electrochemical properties. Herein, the recent advances in the emerging 2D copper-based materials are summarized. A brief summary of the crystal structures and synthetic methods is started, and innovative strategies for improving electrochemical performances of 2D copper-based materials are described in detail through defect engineering, heterostructure construction, and surface functionalization. Furthermore, their state-of-the-art applications in electrochemical energy storage including supercapacitors (SCs), alkali (Li, Na, and K)-ion batteries, multivalent metal (Mg and Al)-ion batteries, and hybrid Mg/Li-ion batteries are described. In addition, the electrocatalysis applications of 2D copper-based materials in metal-air batteries, water-splitting, and CO₂ reduction reaction (CO₂ RR) are also discussed. This review also discusses the charge storage mechanisms of 2D copper-based materials by various advanced characterization techniques. The review with a perspective of the current challenges and research outlook of such 2D copper-based materials for high-performance energy storage and conversion applications is concluded.

A 3D structure C/Si/ZnCo2O4/CC anode for flexible lithium-ion batteries with high capacity and fast charging ability

ZnCo₂O₄ has attracted extensive attention as a bimetallic transition metal oxide anode material for lithium-ion batteries (LIBs) with high capacity. However, there is still a long way to go to meet the increasing demand for commercial batteries due to their modest conductivity and unobtrusive cycling stability. The use of finely controlled nanostructures and combination with other anode materials are the two main ways to improve the battery performance of ZnCo₂O₄. Herein, ZnCo₂O₄ (ZCO) nanosheets were in situ grown on carbon cloth (CC) through a facile solution method. Si was coated onto the ZCO nanosheet arrays by the magnetron sputtering method (SCZO/CC) to acheive the capacity increase. A layer of C was further coated onto SZCO/CC to improve the electrical conductivity of the whole electrode and to protect the SZCO nanostructure. The obtained CSZCO/CC electrode exhibits a high reversible areal capacity of 1.16 mA h cm^-2 at 5 mA cm^-2 after 500 cycles. At an ultra-high current density of 10 mA cm^-2, the CSZCO/CC electrode can still present a capacity of 0.38 mA h cm^-2 and maintain a capacity retention of 88.4% for 2000 cycles. In situ Raman spectroscopy was used to study the relationship between the electrochemical performance and structure of the electrode materials. The carbon cloth was found to have contributed a nonnegligible part of the capacity of the electrode.

Heterostructures Stimulate Electric-Field to Facilitate Optimal Zn2+ Intercalation in MoS2 Cathode

The electric-field effect is an important factor to enhance the charge diffusion and transfer kinetics of interfacial electrode materials. Herein, by designing a heterojunction, the influence of the electric-field effect on the kinetics of the MoS₂ as cathode materials for aqueous Zn-ion batteries (AZIBs) is deeply investigated. The hybrid heterojunction is developed by hydrothermal growth of MoS₂ nanosheets on robust titanium-based transition metal compound ([titanium nitride, TiN] and [titanium oxide, TiO₂ ]) nanowires, denoted TNC@MoS₂ and TOC@MoS₂ NWS, respectively. Benefiting from the heterostructure architecture and electric-field effect, the TNC@MoS₂ electrodes exhibit an impressive rate performance of 200 mAh g^-1 at 50 mA g^-1 and cycling stability over 3000 cycles. Theoretical studies reveal that the hybrid architecture exhibits a large-scale electric-field effect at the interface between TiN and MoS₂ , enhances the adsorption energy of Zn-ions, and increases their charge transfer, which leads to accelerated diffusion kinetics. In addition, the electric-field effect can also be effectively applied to TiO₂ and MoS₂ , confirming that the concept of heterostructures stimulating electric-field can provide a relevant understanding for the architecture of other cathode materials for AZIBs and beyond.

Regulating the Electronic Configuration of Spinel Zinc Manganate Derived from Metal-Organic Frameworks: Controlled Synthesis and Application in Anode Materials for Lithium-Ion Batteries

In recent years, transition metal oxides have been considered as the most promising anode materials due to their high theoretical capacity, low price, and abundant natural reserves. Among them, zinc manganate is used as an electrode material for anodes, whose application is mostly hindered due to its poor ionic/electronic conductivity. In this work, a series of ZnMn₂O₄ (ZMO) are synthesized by a hydrothermal technique coordinated with a metal-organic framework-based high-temperature calcination process for their application as an anode in lithium-ion batteries (LIBs). Meanwhile, this study systematically explores the influence of carbon doping and the types of organic ligands and oxygen vacancies on the electrochemical properties of the synthesized ZMO. Density functional theory (DFT) calculations and experimental investigations reveal that the introduction of carbon and oxygen vacancies can enhance electronic conductivity, more active sites and faster Li⁺ adsorption, resulting in better electrochemical performances. As expected, all ZMOs with carbon doping (PMA-ZMO, MI-ZMO, and BDC-ZMO) derived from 1,2,4,5-benzenetetracarboxylic acid, 2-methylimidazole, and 1,4-dicarboxybenzene achieve outstanding electrochemical performance. Meanwhile, the introduction of oxygen vacancies can enhance the electronic conductivity and can significantly reduce the activation energy of Li⁺ transport, thereby accelerating the Li⁺ diffusion kinetics in the lithiation/delithiation process. Furthermore, an optimal ZMO anode material synthesized by 2-methylimidazole delivers a high reversible capacity of 1174.7 mA h g^-1 after 300 cycles at 0.1 A g^-1 and 600 mA h g^-1 at 0.5 A g^-1 after 300 cycles. After high-rate charge and discharge cycles, the specific capacity rapidly recovers to a value greater than the initial value, which proves the unusual activation and thereby an excellent rate property of the electrode. Hence, we conclude that ZMO provides potential application prospects as an anode electrode material for LIBs.

Topology Optimized Prelithiated SiO Anode Materials for Lithium-Ion Batteries

Silicon monoxide (SiO)-based materials have great potential as high-capacity anode materials for lithium-ion batteries. However, they suffer from a low initial coulombic efficiency (ICE) and poor cycle stability, which prevent their successful implementation into commercial lithium-ion batteries. Despite considerable efforts in recent decades, their low ICE and poor cycle stability cannot be resolved at the same time. Here, it is demonstrated that the topological optimization of the prelithiated SiO materials is highly effective in improving both ICE and capacity retention. Laser-assisted atom probe tomography combined with thermogravimetry and differential scanning calorimetry reveals that two exothermic reactions related to microstructural evolution are key in optimizing the domain size of the Si active phase and Li₂ SiO₃ buffer phase, and their topological arrangements in prelithiated SiO materials. The optimized prelithiated SiO, heat-treated at 650 °C, shows higher capacity retention of 73.4% and lower thickness changes of 68% after 300 cycles than those treated at other temperatures, with high ICE of ≈90% and reversible capacity of 1164 mAh g^-1 . Such excellent electrochemical properties of the prelithiated SiO electrode originate from its optimized topological arrangement of active Si phase and Li₂ SiO₃ inactive buffer phase.

Electronic synergy to boost the performance of NiCoP-NWs@FeCoP-NSs anodes for flexible lithium-ion batteries

Research and development of flexible lithium-ion batteries (LIBs) with high energy density and long cycle life for portable and wearable electronic devices has been a cutting-edge effort in recent years. In this paper, a novel flexible self-standing anode for LIBs is fabricated successfully, in which NiCoP nanowires (NWs) coated with FeCoP nanosheets (NSs) to form core-shell heterostructure arrays are grown on carbon cloth (CC) (designated as NiCoP-NWs@FeCoP-NSs/CC). The obtained NiCoP-NWs@FeCoP-NSs/CC anode integrates the merits of the one-dimensional (1D) NiCoP-NW core and two-dimensional (2D) FeCoP-NS shell and the CC to show a high lithium-ion storage capacity with long-term cycling stability (1172.6 mA h g^-1 at 1 A g^-1 up to 300 cycles with a capacity retention of 92.6%). The kinetics studies demonstrate that the pseudocapacitive behavior dominates the fast lithium storage of this anode material. For fundamental mechanistic understanding, density functional theory (DFT) analysis is carried out, and manifests that electronic synergy can boost the superior performance of the NiCoP-NWs@FeCoP-NSs/CC anode. The assembled LiFePO₄//NiCoP-NWs@FeCoP-NSs/CC full battery gives a discharge capacity of 469.9 mA h g^-1 at 0.5 A g^-1 after 500 cycles, and even at 2 A g^-1, it still can retain 581.5 mA h g^-1. Besides, the soft pack full battery can keep the LED lit continuously when it is folded at different angles and maintain brightness for a period of time, highlighting the large application potential of this flexible LIB for wearable electronic devices. This work provides an idea for the design and construction of advanced metal phosphide flexible electrodes for LIBs.

Prussian blue analogue/KB-derived Ni/Co/KB composite as a superior adsorption-catalysis separator modification material for Li-S batteries

Lithium‑sulfur batteries (LSBs) are gradually replacing conventional lithium-ion batteries (LIBs), credited to their high theoretical capacity, low cost, and non-toxicity. Nevertheless, the substantial capacity degradation caused by the polysulfide shuttling during charging and discharging has seriously hindered the commercialization of LSBs. Separator modification with functionalized carbon materials has been found to catalyze the breakdown of polysulfides, thereby improving the efficiency of LSBs. Herein, we synthesized Ni/Co-PBAs with KB structures to subsequently derive Ni/Co/KB composites by a carbonization process, which were later used as a modifier layer on the barrier in LSBs in order to effectively alleviate the shuttle problem. The capacity of the Ni/Co/KB composite decorated separator is found to be 1032 mAh/g at 0.5 C with a coulombic efficiency closer to 100%. In the long-term cycling capability evaluation, the initial cycle is approximately 802.9 mAh/g at 1 C, while capacity retention after 400 cycles is also 678.8 mAh/g, with a high-capacity retention rate of 84.5%. The potential of these composites as modifying materials for superior LSBs separators is verified by experimental and theoretical methods.

Carbon Uniformly Distributed SiOx/C Composite with Excellent Structure Stability for High Performance Lithium-Ion Batteries

Silicon oxides (SiOx, 0<x<2) has been considered as one of the most promising candidate materials for high specific energy anode materials and attracted extensive attention. However, there are still some shortcomings within SiOx that extremely limit its promotion in industry, especially the large volume expansion and poor conductivity. Reasonable design of silicon oxides (SiOx) electrode material is very important to improve its energy storage performance. Here, we fabricated a novel porous SiOx/C nanohybrids based on the facile sol-gel method followed by pyrolysis, in which carbon and SiOx not only exhibited uniform distribution at the nanoscale, the stability of SiOx/C network can also be easily adjusted via controlling the hydrolysis and condensation rate of precursors in situ. Thanks to the excellent electrical conductivity and structural stability of carbon, uniform distribution of SiOx and carbon at the nanoscale, as well as the porous structure. The SiOx/C(50) electrode, with the most appropriate carbon content, delivered a high lithium storage capacity and excellent cyclability. Specifically, a reversible capacity of 808 mA h g^-1 can be achieved at 100 mA g^-1 , retaining 666 mA h g^-1 after 100 cycles. And the reversible capacity still retained ∼550 mAh g^-1 after 1200 cycles at a current density of 0.5 A g^-1 .

Cyclohexanedodecol-Assisted Interfacial Engineering for Robust and High-Performance Zinc Metal Anode

Aqueous zinc-ion batteries (AZIBs) can be one of the most promising electrochemical energy storage devices for being non-flammable, low-cost, and sustainable. However, the challenges of AZIBs, including dendrite growth, hydrogen evolution, corrosion, and passivation of zinc anode during charging and discharging processes, must be overcome to achieve high cycling performance and stability in practical applications. In this work, we utilize a dual-functional organic additive cyclohexanedodecol (CHD) to firstly establish [Zn(H₂O)₅(CHD)]²⁺ complex ion in an aqueous Zn electrolyte and secondly build a robust protection layer on the Zn surface to overcome these dilemmas. Systematic experiments and theoretical calculations are carried out to interpret the working mechanism of CHD. At a very low concentration of 0.1 mg mL^-1 CHD, long-term reversible Zn plating/stripping could be achieved up to 2200 h at 2 mA cm^-2, 1000 h at 5 mA cm^-2, and 650 h at 10 mA cm^-2 at the fixed capacity of 1 mAh cm^-2. When matched with V₂O₅ cathode, the resultant AZIBs full cell with the CHD-modified electrolyte presents a high capacity of 175 mAh g^-1 with the capacity retention of 92% after 2000 cycles under 2 A g^-1. Such a performance could enable the commercialization of AZIBs for applications in grid energy storage and industrial energy storage.

Iron vacancies engineering of FexC@NC hybrids toward enhanced lithium-ion storage properties

Defect engineering have profound influence on the energy storage properties of electrode hybrids by adjusting their intrinsic electronic characteristics. For iron carbide based materials, however, the effect of defect (especially cation vacancies) toward their electrochemical performance are still unclear. Herein, the feasible and scalable synthesis of Fe_xC@NC with 3D honeycomb-like carbon architecture and abundant Fe vacancies via template etching is reported. Such structure enable outstanding lithium-ion storage properties owing to hierarchical pores, improved intrinsic electrochemical activity, as well as the introduction of more active sites. As a result, the Fe_xC@NC-2 presents a high reversible specific capacity of 1079 mAh g^-1after 1000 cycles. Moreover, an excellent cycling stability can be achieved via maintaining a high-capacity retention (689 mAh g^-1, 98.4%) over 1000 cycles at 5 A g^-1. This study provides a feasible strategy for developing high-performance hybrids with hierarchical pore and rich defects structures.

Surface modification with lithium silicate to enhance the electrochemical performance of high-valence metal oxide compound MnTeMoO6

MnTeMoO6@Li2SiO3 composite electrodes exhibit enhanced electrochemical performance with lower activation energy.

Constructing epitaxially grown heterointerface of metal nanoparticles and manganese dioxide anode for high-capacity and high-rate lithium-ion batteries

Low ion migration rate and irreversible change in the valence state in transition-metal oxides limit their application as anode materials in Li-ion batteries (LIBs). Interfacial optimization by loading metal particles on semiconductor can change the band structure and thus tune the inherent electrical nature of transition-metal oxide anode materials for energy applications. In this work, Au nanoparticles are epitaxially grown on MnO₂ nanoroads (MnO₂-Au). Interestingly, the MnO₂-Au anode shows excellent electrochemical activity. It delivers high reversible capacity (about 2-3 fold compared to MnO₂) and high rate capability (740 mA h g^-1 at 1 A g^-1). The electron holography and density functional theory (DFT) results demonstrate that the Au particles on the surface of MnO₂ can form a negative charge accumulation area, which not only improves the Li ion migration rate but also catalyzes the transition of MnO_x to Mn⁰. This study provides a direction to heterointerface fabrication for transition-metal oxide anode materials with desired properties for high-performance LIBs and future energy applications.

Co3ZnC@NC Material Derived from ZIF-8 for Lithium-Ion Capacitors

Metal-organic framework (MOF)-derived carbon materials were widely reported as the anodes of lithium-ion capacitors (LICs). However, tunning the structure and electrochemical performance of the MOF-derived carbon materials is still challenging. Herein, metal carbide materials of Co3ZnC@NC-8:2 were obtained by the pyrolysis of the MOF materials of Co0.2Zn0.8ZIF-8 (Zn/Co ratio of 8:2). A half-cell assembled with the Co3ZnC@NC-8:2 electrode exhibits a discharge capacity of the electrode material of 598 mAh g-1 at a current density of 0.1 A g-1. After 100 cycles, the retention rate of discharge specific capacity is about 90%. The high performance of Co3ZnC@NC-8:2 is ascribed to its high crystalline degree and well-defined structure, which facilitates the intercalation/deintercalation of lithium ions and buffers the volume change during the charge/discharge process. The high capacitance contribution ratio calculated by cyclic voltammetry (CV) curves at different scanning rates indicates the pseudocapacitance storage mechanism. LICs constructed from the Co3ZnC@NC-8:2 material have a rectangular CV curve, while the charge-discharge curve has a symmetrical triangular shape. This study indicates that MOF-derived carbon is one of the promising materials for high-performance LICs.