Unblocked Electron Channels Enable Efficient Contact Prelithiation for Lithium-Ion Batteries

Novel strategies for constructing highly efficient silicon/carbon anodes: Chemical prelithiation and electrolyte post-treatment

Chemical prelithiation is an effective method to compensate for the loss of active lithium due to the formation of solid electrolyte interface, effectively addressing the issue of low initial coulombic efficiency (ICE) in silicon/carbon (Si/C) materials. Herein, the Si/C anode is prelithiated in a 1 M lithium-phenanthrene/2-methyltetrahydrofuran (Li-Phe/2-MTHF) solution in our work, and the prelithiated Si/C anode is followed by post-treatment with commercial electrolytes containing lithium difluorobis(oxalato)phosphate (LiDFBOP). The PSi/C-L0.5, originated from the reaction between residual Li-Phe/2-MTHF and the commercial electrolyte containing 0.5 wt% LiDFBOP, possesses the artificial SEI film, which not only contains a proper amount of LiF but also is rich in Li2C2O4 and Li3P. Among them, LiF and Li2C2O4 ensures the stability of the SEI film. Simultaneously, the synergistic effect of Li3P and LiF improves its Li+ transport kinetics. Therefore, the ICE of PSi/C-L0.5 reaches 92.50 %, and almost no drop in capacity occurs after 100 cycles at 0.5 A/g. Furthermore, the capacity stays steady at about 270 mAh/g through nearly 500 cycles at 1 A/g, achieving an impressive capacity retention rate of 97.8 %, significantly outperforming un-treated Si/C. This study offers new directions for constructing SEI films with stable structures and high Li+ kinetics transport.

Solvation layer effects on lithium migration in localized High-Concentration Electrolytes: Analyzing the diverse antisolvent Contributions

Localized high-concentration electrolytes (LHCEs) offer a new methodology to improve the functionality of conventional electrolytes. Understanding the impact of antisolvents on bulk electrolytes is critical to the construction of sophisticated LHCEs. However, the mechanism of how antisolvent modulates the electrochemical reactivity of the solvation structure in LHCEs remains unclear. In this work, the key correlation between the physicochemical properties of antisolvents and their corresponding Lithium-ion battery (LIBs) systems has been elucidated by comprehensive multiscale theoretical simulations combined with experimental characterizations. Nine antisolvents (chain ethers and cyclic non-ethers) are investigated in a typical lithium bis(fluorosulfonyl)imide/1,2-dimethoxymethane (LiFSI/DME) system. It is highlighted that the relative molecular masses of antisolvents in the same class are positively correlated with the density. The viscosity of a liquid mixture consisting of DME and antisolvent in the same class is positively correlated with the magnitude of the interaction energy between them. Additionally, the self-diffusion coefficient of Li+ is also positively correlated with the sum of the interaction energies between Li+-DME and Li+-FSI-, which is also affected by the class of antisolvent. These results provide deep insights into the behavior and properties of LHCEs, which help to advance the design of high-performance LIBs.

Ultrathin and capacity-tunable lithium metal wires for lithium-based fiber batteries

Ultrathin lithium (Li) metal wires with tunable capacities have great promise for precise prelithiation of fiber anodes and high-energy-density Li-based fiber batteries. However, the application of Li metal in fiber batteries faces great challenges due to its mechanical fragility and the resulting limited micro-dimension manufacturing capability. These challenges impede the production of ultrathin Li wires with adjustable Li contents to match the capacities of Li-based fiber batteries. Herein, silver-plated aramid yarns (Ag/AYs) are employed to load Li metal for producing ultrathin Li wires. The bundled structure of Ag/AYs leads to the adjustable volume of oriented voids within the fibers, thus resulting in accurately tunable capacities (0.0048-2.4 mAh cm-1) and diameters (20-534 μm) of Li wires. Such thin Li wires are used to precisely compensate for Li loss during the formation cycle of the fiber graphite anodes, thereby improving the initial Coulombic efficiency from ∼88% to ∼100%. Additionally, when employed as anodes, these Li wires enabled the fiber batteries to exhibit exceptional cycling stability for 150 cycles under a relatively low negative/positive ratio of 2.06, while achieving a high energy density of 139.822 Wh kg-1 based on the total mass of the battery.

Reviving Zn Dendrites to Electroactive Zn2+ by Ion Sieve Interface

Zn0 dendrite formation during repeated plating/stripping processes limits the practical use of Zn-metal anodes in reliable and affordable energy storage. Traditional methods, including dendrite suppression and dendrite regulation, fail under demanding performance conditions due to Zn2+ diffusion limitations and concentration gradients. Here, using an in situ pre-zincation approach, a Li2ZnxTi3-xO8 (LZTO, 0 Collapse

Key Words

• Zn anode
• Zn2+ ion sieve
• dendrite‐free
• interface engineering

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MESH Headings Collapse

Grants

• 52162036 National Natural Science Foundation of China
• 22378342 National Natural Science Foundation of China
• 2021D01D08 Nature Science Foundation of Xinjiang Province
• 2022A01005-4 Xinjiang Autonomous Region Major Projects
• 2021A01001-1 Xinjiang Autonomous Region Major Projects
• No. 202006750014 China Scholarship Council
• FL210100050 Australian Research Council
• DE240100159 Australian Research Council

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Affiliation(s)

Zhenjie Liu State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Murong Xi State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Guanjie Li School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Yudai Huang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Lei Mao School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Jun Xu School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Wei Wang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Zihan Qi State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Juan Ding State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, Xinjiang, 830017, China
Shilin Zhang School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia
Zaiping Guo School of Chemical Engineering, The University of Adelaide, Engineering North, North Terrace Campus, The University of Adelaide, Adelaide, South Australia, 5069, Australia

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Collaborators Collapse

Tungsten Bronze W3Nb2O14 Nanorod: The Low-Strain and Preferred Orientation Enables Long-Life for High-Rate Lithium-Ion Storage

Tungsten bronze oxides have emerged as attractive materials for energy storage owing to their fast charge-discharge property. However, the internal weakness of low capacity and short cycling performance impedes their development in wide application. In this work, the tungsten bronze W3Nb2O14 nanorods with preferred orientation (001) were prepared by hydrothermal method for the first time. It not only displays high-rate performance but also exhibits high capacity (201 mA h g-1 at 0.2 C) and long cycling property (80% capacity retention at 50 C after 3000 cycles). Notably, in situ XRD revealed the c evolution frustrates the V increase, and the maximum unit-cell volume expansion is only 2.9% during lithiation/delithiation, reflecting the long cycle performance is benefit from the low strain and preferred orientation. The ex-situ 6Li NMR spectra revealed that the lithiation and delithiation present preference based on the size of tunnels in the crystal framework.

Artificial Electron Channels Enable Contact Prelithiation of Li-Ion Battery Anodes with Ultrahigh Li-Source Utilization

Contact prelithiation is widely used to compensate for the initial capacity loss of lithium-ion batteries (LIBs). However, the low utilization of the Li source, which suffers from the deteriorated contact interfaces, results in cycling degeneration. Herein, Li-Ag alloy-based artificial electron channels (AECs) are established in Li source/graphite anode contact interfaces to promote Li-source conversion. Due to the shielding effect of the Li-Ag alloy (50 at. % Li) on Li-ion diffusion, the dry-state interfacial corrosion is restricted. The unblocked electronic conduction across the AEC-involved interface not only facilitates the Li-source conversion but also accelerates the prelithiation kinetics during the wet-state process, resulting in an ultrahigh Li-source utilization (90.7 %). Implementing AEC-assisted prelithiation in a LiNi0.5Co0.2Mn0.3O2 pouch cell yields a 35.8 % increase in energy density and stable cycling over 600 cycles. This finding affords significant insights into the construction of an efficient prelithiation technology for the development of high-energy LIBs.

Elucidating the Chemical Pre-Lithiation Mechanism of Hard Carbon Anodes for Ultra-high Stability Lithium-Ion Batteries

The hard carbon (HC) anode materials demonstrate high capacity and excellent rate performance in lithium-ion batteries. However, HC anodes suffer from excessive loss of Li+ ions during the formation of the solid electrolyte interphase (SEI) film, leading to poor cycling stability, which hinders their large-scale applications. Herein, a facile pre-lithiation strategy is proposed to achieve multi-functional precompensation of carbon nanofibers (CNFs) anodes. Both experimental and density functional theory (DFT) calculation results revealed that the strategy compensated for the loss of Li+ ions and reacted with four structures of CNFs during pre-lithiation, including tiny graphite domains, CO-containing functional groups, defects, and micropores. Furthermore, the lithium in pre-lithiated carbon nanofibers (pCNFs) existed in various forms, consisting of LiC24 and LiC18, Li─O─C, quasi-metallic lithium, and Li+ ions. Moreover, the uniformly distributed lithium on the surface of pCNFs induced the formation of denser and more robust LiF/Li2CO3-rich SEI film, which promoted Li+ ions transport. As a result, pCNFs showed more stable cycling performance (369.8 mAh g-1, almost no decay for 1500 cycles). This work provides deeper insight into chemical pre-lithiation and offers a simple and mild strategy for highly stable batteries.

The Potential Regulation of Working Anode for Long-Term Zero-Volt Storage at 37 °C in Li-Ion Batteries

The advanced lithium-ion batteries that can tolerate zero-volt storage (ZVS) are in high demand for implantable medical devices and spacecraft. However, ZVS can raise the anode potential, leading to Cu current collector dissolution and solid-electrolyte interphase (SEI) degradation, especially at 37 °C. In this contribution, by quantitatively regulating the dosage of Li6CoO4 cathode additives, controllable potential of the working anode under abusive-discharge conditions is demonstrated. The addition of Li6CoO4 keeps zero-crossing potential (ZCP) and the potential of ZVS below 2.0 V (vs Li/Li+) for LiCoO2|mesocarbon microbead cells at 37 °C. The capacity retention ratio (CRR) increases from 69.1% and 35.9% to 98.6% and 90.8% after 10 and 20 days of ZVS, respectively. The Cu dissolution and SEI degradation are effectively suppressed, while the over-lithiated cathode exhibits high reversible capacity after ZVS. The limiting conditions of long-term ZVS are further explored and a corresponding guide map is designed. When quantitatively regulating ZCP and the potential in ZVS, Cu dissolution, SEI degradation, and irreversible conversion of the cathode constitute the limiting conditions. This contribution designs the most reasonable potential range for ZVS protection at 37 °C, and realizes the best CRR record through precise potential regulation for the first time.

Presodiation Architected Robust Surface Enables Packaging Optimal Performance of Sodium-Ion Batteries

Presodiation has shown great promise in compensating sodium storage losses. In the absence of a mechanistic understanding of how presodiation affects the surface of an electrode material, packaging optimization is restricted. Focusing on interfaces, we illustrate the working principle of presodiation in virtue of short-circuiting internal circuits. The presodiated carbon nanotubes (PS-CNTs) provide a thin, denser, and more robust solid electrolyte interfacial layer, enabling a high initial Coulombic efficiency (ICE), high power density, and cycling stability with the merits of uniformly distributed NaF. As a result, our assembled sodium-ion battery (SIB) full cell with PS-CNT has an ICE of 91.6% and an energy density of 226 Wh kg-1, which was superior to the pristine CNT control electrode (ICE of 42.9% and energy density of 163 Wh kg-1). The gained insights can be practically applied to directly promote the commercial uses of carbon-based materials in sodium-ion batteries.

Ordered mesoporous nanofibers mimicking vascular bundles for lithium metal batteries

Hierarchical self-assembly with long-range order above centimeters widely exists in nature. Mimicking similar structures to promote reaction kinetics of electrochemical energy devices is of immense interest, yet remains challenging. Here, we report a bottom-up self-assembly approach to constructing ordered mesoporous nanofibers with a structure resembling vascular bundles via electrospinning. The synthesis involves self-assembling polystyrene (PS) homopolymer, amphiphilic diblock copolymer, and precursors into supramolecular micelles. Elongational dynamics of viscoelastic micelle solution together with fast solvent evaporation during electrospinning cause simultaneous close packing and uniaxial stretching of micelles, consequently producing polymer nanofibers consisting of oriented micelles. The method is versatile for the fabrication of large-scale ordered mesoporous nanofibers with adjustable pore diameter and various compositions such as carbon, SiO2, TiO2 and WO3. The aligned longitudinal mesopores connected side-by-side by tiny pores offer highly exposed active sites and expedite electron/ion transport. The assembled electrodes deliver outstanding performance for lithium metal batteries.

Harmless pre-lithiation via advantageous surface reconstruction in sacrificial cathode additives for lithium-ion batteries

Sacrificial cathode additives have emerged as a tempting strategy to compensate the initial capacity loss (ICL) in Li-ion batteries (LIBs) manufacturing. However, the utilization of sacrificial cathode additives inevitably brings residuals, side reactions, and negative impacts in which relevant researches are still in the early stage. In this study, we conduct a systematic investigation on the effects of employing a nickel-based sacrificial additive, Li2Cu0.1Ni0.9O2 (LCNO), and propose a feasible strategy to achieve advantageous surface reconstruction on LCNO. Specifically, we build a Li5AlO4 (LAO) coating layer on the LCNO through dry ball milling and annealing treatment. This process not only consumes surface residual lithium compounds on LCNO but also demonstrates minimal detrimental effects on its performance. The surface reconstructed LCNO (SR-LCNO) reveals mitigated gas generation and suppressed structure degradation under high working voltage (＞4.1 V), thereby causing negligible negative effects on the cycling capability and rate performance of commercial cathode materials. The full cells containing SR-LCNO deliver significantly improved electrochemical properties, with no observed exacerbation of side reactions. This work awakes the awareness of the prudent utilization of sacrificial cathode additives and provides an effective strategy for harmless pre-lithiation via surface reconstructed sacrificial cathode additives.

Lithiophilic Chemistry Facilitated Ultrathin Lithium for Scalable Prelithiation

Prelithiation plays a crucial role in advancing the development of high-energy-density batteries, and ultrathin lithium (UTL) has been proven to be a promising anode prelithiation reagent. However, there remains a need to explore an adjustable, efficient, and cost-effective method for manufacturing UTL. In this study, we introduce a method for producing UTL with adjustable thicknesses ranging from 1.5 to 10 μm through blade coating of molten lithium on poly(vinylidene fluoride)-modified copper current collectors. By employing the transfer-printing method, prelithiated graphite and Si-C composite electrodes are prepared, which exhibit significantly improved initial Coulombic efficiencies of 99.60% and 99.32% in half-cells, respectively. Moreover, the energy densities of Li(NiCoMn)1/3O2 and LiFePO4 full cells assembled with the prelithiated graphite electrodes increase by 13.1% and 23.6%, respectively.

Critical Review of Emerging Pre-metallization Technologies for Rechargeable Metal-Ion Batteries

Low Coulombic efficiency, low-capacity retention, and short cycle life are the primary challenges faced by various metal-ion batteries due to the loss of corresponding active metal. Practically, these issues can be significantly ameliorated by compensating for the loss of active metals using pre-metallization techniques. Herein, the state-of-the-art development in various pr-emetallization techniques is summarized. First, the origin of pre-metallization is elaborated and the Coulombic efficiency of different battery materials is compared. Second, different pre-metallization strategies, including direct physical contact, chemical strategies, electrochemical method, overmetallized approach, and the use of electrode additives are summarized. Third, the impact of pre-metallization on batteries, along with its role in improving Coulombic efficiency is discussed. Fourth, the various characterization techniques required for mechanistic studies in this field are outlined, from laboratory-level experiments to large scientific device. Finally, the current challenges and future opportunities of pre-metallization technology in improving Coulombic efficiency and cycle stability for various metal-ion batteries are discussed. In particular, the positive influence of pre-metallization reagents is emphasized in the anode-free battery systems. It is envisioned that this review will inspire the development of high-performance energy storage systems via the effective pre-metallization technologies.

Oxygen Vacancy-Tailored Schottky Heterojunction Activates Interface Dipole Amplification and Carrier Inversion for High-Performance Potassium-Ion Batteries

An oxygen vacancy-tailored Schottky heterostructure composed of polyvinylpyrrolidone-assisted Bi2 Sn2 O7 (PVPBSO) nanocrystals and moderate work function graphene (mWFG, WF = 4.36 eV) is designed, which in turn intensifies the built-in voltage and interface dipole across the space charge region (SCR), leading to the inversion of majority carriers for facilitating K+ transport/diffusion behaviors. Thorough band-alignment experiments and interface simulations reveal the dynamics between deficient BSO and mWFG, and how charge redistribution within the SCR leads to carrier inversion, demonstrating the impact of different defect engineering degrees on the amplification of Schottky junctions. The ordered transport of bipolar carriers can boost electrons and K ions easily passing through the inner and outer surfaces of the heterostructure. With high activity and low resistance in electrochemical reactions, the PVPBSO/mWFG exhibits an attractive capacity of 430 mA h g-1 and a rate capability exceeding 2000 mA g-1 , accompanied by minimal polarization and efficient utilization of conversion-alloying reactions. The substantial cell capacity and high-redox plateau of PVPBSO/mWFG//PB contribute to the practical feasibility of high-energy full batteries, offering long-cycle retention and high-voltage output. This study emphasizes the direct importance of interface and junction engineering in improving the efficiency of diverse electrochemical kinetic and diffusion processes for potassium-ion batteries.

Electrolyte-assisted low-voltage decomposition of Li2C2O4 for efficient cathode pre-lithiation in lithium-ion batteries

Lithium oxalate (Li2C2O4) is an attractive cathode pre-lithiation additive for lithium-ion batteries (LIBs), but its application is hindered by its high decomposition potential (>4.7 V). Due to the liquid-solid synergistic effect of the NaNO2 additive and the LiNi0.83Co0.07Mn0.1O2 (NCM) cathode material, the decomposition efficiency of micro-Li2C2O4 reaches 100% at a low charge cutoff voltage of 4.3 V. Our work boosts the widespread practical application of Li2C2O4 by a simple and promising electrolyte-assisted cathode pre-lithiation strategy.

Unleashing the Potential of High-Capacity Anodes through an Interfacial Prelithiation Strategy

The scalable development of an environmentally adaptive and homogeneous Li+ supplementary route remains a formidable challenge for the existing prelithiation technologies, restricting the full potential of high-capacity anodes. In this study, we present a moisture-tolerant interfacial prelithiation approach through casting a hydrophobic poly(vinylidene-co-hexafluoropropylene) membrane blended with a deep-lithiated alloy (Li22Si5@C/PVDF-HFP) onto Si based anodes. This strategy could not only extend to various high-capacity anode systems (SiOx@C, hard carbon) but also align with industrial roll-to-roll assembly processes. By carefully adjusting the thickness of the prelithiation layer, the densely packed Si@C electrode (4.5 mAh cm-2) exhibits significantly improved initial Coulombic efficiency until a close-to-unit value, as well as extreme moisture tolerance (60% relative humidity). Furthermore, it achieves more than 10-fold enhancement of ionic conductivity across the electrode. As pairing the prelithiated Si@C anode with the LiNi0.8Co0.1Mn0.1O2 cathode, the 2 Ah pouch-format prototype balances an energy density of ∼371 Wh kg-1 and an extreme power output of 2450 W kg-1 as well as 83.8% capacity retention for 1000 cycles. The combined operando phase tracking and spatial arrangement analysis of the intermediate alloy elucidate that the enhanced Li utilization derives from the gradient stress dissipation model upon a spontaneous Li+ redistribution process.

Heterostructured Li3VO4-Ga2O3-embedded porous carbon nanofibers as advanced anode materials for lithium-ion batteries

The development of lithium-ion batteries (LIBs) is still facing challenges due to the design and optimization of anode materials and their Li-ion storage mechanisms. In this study, we aimed to address this issue by constructing three-dimensional hierarchical heterojunction structures using a double needle electrospinning strategy. The heterostructure was composed of insertion-type Li3VO4 and conversion/alloying-type Ga2O3 embedded porous carbon nanofibers (Li3VO4-Ga2O3@PCNF). The designed heterostructured Ga2O3 and Li3VO4 materials were found to effectively enhance charge transfer dynamics, thereby improving capacity and rate capability. Additionally, the facilitated efficient contact between the electrode and electrolyte, enabling the diffusion of ions and electrons. When applied as an anode material in LIBs, the Li3VO4-Ga2O3@PCNF composite achieved a high capacity of 630.0 mA h g-1 at 0.5 A g-1, and full capacity recovery after 6 periods of rate testing over 480 cycles. When simulating the practical application under a high discharge current of 6.0 A g-1, the Li3VO4-Ga2O3@PCNF could still deliver a high discharge capacity of 322.0 mA h g-1 after 2000 cycles. Furthermore, the composite exhibited a remarkable capacity retention of 77.2% after 2000 cycles at 6.0 A g-1. This research provides valuable guidance for the design of high-performance Li3VO4-based anodes, particularly in addressing the issue of inferior electronic conductivity.

One-Dimensional Croconate-Based Fe-CP as a High-Performance Anode Material for Lithium-Ion Batteries

Coordination polymers (CPs) have attracted greater scientific attention as promising electrode materials for lithium-ion batteries (LIBs) due to their diverse and versatile structural chemistry. This study introduces a croconate-based one-dimensional CP, namely [Fe(C5O5)(H2O)3]n) (referred to as Fe-CP), as an efficient anode material with high-performance characteristics for rechargeable LIBs. The ligand with abundant redox sites coordinating to the transition metal ion endowed the anode material with a remarkable stability in the electrolyte, in addition to high capacity, high-rate capability, and high cycling performance during charging/discharging process. The Fe-CP has a unique chain-based supramolecular structure, setting it apart from other porous three-dimensional molecular materials. The presence of unrestricted channels between the chains facilitates the diffusion of lithium ions in this unique structure. When tested at 100 mA g-1 over a range of voltages between 0.01 and 2.4 V, the Fe-CP anode demonstrated a noteworthy specific capacity of 521 mA h g-1 over 140 cycles. Moreover, the Fe-CP anode material exhibited excellent rate performance and demonstrated favorable cyclability. Following exposure to high charging and discharging rates of 2 A g-1, the anode ultimately regained its initial capability when the current rate was back at 100 mA g-1.

Li Plating Regulation on Fast-Charging Graphite Anodes by a Triglyme-LiNO3 Synergistic Electrolyte Additive

Graphite anodes are prone to dangerous Li plating during fast charging, but the difficulty to identify the rate-limiting step has made a challenging to eliminate Li plating thoroughly. Thus, the inherent thinking on inhibiting Li plating needs to be compromised. Herein, an elastic solid electrolyte interphase (SEI) with uniform Li-ion flux is constructed on graphite anode by introducing a triglyme (G3)-LiNO3 synergistic additive (GLN) to commercial carbonate electrolyte, for realizing a dendrite-free and highly-reversible Li plating under high rates. The cross-linked oligomeric ether and Li3 N particles derived from the GLN greatly improve the stability of the SEI before and after Li plating and facilitate the uniform Li deposition. When 51 % of lithiation capacity is contributed from Li plating, the graphite anode in the electrolyte with 5 vol.% GLN achieved an average 99.6 % Li plating reversibility over 100 cycles. In addition, the 1.2-Ah LiFePO4 | graphite pouch cell with GLN-added electrolyte stably operated over 150 cycles at 3 C, firmly demonstrating the promise of GLN in commercial Li-ion batteries for fast-charging applications.

A Molecularly Engineered Cathode Lithium Compensation Agent for High Energy Density Batteries

Prelithiating cathode is considered as one of the most promising lithium compensation strategies for practical high energy density batteries. Whereas most of reported cathode lithium compensation agents are deficient owing to their poor air-stability, residual insulating solid, or formidable Li-extracting barrier. Here, this work proposes molecularly engineered 4-Fluoro-1,2-dihydroxybenzene Li salt (LiDF) with high specific capacity (382.7 mAh g^-1 ) and appropriate delithiation potential (3.6-4.2 V) as an air-stable cathode Li compensation agent. More importantly, the charged residue 4-Fluoro-1,2-benzoquinone (BQF) can synergistically work as an electrode/electrolyte interface forming additive to build uniform and robust LiF-riched cathode/anode electrolyte interfaces (CEI/SEI). Consequently, less Li loss and retrained electrolyte decomposition are achieved. With 2 wt% 4-Fluoro-1,2-dihydroxybenzene Li salt initially blended within the cathode, 1.3 Ah pouch cells with NCM (Ni92) cathode and SiO/C (550 mAh g^-1 ) anode can keep 91% capacity retention after 350 cycles at 1 C rate. Moreover, the anode free of NCM622+LiDF||Cu cell achieves 78% capacity retention after 100 cycles with the addition of 15 wt% LiDF. This work provides a feasible sight for the rational designing Li compensation agent at molecular level to realize high energy density batteries.

Nanostructured conversion-type anode materials of metal-organic framework-derived spinel XMn2O4 (X = Zn, Co, Cu, Ni) to boost lithium storage

Bimetallic spinel transition metal oxides play a major part in actualizing eco-friendly electrochemical energy storage systems (ESSs). However, structural precariousness and low electrochemical capacitance restrict their actual implementation in lithium-ion batteries (LIBs). To address these demerits, the sacrificial template approach has been considered as a prospective way to strengthen electrochemical stability and rate performance. Herein, metal-organic frameworks (MOFs) derived XMn₂O₄-BDC (H₂BDC = 1,4-dicarboxybenzene, X = Zn, Co, Cu, Ni) are prepared by a hydrothermal approach in order to discover the effects of various metal cations on the electrochemical performance. Among them, ZnMn₂O₄-BDC displays best electrochemical properties (1321.5 mAh g^-1 at the current density of 0.1 A g^-1 after 300 cycles) and high efficiency with accelerated Li⁺ diffusivity. Density functional theory (DFT) calculations confirm the ZnMn₂O₄ possesses the weakest adsorption energy on Li⁺ with a minimized value of -0.92 eV. In comparison with other XMn₂O₄ through traditional fabrication method, MOF-derived XMn₂O₄-BDC possesses a higher number of Li⁺ transport channels and better electric conductivity. This tactic provides a feasible and effective method for preparing bimetallic transition metal oxides and enhances energy storage applications.

Prolonged lifespan of initial-anode-free lithium-metal battery by pre-lithiation in Li-rich Li2Ni0.5Mn1.5O4 spinel cathode

Anode-free lithium metal batteries (AF-LMBs) can deliver the maximum energy density. However, achieving AF-LMBs with a long lifespan remains challenging because of the poor reversibility of Li⁺ plating/stripping on the anode. Here, coupled with a fluorine-containing electrolyte, we introduce a cathode pre-lithiation strategy to extend the lifespan of AF-LMBs. The AF-LMB is constructed with Li-rich Li₂Ni_0.5Mn_1.5O₄ cathodes as a Li-ion extender; the Li₂Ni_0.5Mn_1.5O₄ can deliver a large amount of Li⁺ in the initial charging process to offset the continuous Li⁺ consumption, which benefits the cycling performance without sacrificing energy density. Moreover, the cathode pre-lithiation design has been practically and precisely regulated using engineering methods (Li-metal contact and pre-lithiation Li-biphenyl immersion). Benefiting from the highly reversible Li metal on the Cu anode and Li₂Ni_0.5Mn_1.5O₄ cathode, the further fabricated anode-free pouch cells achieve 350 W h kg^-1 energy density and 97% capacity retention after 50 cycles.

Stable Zn Anodes with Triple Gradients

Aqueous zinc-ion batteries are highly desirable for sustainable energy storage, but the undesired Zn dendrites growth severely shortens the cycle life. Herein, a triple-gradient electrode that simultaneously integrates gradient conductivity, zincophilicity, and porosity is facilely constructed for a dendrite-free Zn anode. The simple mechanical rolling-induced triple-gradient design effectively optimizes the electric field distribution, Zn²⁺ ion flux, and Zn deposition paths in the Zn anode, thus synergistically achieving a bottom-up deposition behavior for Zn metals and preventing the short circuit from top dendrite growth. As a result, the electrode with triple gradients delivers a low overpotential of 35 mV and operates steadily over 400 h at 5 mA cm^-2 /2.5 mAh cm^-2 and 250 h at 10 mA cm^-2 /1 mAh cm^-2 , far surpassing the non-gradient, single-gradient and dual-gradient counterparts. The well-tunable materials and structures with the facile fabrication method of the triple-gradient strategy will bring inspiration for high-performance energy storage devices.

Eliminating interfacial O-involving degradation in Li-rich Mn-based cathodes for all-solid-state lithium batteries

In the pursuit of energy-dense all-solid-state lithium batteries (ASSBs), Li-rich Mn-based oxide (LRMO) cathodes provide an exciting path forward with unexpectedly high capacity, low cost, and excellent processibility. However, the cause for LRMO|solid electrolyte interfacial degradation remains a mystery, hindering the application of LRMO-based ASSBs. Here, we first reveal that the surface oxygen instability of LRMO is the driving force for interfacial degradation, which severely blocks the interfacial Li-ion transport and triggers fast battery failure. By replacing the charge compensation of surface oxygen with sulfite, the overoxidation and interfacial degradation can be effectively prevented, therefore achieving a high specific capacity (~248 mAh g^-1, 1.1 mAh cm^-2; ~225 mAh g^-1, 2.9 mAh cm^-2) and excellent long-term cycling stability of >300 cycles with 81.2% capacity retention at room temperature. These findings emphasize the importance of irreversible anion reactions in interfacial failure and provide fresh insights into constructing stable interfaces in LRMO-based ASSBs.

Prelithiation Bridges the Gap for Developing Next-Generation Lithium-Ion Batteries/Capacitors

The ever-growing market of portable electronics and electric vehicles has spurred extensive research for advanced lithium-ion batteries (LIBs) with high energy density. High-capacity alloy- and conversion-type anodes are explored to replace the conventional graphite anode. However, one common issue plaguing these anodes is the large initial capacity loss caused by the solid electrolyte interface formation and other irreversible parasitic reactions, which decrease the total energy density and prevent further market integration. Prelithiation becomes indispensable to compensate for the initial capacity loss, enhance the full cell cycling performance, and bridge the gap between laboratory studies and the practical requirements of advanced LIBs. This review summarizes the various emerging anode and cathode prelithiation techniques, the key barriers, and the corresponding strategies for manufacturing-compatible and scalable prelithiation. Furthermore, prelithiation as the primary Li⁺ donor enables the safe assembly of new-configured "beyond LIBs" (e.g., Li-ion/S and Li-ion/O₂ batteries) and high power-density Li-ion capacitors (LICs). The related progress is also summarized. Finally, perspectives are suggested on the future trend of prelithiation techniques to propel the commercialization of advanced LIBs/LICs.