Green Synthesis of Dual Carbon Conductive Network-Encapsulated Hollow SiO x Spheres for Superior Lithium-Ion Batteries

Simple Solution Plasma Synthesis of Ni@NiO as High-Performance Anode Material for Lithium-Ion Batteries Application

Pursuing of straightforward and cost-effective methods for synthesizing high-performance anode materials for lithium-ion batteries is a topic of significant interest. This study elucidates a one-step synthesis approach for a conversion composite using glow discharge in a nickel formate solution, yielding a composite precursor comprising metallic nickel, nickel hydroxide, and basic nickel salts. Subsequent annealing of the precursor facilitated the formation of the Ni@NiO composite, exhibiting exceptional electrochemical properties as anode material in Li-ion batteries: a capacity of approximately 1000 mAh g-1, cyclic stability exceeding 100 cycles, and favorable rate performance (200 mAh g-1 at 10 A g Collapse

Key Words

• Anode material
• Composite Ni@NiO
• Conversion metal oxide anodes
• Lithium-ion batteries
• One-step plasma solution synthesis

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MESH Headings Collapse

Grants

• 20-53-04010 RFBR
• F21RM-104 RFBR

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Affiliation(s)

Evgenii Beletskii Institute of Chemistry, St. Petersburg University, St. Petersburg, Universitetskaya Emb.7/9, 199034, Russia
Mikhail Pinchuk Institute for Electrophysics and Electrical Power of the Russian Academy of Sciences, Dvortsovaya Naberezhnaya 18, St. Petersburg, 191186, Russia
Vadim Snetov Institute for Electrophysics and Electrical Power of the Russian Academy of Sciences, Dvortsovaya Naberezhnaya 18, St. Petersburg, 191186, Russia
Aleksandr Dyachenko Institute for Electrophysics and Electrical Power of the Russian Academy of Sciences, Dvortsovaya Naberezhnaya 18, St. Petersburg, 191186, Russia
Alexey Volkov Institute of Chemistry, St. Petersburg University, St. Petersburg, Universitetskaya Emb.7/9, 199034, Russia
Egor Savelev Institute of Chemistry, St. Petersburg University, St. Petersburg, Universitetskaya Emb.7/9, 199034, Russia
Valentin Romanovski Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA

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Batch-Scale Synthesis and Interfacially Enhanced Stability of Silicon Suboxide-Based Anodes toward High-Performance Lithium-Ion Batteries

SiOx anode materials are among the most promising candidates for next-generation high-energy-density lithium-ion batteries (LIBs). However, their commercial application is hindered by poor conductivity, low initial Coulombic efficiency (ICE), and an unstable solid electrolyte interface. Developing cost-effective SiOx anodes with high electrochemical performance is crucial for advanced LIBs. To tackle these issues, this study utilized APTES as a silicon source and carbon nanotubes (CNTs) as additives to prepare a T-SiOx/C/CNTs composite material with N doping and in situ carbon coating using a "molecular assembly combined with controlled pyrolysis" strategy under mild conditions. The in situ carbon coating, formed by the pyrolysis of organic groups on the molecular precursor, effectively protects the inner SiOx active material. The introduced CNTs enhance electron migration and improve the rigidity of the carbon coating layer. The prelithiated T-SiOx@C/CNTs electrode achieves an ICE of 91.6%, with a specific capacity of 622 mAh g-1 after 400 cycles at 1 A g-1 and 475.8 mAh g-1 after 800 cycles. Full cell tests with commercial NCM811 cathodes further demonstrate the potential of T-SiOx@C/CNTs as a highly promising anode material. This work provides some insights into the rational design of advanced anode materials for LIBs, paving the way for their future development and application.

Establishing an Ion-Sieving Separator by Depositing Oxygen-Deficient SiOx Layer for Stabilized Zinc Metal Anode

Stable plating/stripping of Zn metal anode remains a great challenge owing to uncontrollable dendrite growth and side reactions. Ion-sieving separators is a unique and promising solution, that possess Zn2+ permeability and promote Zn2+ transport, can effectively alleviate the abovementioned problems. Ion-sieving on glass fiber separator by deposition of oxygen-deficient SiOx layer via active screen plasma technology is achieved. While having chemical composition similar to the glass fiber, the SiOx nanoparticles contain oxygen-rich vacancies that promoted dissociation of the adsorbed water and generation of the hydroxyl groups. The negatively-charged hydroxylated SiOx layer can repel SO4 2- and attract Zn2+, which can alleviate the side reactions. The strong interplay between hydroxyl groups and Zn2+ can boost Zn affinity and yield fast Zn2+ transport. Consequently, the SiOx-deposited GF separator enabled dendrite-free Zn deposition morphology, which displays lower overpotential of 18 mV and longer cycling life over 2000 h for Zn symmetric cell. Such a separator can also be easily scaled up to prepare the high-performance large-area (4 × 6 cm2) pouch Zn-based devices, showing remarkable flexibility and practicality.

Yolk-Shell Gradient-Structured SiOx Anodes Derived from Periodic Mesoporous Organosilicas Enable High-Performance Lithium-Ion Batteries

Gradient-structured materials hold great promise in the areas of batteries and electrocatalysis. Here, yolk-shell gradient-structured SiOx -based anode (YSG-SiOx /C@C) derived from periodic mesoporous organosilica spheres (PMOs) through a selective etching method is reported. Capitalizing on the poor hydrothermal stability of inorganic silica in organic-inorganic hybrid silica spheres, the inorganic silica component in the hybrid spheres is selectively etched to obtain yolk-shell-structured PMOs. Subsequently, the yolk-shell PMOs are coated with carbon to fabricate YSG-SiOx /C@C. YSG-SiOx /C@C is comprised of a core with uniform distribution of SiOx and carbon at the atomic scale, a middle void layer, and outer layers of SiOx and amorphous carbon. This unique gradient structure and composition from inside to outside not only enhances the electrical conductivity of the SiOx anode and reduces the side reactions, but also reserves void space for the expansion of SiOx , thereby effectively mitigating the stress caused by volumetric effect. As a result, YSG-SiOx /C@C exhibits exceptional cycling stability and rate capability. Specifically, YSG-SiOx /C@C maintains a specific capacity of 627 mAh g-1 after 400 cycles at 0.5 A g-1 , and remains stable even after 550 cycles at current density of 2 A g-1 , achieving a specific capacity of 519 mAh g-1 .

Boosting the Cell Performance of the SiO/Cu and SiO/PPy Anodes via In-Situ Reduction/Oxidation Coating Strategies

Silicon monoxide (SiO) has attracted great attention due to its high theoretical specific capacity as an alternative material for conventional graphite anode, but its poor electrical conductivity and irreversible side reactions at the SiO/electrolyte interface seriously reduce its cycling stability. Here, to overcome the drawbacks, the dicharged SiO anode coated with Cu coating layer is elaborately designed by in-situ reduction method. Compared with the pristine SiO anode of lithium-ion battery (293 mAh g-1 at 0.5 A g-1 after 200 cycles), the obtained SiO/Cu composite presents superior cycling stability (1206 mAh g-1 at 0.5 A g-1 after 200 cycles). The tight combination of Cu particles and SiO significantly improves the conductivity of the composite, effectively inhibits the side-reaction between the active material and electrolyte. In addition, polypyrrole-coated SiO composites are further prepared by in-situ oxidation method, which delivers a high reversible specific capacity of 1311 mAh g-1 at 0.5 A g-1 after 200 cycles. The in-situ coating strategies in this work provide a new pathway for the development and practical application of high-performance silicon-based anode.

Facile Synthesis of a SiOx-Graphite Composite toward Practically Accessible High-Energy-Density Lithium-Ion Battery Anodes

SiOx-based material is a promising candidate for lithium-ion batteries (LIBs) owing to its high theoretical capacity. The inherent disadvantages of poor electronic conductivity and large volume variation can be solved by constructing the outermost carbon layer and reserving internal voids. However, the practical application of SiOx/C composites remains a great challenge due to the unsatisfactory energy density. Herein, we propose a facile synthetic approach for fabricating SNG/H-SiOx@C composites, which are constructed by amorphous carbon, hollow SiOx (H-SiOx), and spherical natural graphite (SNG). H-SiOx alleviates volume expansion, while amorphous carbon promotes Li+ migration and stable solid electrolyte interphase (SEI) formation. The as-prepared SNG/H-SiOx@C demonstrates a high reversible capacity (465 mAh g-1), excellent durability (93% capacity retention at 0.5C after 500 cycles), lower average delithiation potential than SNG (0.143 V after 500 cycles), and a 14% gravimetric energy density improvement at a loading level of 4.5 mg cm-2. Even at a compacted density of 1.5 g cm-3, the SNG/H-SiOx@C anode presents a modest volume deformation of 14.3% after 100 cycles at 0.1C.

Nitrogen-Doped Carbon-Encapsulated Ordered Mesoporous SiOx as Anode for High-Performance Lithium-Ion Batteries

SiO_x (0<x<2) has been broadly investigated as a promising anode in lithium-ion batteries (LIBs) due to its high theoretical capacity, low cost, and proper working voltage. Nevertheless, its practical application is hindered by volume expansion during the lithiation process and low electrical conductivity, resulting in rapid capacity decay. Herein, we designed a core-shell structured nitrogen-doped carbon-encapsulated ordered mesoporous SiO_x composite (SiO_x @NC) using 3-aminophenol-formaldehyde (3-AF) as carbon and nitrogen precursor, tetraethyl orthosilicate (TEOS) as the silica precursor, and cationic surfactant cetyltrimethylammonium bromide (C₁₆ TAB) as the mesoporous template. The obtained composite electrode not only can effectively reduce the volume expansion, but also can effectively improve electronic conductivity and further enhance the charge and ion transfer kinetics. Benefiting from the unique structural merits, the obtained SiO_x @NC-2 delivers a high reversible capacity of 602.4 mAh g^-1 at 0.1 A g^-1 after 100 cycles and long-term cyclability (maintain 426.1 mAh g^-1 over 1000 cycles at 1 A g^-1 ).

Facile In Situ Cross-Linked Robust Three-Dimensional Binder for High-Performance SiOx Anodes in Lithium-Ion Batteries

Silicon oxide (SiO_x, 0 < x < 2) is considered one of the most promising anode materials for next-generation lithium-ion batteries due to its high theoretical capacity. However, its commercial application is limited by the non-negligible volume change during cycling. Herein, a three-dimensional (3D) structure of carboxymethyl cellulose (CMC) cross-linked with iminodiacetic (c-CMC-IDA₁₅₀) was facilely formed through in situ thermal cross-linking of CMC and iminodiacetic acid (IDA) in the fabrication process of the electrode, which could construct a robust network to restrain the volume change of the SiO_x anode and maintain the integrity of the electrode. In addition, the 3D cross-linked c-CMC-IDA₁₅₀ provides sufficient contact sites to improve the adhesive strength. Thus, SiO_x@c-CMC-IDA₁₅₀ shows a prolonged cycle life, achieving a capacity of 1020 mAh g^-1 after 100 cycles at a current density of 0.2 A g^-1. With the increase in the current density to 1.0 A g^-1, SiO_x@c-CMC-IDA₁₅₀ exhibits a reversible capacity of 899 mAh g^-1 after 200 cycles with a capacity retention of 70.2%. This work provides a potential perspective to fabricate high-performance SiO_x anodes and promote the stability of high-capacity Si-based anodes.

Green and Scalable Fabrication of Sandwich-like NG/SiOx/NG Homogenous Hybrids for Superior Lithium-Ion Batteries

SiOx is considered as a promising anode for next-generation Li-ions batteries (LIBs) due to its high theoretical capacity; however, mechanical damage originated from volumetric variation during cycles, low intrinsic conductivity, and the complicated or toxic fabrication approaches critically hampered its practical application. Herein, a green, inexpensive, and scalable strategy was employed to fabricate NG/SiOx/NG (N-doped reduced graphene oxide) homogenous hybrids via a freeze-drying combined thermal decomposition method. The stable sandwich structure provided open channels for ion diffusion and relieved the mechanical stress originated from volumetric variation. The homogenous hybrids guaranteed the uniform and agglomeration-free distribution of SiOx into conductive substrate, which efficiently improved the electric conductivity of the electrodes, favoring the fast electrochemical kinetics and further relieving the volumetric variation during lithiation/delithiation. N doping modulated the disproportionation reaction of SiOx into Si and created more defects for ion storage, resulting in a high specific capacity. Deservedly, the prepared electrode exhibited a high specific capacity of 545 mAh g-1 at 2 A g-1, a high areal capacity of 2.06 mAh cm-2 after 450 cycles at 1.5 mA cm-2 in half-cell and tolerable lithium storage performance in full-cell. The green, scalable synthesis strategy and prominent electrochemical performance made the NG/SiOx/NG electrode one of the most promising practicable anodes for LIBs.

Aerogel Constructed by Ultrasmall Mn-Doped Silica Nanoparticles for Superior Lithium-Ion Storage

The high internal stress during (de)lithiation, poor ionic/electronic conductivity, and relatively low specific capacity are the three critical issues for the applications of silica (SiO₂) anodes. Herein, a high-performance SiO₂ anode is designed from the microscale to the atomic scale, and for the first time, an aerogel constructed by the graphene and manganese atom (Mn)-doped ultrasmall SiO₂ nanoparticles (around 50 nm) is proposed to overcome the three issues. From the aspect of microscale, the ultrasmall SiO₂ nanoparticles and the porous feature of aerogel improve the structural stability during (de)lithiation and the lithium-ion diffusion kinetics. From the aspect of atomic scale, the doping of Mn introduces the impurity level, expands the coordination environment, and enhances the adsorption for Li⁺, boosting the ionic/electronic conductivity and the amount of the Li⁺ intercalation. Therefore, the anode ranks among the best SiO_x (0 < x ≤ 2) anodes. For example, the capacity is almost constant after 2000 cycles, and the specific capacities are around 1800, 1600, and 1300 mAh/g at 0.5, 1, and 3 A/g, respectively. Moreover, the reinforced reasons are revealed based on the density functional theory simulations and experiments.

Extra Li-Ion Storage and Rapid Li-Ion Transfer of a Graphene Quantum Dot Tiling Hollow Porous SiO2 Anode

Graphene is widely used to enhance the electrochemical performance of anodes. However, graphene tends to be vertical with the lithium-ion (Li⁺) diffusion direction, and a few heterointerfaces are formed between graphene and active materials by point-to-point contact. Herein, a graphene quantum dots (GDs) tiling hollow porous SiO₂ (HSiO₂@GDs) anode is predicted by density functional theory (DFT) and is achieved by experiments. Due to the ultrasmall size, the tiling of GDs would provide Li⁺ a rapid diffusion channel and abundant heterointerfaces (face-to-face contact) between the GDs and the hollow porous SiO₂ (HSiO₂). Moreover, owing to the higher electrostatic potential of SiO₂, the large-scale local electrical field from GDs to HSiO₂ is established at the heterointerfaces, which provide extra Li⁺ storage sites and further facilitate the Li⁺ transfer. To our knowledge, the HSiO₂@GDs shows the highest specific capacities at various current densities (such as ∼1100 mA h/g at 5 A/g and ∼2250 mA h/g at 0.2 A/g) among reported silicon oxides anodes and presents excellent cycling stability (∼1000 mA h/g after 2000 cycles at 3 A/g). Moreover, the design idea is available to design other widely studied graphene-containing anodes such as the Si, SnO₂, TiO₂, and MoS₂.

Carbon coated SiO nanoparticles embedded in hierarchical porous N-doped carbon nanosheets for enhanced lithium storage

Carbon coated SiO nanoparticles embedded in N-doped carbon nanosheets were synthesized via a scalable and cost-effective route, and exhibited enhanced cyclability and rate capability as an anode for lithium-ion batteries.

ZIF-Derived Cobalt-Containing N-Doped Carbon-Coated SiOx Nanoparticles for Superior Lithium Storage

N-Doped carbon-encapsulated SiO_x and Co nanoparticles are synthesized by the calcination of ZIF-67-coated SiO_x nanoparticles. This composite exhibits good electrochemical conductivity and superior accommodation to volume change from N-doped carbon and Co with SiO_x nanoparticles, exhibiting improved cycle and rate performances for lithium storage. It retains a capacity of 1044 mA h g^-1 over 150 cycles at 1.5 A g^-1, outperforming those without Co or N-doped carbon. It well confirms the contributions of Co- and N-doped carbon to the electrochemical properties of SiO_x. Even after 350 cycles at 1.0 A g^-1, this composite nonetheless delivers a capacity of 900 mA h g^-1. If it is coupled with LiFePO₄, the full cells show a stable cycling, indicating the promising application of this composite.

Microsphere-Like SiO2 /MXene Hybrid Material Enabling High Performance Anode for Lithium Ion Batteries

To address the non-negligible volume expansion and the inherent poor electronic conductivity of silica (SiO₂ ) material, microsphere-like SiO₂ /MXene hybrid material is designed and successfully synthesized through the combination of the Stöber method and spray drying. The SiO₂ nanoparticles are firmly anchored on the laminated MXene by the bonding effect, which boosts the structural stability during the long-term cycling process. The MXene matrix not only possesses high elasticity to buffer the volume variation of SiO₂ nanoparticles, but also promotes the transfer of electrons and lithium ions. Moreover, the microsphere wrapped with ductile MXene film reduces the specific surface area, relieves the side reactions, and enhances the coulombic efficiency. Therefore, superior electrochemical performance including high reversible capacity, outstanding cycle stability, high coulombic efficiency, especially in the first cycle, excellent rate capability as well as high areal capacity are acquired for SiO₂ /MXene microspheres anode.

Hollow Boron-Doped Si/SiOx Nanospheres Embedded in the Vanadium Nitride/Nanopore-Assisted Carbon Conductive Network for Superior Lithium Storage

SiO_x-based anode materials with high capacity and outstanding cycling performance have gained numerous attentions. Nevertheless, the poor electrical conductivity and non-negligible volume change hinder their further application in Li-ion batteries. Herein, we propose a new strategy to construct a hollow nanosphere with boron-doped Si/SiO_x decorated with vanadium nitride (VN) nanoparticles and embedded in a nitrogen-doped, porous, and partial graphitization carbon layer (B-Si/SiO_x@VN/PC). Benefiting from such structural and compositional features, the B-Si/SiO_x@VN/PC electrode exhibits a stable cycling capacity of 1237.1 mA h g^-1 at a current density of 0.5 A g^-1 with an appealing capacity retention of 87.0% after 300 cycles. Additionally, it delivers high-rate capabilities of 1139.4, 940.7, and 653.4 mA h g^-1 at current densities of 2, 5, and 10 A g^-1, respectively, and ranks among the best SiO_x-based anode materials. The outstanding electrochemical performance can be ascribed to the following reasons: (1) its hollow structure makes the Li⁺ transportation length decreased. (2) The existing nanopores facilitate the Li⁺ insertion/desertion and accommodate the volume variation. (3) The nitrogen-doped partial graphitization carbon enhances the electrical conductivity and promotes the formation of stable solid electrolyte interface layers during the repetitive Li⁺ intercalation/extraction process.

Atomic Pt Promoted N-Doped Carbon as Novel Negative Electrode for Li-Ion Batteries

In this work, platinum single-atom enhanced mushroom-based carbon (Pt₁/MC) materials have been facilely synthesized and served as novel electrode materials in lithium-ion batteries (LIBs). The as-synthesized Pt₁/MC active material shows a uniform dispersion of isolated Pt atoms on an MC support with high specific surface area and large total pore volume. As a negative electrode material for LIBs, the Pt₁/MC exhibits excellent electrochemical properties, which retains a capacity of 846 mA h g^-1 after 800 cycles at 2 A g^-1 and 349 mA h g^-1 (near to the theoretical capacity of graphite) after 6000 cycles at a high current density of 5 A g^-1. The remarkable high capacity and excellent cycling stability can be attributed to their porous nanostructures and atomic-Pt-enhanced lithium-ion storage. Atomic Pt can compound with Li⁺ ions to form a platinum-lithium alloy during the discharge and charge process. Density functional theory (DFT) calculations are performed to verify that the PtLi₅ alloy is the most stable intermedium on the MC substrate, which further enhances the lithiation and delithiation kinetics. This novel perspective is helpful to explore next-generation negative electrode materials with high capacities and good stabilities for LIBs.

High-Performance Lithiated SiOx Anode Obtained by a Controllable and Efficient Prelithiation Strategy

Silicon-based electrodes are promising and appealing for futuristic Li-ion batteries because of their high theoretical specific capacity. However, massive volume change of silicon upon lithiation and delithiation, accompanied by continual formation and destruction of the solid-electrolyte interface (SEI), leads to low Coulombic efficiency. Prelithiation of Si-based anode is regarded as an effective way for compensating for the loss of Li⁺ in the first discharging process. Here, a high-performance lithiated SiO_x anode was prepared by using a controllable, efficient, and novel prelithiation strategy. The lithiation of SiO_x is homogeneous and efficient in bulk due to well-improved Li⁺ diffusion in SiO_x. Moreover, the in situ formed SEI during the process of prelithiation reduces the irreversible capacity loss in the first cycle and thus improves the initial Coulombic efficiency (ICE). Half-cells and full cells based on the as-prepared lithiated SiO_x anode prominently increase the ICE from 79 to 89% and 68 to 87%, respectively. It is worth mentioning that the homogeneously lithiated SiO_x anode achieves stable 200 cycles in NCM622//SiO_x coin full cells. These exciting results provide applicable prospects of lithiated SiO_x anode in the next-generation high-energy-density Li-ion batteries.