Honghe Zheng

SiOx material has been put into practical application with graphite material in lithium ion battery industries. To obtain high-performance graphite-SiOₓ laminate, layered electrode configurations including Gr/SiOx and SiOx/Gr were prepared. Compared to the randomly mixed SiOx&Gr architecture, it is found that layered configurations exhibit superior long-cycle stability and high rate capability. Integrated characterizations and kinetic analyses reveal that the layered structure effectively reconfigures stress transfer pathways, reduces electrode stress concentration, and improve the surface chemistry. Therefore, the electrode integrity and electrical contact are well preserved. Moreover, a thin and uniform SEI film is developed on the layered Gr/SiOx electrode due to the suppressed cross-talk between graphite and SiOx and the decreased interfacial side reactions. The full-cells made with the Gr/SiOx layered structure exhibit superior cycling stability and fast electrochemical kinetics. The assembled Gr/SiOx‖NCM811 full cell maintains a capacity of 131.56 mAh/g after 300 cycles at a 0.2C rate with a high reversible 102.83 mAh/g at 5C rate. The Gr/SiOx‖NCM523 pouch cell maintains a capacity retention rate as high as 80% after 400 cycles, exhibiting superior cycling stability. This work establishes a scalable electrode paradigm for the high-energy-density SiOx-graphite composite anode.

As a common anode material, natural graphite (NG) delivers variable electrochemical performance, which is largely governed by the in-situ formed solid electrolyte interphase (SEI) on its surface. The spontaneous electrolyte decomposition at the NG electrode interface and the resulting severe irreversible capacity attenuation have long been one of the primary bottlenecks restricting the practical application of NG anodes. To solve the above limitations, this work develops an in-situ constructed SEI layer with a functional molecular cross-linked framework. This protective film is fabricated through the in-situ polymerization between acrylic acid (AA) and sodium-methyl-allyl-sulfonate (SMAS). This framework exerts two complementary functions: the –COOH groups form robust covalent bonds with the NG surface, ensuring strong interfacial adhesion, while the –SO3H groups actively passivates the surface and facilitates Li+ migration. The synergy between these dual functionalities produces an SEI layer that is compact, flexible, and highly stable. Notably, the initial Coulombic efficiency (ICE) of the modified graphite anode is improved by more than 4%. Full cell paired with LiNi0.5Co0.2Mn0.3O2 cathodes exhibit outstanding cycling performance. After 500 repeated charge–discharge processes, the device retains 87.5% of its initial capacity. Further post-mortem analysis reveals that modified sulfonic acid units contribute to SEI film growth. The constructed highly Li+-conductive interfacial layer is conducive to improving the structural integrity and electrochemical stability of NG anodes.

Hard carbon (HC), as the most suitable anode material for sodium‐ion batteries, still suffers from low Coulombic efficiency and unsatisfactory fast‐charge capability, mainly because of its numerous pores that result in severe electrolyte decomposition and sluggish Na ⁺ reaction kinetics. Unlike the mainstream solid‐electrolyte interphase (SEI) strategy that solely focuses on suppressing the electrolyte decomposition or accelerating the reactions on HC anode surface, this work reveals the pore‐sealing effect of an artificial SEI through adopting a multifunctional organic small‐molecule salt (methyl blue, MB) as the surface modifier of HC and systematically elucidates its effects on the reaction kinetics of HC anode from the surface to bulk. The MB modification layer effectively seals the surface pores of commercial HC (Type‐2) and suppresses electrolyte decomposition. More importantly, theoretical calculations and empirical experiments reveal that MB accelerates the surface‐to‐bulk Na ⁺ reaction kinetics of HC anode, including Na ⁺ desolvation, adsorption on HC, transport across the SEI, and subsequent charge transfer and phase transition into Na clusters. Consequently, the MB‐modified commercial HC exhibits significantly enhanced Coulombic efficiency, superior rate capability and prolonged cycling life compared with unmodified HC.

Micro‐sized silicon (Si) is a highly attractive anode for next‐generation lithium‐ion batteries (LIBs) because of its ultrahigh specific capacity and low cost, yet its practical application is severely limited by rapid capacity decay. In this study, we develop a functional molecule, (2S,2'S)‐N,N'‐carbonylbis(2‐amino‐2‐hydroxyacetamide), to construct an in situ interfacial layer on porous micro‐Si. This layer homogenizes the pore structure by covering most micropores, thereby enabling more uniform Li‐ion insertion and alleviating the drastic phase transition of Si during lithiation. It also induces and contributes to the formation of a dense, thin, uniform, and LiF‐rich solid electrolyte interphase (SEI) with excellent electronic insulation and ionic conductivity. As a result of this coupled structural and interfacial regulation, the Si anode shows a marked improvement in electrochemical performance, with the specific capacity at 10 C rises from 945 to 2041 mAh/g, and the capacity retention improves from 15.9% to 64.2% after 1000 cycles at 25°C. In full cells without prelithiation, the initial Coulombic efficiency (ICE) increases from 83.77% to 88.11%, specific capacity at 5 C increases from 17 mAh/g to 99 mAh/g, capacity retention rises from 11.5% to 71% after 100 cycles at 45°C, demonstrating the practical promise of 100% micro‐Si anodes.

Micro‐sized silicon (Si) is a highly attractive anode for next‐generation lithium‐ion batteries (LIBs) because of its ultrahigh specific capacity and low cost, yet its practical application is severely limited by rapid capacity decay. In this study, we develop a functional molecule, (2S,2'S)‐N,N'‐carbonylbis(2‐amino‐2‐hydroxyacetamide), to construct an in situ interfacial layer on porous micro‐Si. This layer homogenizes the pore structure by covering most micropores, thereby enabling more uniform Li‐ion insertion and alleviating the drastic phase transition of Si during lithiation. It also induces and contributes to the formation of a dense, thin, uniform, and LiF‐rich solid electrolyte interphase (SEI) with excellent electronic insulation and ionic conductivity. As a result of this coupled structural and interfacial regulation, the Si anode shows a marked improvement in electrochemical performance, with the specific capacity at 10 C rises from 945 to 2041 mAh/g, and the capacity retention improves from 15.9% to 64.2% after 1000 cycles at 25°C. In full cells without prelithiation, the initial Coulombic efficiency (ICE) increases from 83.77% to 88.11%, specific capacity at 5 C increases from 17 mAh/g to 99 mAh/g, capacity retention rises from 11.5% to 71% after 100 cycles at 45°C, demonstrating the practical promise of 100% micro‐Si anodes.

Improving both the energy density and cycling stability of lithium-ion batteries is essential for next-generation energy storage systems. SiO/graphite composite anodes paired with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes represent a promising configuration for high-energy batteries, but their practical application is limited by poor cycling stability. Herein, a multifunctional separator capable of interacting simultaneously with both the anode and cathode is rationally designed. Compared with the commercial polypropylene (PP) separator, the as-prepared separator exhibits superior lithium-ion conductivity, improved thermal stability, and enhanced current resistance. Furthermore, the NCM811 cathode, separator, and SiO (15 wt%)/graphite anode are integrated through a hot-pressing process to construct an all-in-one battery architecture. This integrated configuration eliminates interfacial gaps, facilitates ion transport, suppresses polarization, and reduces interfacial impedance. As a result, the electrochemical performance of the full cell is significantly improved. Compared with conventional laminated cells using PP separators, the capacity retention after 500 cycles at 2 C increases from 46.9% to 73.5%, while the specific capacity at 5 C improves from 58.9 mAh g-1 to 116 mAh g-1. This work demonstrates that the synergistic combination of functional separator design and innovative battery architecture provides an effective strategy to address the volume-change and interfacial challenges of high-energy Si-based lithium-ion batteries.

Silicon anode volume expansion causes continuous solid electrolyte interphase (SEI) fracture, hindering their practical use. Competitive anion adsorption in the adjacent Helmholtz plane critically governs electrolyte reduction, thereby influencing the growth and properties of the SEI. We propose a polyethylenimine and phytic acid (PEIPA) composite strategy, forming a self-assembled nanolayer on silicon that combines molecular-scale anion regulation with mechanical reinforcement. The PEIPA layer selectively adsorbs PF₆^- anions, creating an anion-enriched Helmholtz layer at the Si/electrolyte interface, promoting LiF-rich SEI formation. Simultaneously, its flexible polymer matrix enables a "rigid-yet-flexible" composite SEI with a high Young's modulus (2.45 GPa) and a 21-fold increase in fracture energy. This interfacial PEIPA film significantly improves electrochemical performance, especially the rate capability and cycle life. At 10 C (42 A g^-1), the modified Si anode delivers 2000 mAh g^-1, far exceeding literature values. After 800 cycles at 0.5C, it retained 1318.5 mAh g^-1 (81.2% retention). Full cells with NCM811 cathodes further validate these advantages. This anion-regulation strategy employing functional nanolayers presents a promising avenue for optimizing SEI on Si-based anodes.

Silicon (Si) anodes hold exceptional promise for high‐energy‐density lithium‐ion batteries (LIBs) due to their ultrahigh theoretical capacity (∼4200 mAh g⁻¹). However, their commercialization is severely hindered by the significant volume expansion (∼300%) and unstable solid electrolyte interphase (SEI). Conventional SEI, predominantly composed of organic species, suffers from low ionic conductivity, low electronic insulation, and poor mechanical robustness, leading to rapid capacity decay. Herein, we propose an interface engineering strategy by decorating Si nanoparticles with an in situ conversed MgF ₂ layer (with coating integrity of 94.2%). During initial lithiation, the applied MgF ₂ layer is in situ conversed into SEI film with high ionic conductivity, electronic insulation, and better mechanical adaptability. The prepared Si@MgF ₂ ‐1 anode achieves a high initial coulombic efficiency (91.7%), superior rate capability (2000 mAh g⁻¹ at 10 C), and remarkable cycling stability (1794.9 mAh g ⁻¹ after 500 cycles). Full‐cell based on the Si@MgF ₂ ‐1 anode and NCM811 cathode further validate the practicality of this approach. The robust conversion strategy for the construction of a mechanically adaptive LiF‐rich SEI layer holds significant promise for the advancement of durable silicon‐based LIBs.

Silicon (Si) anodes hold exceptional promise for high‐energy‐density lithium‐ion batteries (LIBs) due to their ultrahigh theoretical capacity (∼4200 mAh g⁻¹). However, their commercialization is severely hindered by the significant volume expansion (∼300%) and unstable solid electrolyte interphase (SEI). Conventional SEI, predominantly composed of organic species, suffers from low ionic conductivity, low electronic insulation, and poor mechanical robustness, leading to rapid capacity decay. Herein, we propose an interface engineering strategy by decorating Si nanoparticles with an in situ conversed MgF ₂ layer (with coating integrity of 94.2%). During initial lithiation, the applied MgF ₂ layer is in situ conversed into SEI film with high ionic conductivity, electronic insulation, and better mechanical adaptability. The prepared Si@MgF ₂ ‐1 anode achieves a high initial coulombic efficiency (91.7%), superior rate capability (2000 mAh g⁻¹ at 10 C), and remarkable cycling stability (1794.9 mAh g ⁻¹ after 500 cycles). Full‐cell based on the Si@MgF ₂ ‐1 anode and NCM811 cathode further validate the practicality of this approach. The robust conversion strategy for the construction of a mechanically adaptive LiF‐rich SEI layer holds significant promise for the advancement of durable silicon‐based LIBs.