Tip Effect-Driven Charge Transport Enhancement in Silicon-Carbon Anodes for All-Solid-State Lithium-Ion Batteries

Despite its pronounced impact on mass transport and local energy field modulation, the tip effect remains an underexplored strategy in the design of solid-state batteries. Here, a radial vertical graphene (RVG)-encapsulated silicon anode (RVG@Si-V) that strategically leverages the tip effect to modulate interfacial charge transport and direct the formation of solid electrolyte interphases (SEI) in all-solid-state lithium-ion batteries (ASSLIBs) is reported. The sharp geometry of RVG induces localized electric field enhancement at the electrode-electrolyte interfaces, which promotes charge accumulation and facilitates field-driven electrolyte decomposition toward thin and LiF-rich SEI formation. The structure-field coupling effectively overcomes the long-standing challenge of sluggish charge transfer kinetics at electrode-electrolyte interfaces and contributes to improved rate capability and long-term cycling stability. Electrochemical characterizations reveal that RVG@Si-V delivers excellent rate performance (940.9 mAh g⁻¹, 5 A g⁻¹) and capacity retention compared to its planar graphene (PG) counterpart (PG@Si-V) without the tip effect, retaining 76.6% of its capacity after 500 cycles at 3 A g⁻¹. This work demonstrates a previously underexplored but highly effective strategy of employing the tip effect to modulate interfacial charge transport and SEI formation in solid-state battery systems, offering critical insights toward the development of high-performance Si anodes for advanced ASSLIBs.