Reinforced Transport Kinetics and Structural Stability of Micron-Si Anode In PVDF-Based Composite Solid-State Batteries via Single-Walled Long Carbon Nanotubes

Abstract

Silicon-based anode solid‑state batteries are among the most promising systems for simultaneously achieving high energy density and enhanced safety. However, silicon anodes suffer from severe loss of electronic contact in low–electrolyte or electrolyte‑free environments due to their substantial volume changes, which significantly hinders their integration into solid‑state systems. In this work, we introduce single-walled long carbon nanotubes (SWCNTL) into micron-sized silicon (MSi) anodes to reinforce the three‑dimensional conductive network and thus optimize electrochemical performance in a solid‑state system based on poly(vinylidene fluoride)@lithium lanthanum zirconium tantalum oxide (PVDF@LLZTO)composite solid electrolyte. We demonstrate that SWCNTL promote deeper lithiation of MSi particles at elevated current densities, while simultaneously enhancing electron‑ion transport kinetics and mechanical integrity during cycling under solid-state conditions. Thus, MSi electrodes incorporating SWCNTL deliver markedly improved electrochemical performance and cycling stability in both PVDF@LLZTO-based solid-state half-cells and solid-state full cells countered with LiFePO₄(LFP)cathode. Our findings provide a viable strategy to enhance the practical application of silicon anodes in next-generation solid-state battery systems.