A Rigid‑Yet‑Flexible Architecture Enables Mechanically Adaptive Si‑Based Anodes With Dual‑Continuous Conduction for Long‑Life all‑Solid‑State Batteries

ABSTRACT

Silicon (Si)‐based anodes are promising for high‐energy‐density all‐solid‐state batteries (ASSBs) but suffer from severe volume expansion, stress accumulation, and poor intrinsic conductivity. While existing modifications often target these issues separately, a strategy capable of concurrently resolving the coupled mechanical and electrochemical challenges remains needed. Here, a “rigid‐yet‐flexible” composite anode, SiSnM (M = Ni, Ti, Y), is fabricated via vacuum induction melting and rapid quenching. Its architecture incorporates in situ formed MSi ₂ nanoparticles that pin Si expansion through dispersion strengthening and a nanoscale pinning effect, together with a ductile Sn matrix that dissipates cyclic stress, resulting in maintained structural integrity. Furthermore, continuous pathways for both electrons and ions are created, significantly enhancing charge transfer kinetics. Accordingly, the SiSnTi anode delivers a reversible capacity of 1019 mAh g ⁻¹ after 1000 cycles at 1.5 A g ⁻¹ and retains 87% capacity over 100 cycles under a low stack pressure of 50 MPa, exhibiting excellent cycling stability and mechanical adaptability. This composite design provides a practical materials strategy to address key bottlenecks in Si‐based anodes toward durable, high‐energy ASSBs.