Multilayer Sn-Si anodes with boundary-guided damage under Sn-selective cycling

초록

A binder-free multilayer SnSi electrode was fabricated by hot pressing and warm rolling, and then cycled between 0.3 and 1.5 V - a window chosen to retain a predominantly Sn-based response while limiting crystallineSi lithiation. Redistribution of the nominal 80Sn-20Si composition from an exposed coating to internal interfaces produced elongated powder-rich regions within a continuous Sn-rich framework. The multilayer delivered 1.05 mAh cm- 2 initially and retained 73% after 100 cycles despite a lower total areal mass than the surface-coated electrode. After 20 cycles, pure Sn showed severe surface pulverization, the coating developed dense random cracking, and the multilayer showed cracking confined to the SnSi regions, with adjacent Sn-rich layers remaining comparatively continuous. These observations are consistent with architecture-guided damage tolerance through local crack blunting or arrest and preservation of redundant Sn-rich pathways.

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