Low-temperature crystallization via Zn–Si transient phases for long-life Li-ion battery anodes

Abstract

Silicon is a promising anode material for high-energy-density lithium-ion storage; however, its severe volumetric expansion during lithiation and limited cycling stability remain significant challenges for practical applications. In this study, we present an innovative approach to addressing these issues by designing a polymorphic nanostructure comprising amorphous, nanocrystalline, and nanoporous domains, synthesized via the decomposition of Zn–Si transient phases at low temperatures. The lithium-ion storage performance of the polymorphic silicon was further assessed in commercial 18650-type full cylindrical cells, which demonstrated outstanding cyclability—retaining 82 % of the initial capacity after 1280 cycles at a 1C rate—as well as excellent rate capability (maintaining 82.8 % capacity at 8C). Moreover, the initial lithiation-induced volume expansion of the polymorphic silicon anode was significantly suppressed to 23.5 %, compared to 32.9 % observed in a benchmark commercial counterpart. This work demonstrates that low-temperature crystallization mediated by Zn–Si transient phases is an effective strategy for engineering advanced silicon nanostructures, underscoring the significant potential of polymorphic silicon anodes for high-performance energy storage applications.