Practical production of heteroatom-bridged and mixed amorphous–crystalline silicon for stable and fast-charging batteries†

Abstract

High-capacity silicon (Si) electroactive materials are actively explored to develop practical lithium-ion batteries (LIBs). Unfortunately, they suffer from structural instability at the material and electrode levels, resulting in early cycle failure. Therefore, various crystallographic/morphological controls of Si have been used to achieve electrochemical/structural stability and high reversible capacity to ultimately deploy Si anodes in practical applications. This study constructs mixed amorphous–crystalline Si (MACS) microparticles with localized heteroatom bridges in a Si crystal from borosilicate glass. This unique structure improves ion diffusivity and electrode integrity based on the structural modification of Si microparticles and the unusual electrochemical participation of heteroatom bridges. Finally, it exhibits capacity retention of 90.8% after 500 cycles and alleviates structural deformation with a thickness expansion of 93% for 300 cycles in a fast-charging system. The full cell, paired with LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622), shows sustainable capacity retention and electrochemical kinetics over 500 cycles. In addition, a low-cost, scalable synthetic system is demonstrated to assess the feasibility of Si production. This advanced Si structure offers a feasible way to realize a rational material structure and practical approach for stable and large-scale battery systems.