Si/FeSi2 Nanoparticles Prepared by Thermal Plasma with Stress‐releasing Effect for Li‐ion Storage

Abstract Silicon (Si) anode materials have been extensively studied due to high capacity and abundant reserves. Herein, inspired by the Li + ‐inert components, we design a novel silicon/iron silicide nanoparticles (Si/FeSi 2 NPs) prepared by thermal plasma to achieve stress‐releasing effect. The Si/FeSi 2 NPs is composed of Si and FeSi 2 which exhibits superhigh Initial Coulomb Efficiency (ICE, 89%) with a capacity of 1121 mAh g −1 after 850 cycles. The mechanism of the FeSi 2 phase in the Si/FeSi 2 NPs is studied by using finite element modelling creatively, demonstrating that the FeSi 2 phase can buffer the volume expansion effectively by reducing the stress concentration on the particles surface and releasing internal stress of particles, thus maintaining structural integrity. After combining with carbon coating layer, the Si/FeSi 2 /carbon/graphite materials (Si/FeSi 2 /C/G) can achieve superior electrochemical performances. This work provides new insight into the development of the structural stable Si‐alloy anodes towards LIBs applications.