Boosting lithium storage performance of diatomite derived Si/SiOx micronplates via rationally regulating the composition, morphology and crystalline structure

Abstract

Nano- and micro-sized silicon and its low valence oxide show as one of the potentially promising anode materials for lithium-ion batteries (LIBs) with high energy density. Even so, the high price of nanosized silicon and poor tolerance against mechanical stress of microsized silicon limit their practical applications as silicon anode materials. Herein, using diatomite, a naturally occurring siliceous sedimentary rock, as a precursor, a series of porous Si/SiOx micronplates are synthesized through magnesiothermic reduction followed by an acid etching process. When evaluated as LIB anodes, the Si/SiOx micronplates exhibit significant improvement of cycle stability compared to commercial silicon anodes. Moreover, etched Si/SiOx micronplates achieve a highly reversible lithium storage capacity of 980 mAh g-1 at 100 mA g-1 after 100 cycles, which is over two times as high as unetched Si/SiOx anodes. The boosting lithium storage performance is attributed to the rational regulations of composition, morphology, and crystalline structures of microsized Si/SiOx, which demonstrate that the as-prepared Si/SiOx micronplates should be a series of promising anode materials for high energy density LIBs.