Two-dimensional porous silicon nanosheets as anode materials for high performance lithium-ion batteries
JJ Tang and QF Yin and Q Wang and QQ Li and HT Wang and ZL Xu and HM Yao and J Yang and XY Zhou and JK Kim and LM Zhou, NANOSCALE, 11, 10984-10991 (2019).
In this paper, silicon nanosheets (Si-NSs) are chemically synthesized by using graphene oxide nanosheets as the template. The obtained Si-NSs, which are aggregations of silicon nanocrystals with a size of similar to 10 nm, are applied directly as the anode material for lithium ion batteries, delivering a reversible capacity of 800 mA h g(-1) after 900 cycles at a rate as high as 8400 mA g(-1). Ex situ measurements and in situ observations show the positive effect of the mesoporous structure on the structural stability of Si-NSs. The evolution and survivability of the porous structures during lithiation and delithiation processes are investigated by molecular dynamics simulations, demonstrating that the porous structure can enhance the amount of " active" Li atoms during the stable stage of cycling and therefore promote mass capacity. The longer the survival of the porous structure, the longer the high mass capacity can be retained.
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