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Crystalline Cu-silicide stabilizes the performance of a high capacity Si-based Li-ion battery anode

Ma, Wenqing, Liu, Xizheng, Wang, Xi, Wang, Zhifeng, Zhang, Ruie, Yuan, Zhihao, Ding, Yi
Journal of materials chemistry A 2016 v.4 no.48 pp. 19140-19146
alloys, anodes, chemistry, lithium batteries, nanopores, transmission electron microscopy
Metal-silicides have demonstrated bright prospects as advanced anodes for lithium-ion batteries (LIBs). However, their roles in volume change accommodations are still unclear to us. Here, we design and fabricate a nanoporous Si/Cu₀.₈₃Si₀.₁₇/Cu composite, supported with a highly crystalline Cu-silicide/Cu rigid framework, which demonstrates a high reversible capacity of 820.4 mA h g⁻¹ after 500 cycles at a current density of 3 A g⁻¹. According to the in situ TEM, there was no obvious structural damage and electrode pulverization during the initial lithiation, and a highly crystalline LiCuSi phase was observed. Furthermore, the conversion of the Cu₀.₈₃Si₀.₁₇/LiCuSi couple during repeated cycles is highly reversible, and the structural integrity could be well maintained. These results demonstrate that the highly crystalline Cu-silicide together with the nanoporous structure contributes to the ultrastable cycle performance and the Cu-silicide/Cu rigid framework supported the superior rate performance. The present work points out a facile but effective strategy for the engineering of alloy type anodes with superior cycle and rate properties for next generation LIBs.