In Situ Copper Coating on Silicon Particles Enables Long Durable Anodes in Lithium-Ion Batteries

Abstract

Addressing the significant obstacles of volume expansion and inadequate electronic conductivity in silicon-based anode materials during lithiation is crucial for achieving a long durable life in lithium-ion batteries. Herein, a high-strength copper-based metal shell is coated in situ onto silicon materials through a chemical combination of copper citrate and Si–H bonds and subsequent heat treatment. The formed Cu and Cu3Si shell effectively mitigates the mechanical stress induced by volume expansion during lithiation, strengthens the connection with the copper substrate, and facilitates electron transfer and Li+ diffusion kinetics. Consequently, the composite exhibits a reversible specific capacity of 1359 mA h g–1 at 0.5 A g–1 and maintains a specific capacity of 837 mA h g–1 and an 83.5% capacity retention after 400 cycles at 1 A g–1, surpassing similar reports on electrochemical stability. This facile copper plating technique on silicon surfaces may be used to prepare high-performance silicon-based anodes or functional composites in other fields.

Simple and Safe Synthesis of Yolk-Shell-Structured Silicon/Carbon Composites with Enhanced Electrochemical Properties

“…Figure 4 b,e reveal values of 0.686 and 0.789, respectively, implying a mixed electrochemical kinetics mechanism in the Si@Sn@C and Si@void@C electrodes. The contribution ratio of the reaction rates of the Si@Sn@C and Si@void@C electrodes can be computed using Formula (2): where and represent the diffusion-controlled and surface-controlled capacities [ 49 , 50 ], respectively. Figure 4 c,f demonstrate that the capacitive contribution ratios of Si@Sn@C and Si@void@C at a scan rate of 0.8 mV s −1 are 71% and 74%, respectively.…”

“…where k 1 v and k 2 v 0.5 represent the diffusion-controlled and surface-controlled capacities [49,50], respectively. Figure 4c,f demonstrate that the capacitive contribution ratios of Si@Sn@C and Si@void@C at a scan rate of 0.8 mV s −1 are 71% and 74%, respectively.…”