材料科学
阳极
石墨烯
硅
锂(药物)
催化作用
电解质
复合数
纳米技术
碳纤维
电极
化学工程
复合材料
光电子学
化学
有机化学
医学
工程类
内分泌学
物理化学
作者
Mingshan Wang,Guoliang Wang,Shuai Wang,Jun Zhang,Jing Wang,Wei Zhong,Fan Tang,Zhenliang Yang,Jianming Zheng,Xing Li
标识
DOI:10.1016/j.cej.2018.09.110
摘要
Silicon (Si) has been considered as the next generation ideal anode material for lithium-ion batteries because of its highest theoretical capacity (4200 mAh·g−1) and affluent reserves in nature. However, the severe volume expansion and unstable solid electrolyte interface (SEI) film of Si electrode during lithiation/delithiation, as well as the poor electron conductivity have seriously restricted its commercial application. In this work, in situ catalytic growth graphene on the surface of nano-Si ([email protected]) composite is successfully developed through a novel electroless deposition approach with Ni as the catalyst. The as-prepared [email protected] composite exhibits excellent cycling stability and rate capability, which retains a reversible discharge capacity up to 1909 mAh g−1 after 100 cycles at 0.2 A g−1, and is able to deliver a discharge capacity of 975 mAh g−1 even at a high current density of 52 A g−1. The results indicate that a folded multi-layers graphene could be uniformly grown on the nano-Si particles by permeating the Ni catalytic layer using the triethylene glycol (triglycol) as carbon source. The folded multi-layers graphene could maintain the framework structure of the composite during the electrochemical cycling for its excellent mechanical performance and outstanding flexibility, which could relieve volume expansion/shrinkage of Si during repeated Li+ intercalation/extraction. Moreover, the strong connection between the graphene and nano-Si in three dimensional also could provide abundant transport pathway for the electron transportation to the surface of Si particles. The most important thing is that the multi-layer graphene could protect the nano-Si particles from being directly exposed to the electrolyte, which is beneficial for maintaining the stability of SEI films.
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