Cu&amp;Si Core–Shell Nanowire Thin Film as High-Performance Anode Materials for Lithium Ion Batteries

Lifeng Zhang,Junfeng Yang,Linchao Zhang,Zhuoming Xie

doi:10.3390/app11104521

Cu&Si Core–Shell Nanowire Thin Film as High-Performance Anode Materials for Lithium Ion Batteries

Lifeng Zhang, Junfeng Yang + Show 2 more

Open Access

https://doi.org/10.3390/app11104521

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Abstract

Cu@Si core–shell nanowire thin films with a Cu3Si interface between the Cu and Si were synthesized by slurry casting and subsequent magnetron sputtering and investigated as anode materials for lithium ion batteries. In this constructed core–shell architecture, the Cu nanowires were connected to each other or to the Cu foil, forming a three-dimensional electron-conductive network and as mechanical support for the Si during cycling. Meanwhile, the Cu3Si layer can enhance the interface adhesion strength of the Cu core and Si shell; a large amount of void spaces between the Cu@Si nanowires could accommodate the lithiation-induced volume expansion and facilitate electrolyte impregnation. As a consequence, this electrode exhibits impressive electrochemical properties: the initial discharge capacity and initial coulombic efficiency is 3193 mAh/g and 87%, respectively. After 500 cycles, the discharge capacity is about 948 mAh/g, three times that of graphite, corresponding to an average capacity fading rate of 0.2% per cycle.

Highlights

Si suffers from as high as 300% volume change upon fulllithiation, inducing pulverization of the silicon particles and losing electrical connectivity from the current collector and the thickening of the solid electrolyte interface (SEI) layer upon cycling; these eventually hinder the practical application of Si-based anode materials in lithium ion batteries (LIBs) [3,4]
Cui et al successfully synthesized a core–shell structured Si nanowire with a crystallite Si (c-Si) core and amorphous Si (a-Si) shell, in which the a-Si shell can be cycled alone as lithium ion storage whereas the c-Si core remains intact as mechanical sturdy support and efficient electron transport pathways by setting an appropriate cut-off potential owing to the higher lithiation potential of a-Si than c-Si (∼220 mV vs. ∼120 mV, respectively), resulting in significant improvement in electrochemical performance over traditional Si nanowires, such as a high charge capacity of 1000 mAh/g and a capacity retention of 90% over 100 cycles [9]
Cu@Si Core–Shell Nanowire Thin Film (CSNWF) were fabricated through slurry casting and subsequent magnetron sputtering and investigated as anode materials for lithium ion batteries

Summary

Introduction

Si suffers from as high as 300% volume change upon full (de)lithiation, inducing pulverization of the silicon particles and losing electrical connectivity from the current collector and the thickening of the solid electrolyte interface (SEI) layer upon cycling; these eventually hinder the practical application of Si-based anode materials in LIBs [3,4] To tackle these issues, enormous attention has been directed towards the development of Si nanostructured materials [5], of which Si nanowires (SiNWs) have attracted considerable interest owing to its small lithium diffusion length and facile strain relaxation during (de)lithiation [6,7].

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