Template-Free Electrochemical Preparation of Hexagonal CuSn Prism-Structural Electrode for Lithium-Ion Batteries

Xiaona Pan,Jinqiu Zhang,Peixia Yang,Haiyan Zhang,Xiaoyu Wen,Maozhong An

doi:10.1155/2018/1507985

Abstract

A hexagonal prism CuSn alloy was prepared at room temperature from 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCA]) by the direct template-free electrodeposition method with different concentrations of Cu(I) and Sn(II) at a low current density of 0.04 A dm−2. Moreover, the electrodeposition time was also investigated, and the results indicated that the composition of the CuSn alloy became complex and the structure turned unstable with expanding time. The cycling performance of the hexagonal prism-structural CuSn electrode was investigated, with the first discharge capacity of 345 mAh g−1 and a discharge capacity of about 210 mAh g−1 after 10 cycles.

Highlights

Tin is well investigated as an anode material for lithium-ion batteries (LIB) owing to its high storage capacity [1, 2]
Dendrite-like structures are obtained in the electrolyte with 0.04 M Cu(I) and 0.02 M Sn(II) (Figure 2(a)); with the increase in concentration, the Cu substrate is covered by a large quantity of outward growing Cu-Sn hexagonal prisms with diameters ranging from around 5 μm to 10 μm (Figure 2(b))
The different sizes of the prisms may result from the initial nucleation time which is related to the concentration of Cu(I) and Sn(II)

Summary

Introduction

Tin is well investigated as an anode material for lithium-ion batteries (LIB) owing to its high storage capacity (theoretical capacity is 993.3 mAh g−1) [1, 2]. During the charge and discharge process, Li intercalation and deintercalation causes the Sn electrode to undergo massive volume expansion and contraction due to the generation of LixSn alloy, which causes mechanical disintegration that leads to a poor cycle performance [3]. The results of investigations indicate that the Sn alloy [4,5,6] can effectively buffer the volume expansion during the charge/discharge process, improving structural stability and anode material cycle performance. A prism structure of Cu-Sn was obtained, and it could provide a high surface area and a large number of active sites for charge transfer. This structure can alleviate the large volume change that induces mechanical disintegration during the charge/ discharge process. The cycle performance of LIB, which has a hexagonal Cu-Sn prism as the anode, was investigated

Experimental

Results and Discussion

Summary