电化学阻抗谱法研究温度对三维多孔Cu6Sn5合金电极嵌锂过程的影响

摘要

Porous Cu was fabricated by electrodepositing using hydrogen bubbles as the dynamic template,and subsequently treated by annealing to increase the structural stability. The 3-dimensional porous Cu6Sn5 alloy electrode was prepared by electrodepositing using the porous Cu as the substrate. The lithiation/delithiation potentials of 3-dimensional porous Cu6Sn5 were investigated by cyclic voltammetry. The initial lithiation process of 3-dimensional porous Cu6Sn5 alloy electrode at different temperature was studied by electrochemical impedance spectroscopy. The results indicate that the Nyquist plots are composed of three regions in the main lithiation range: high frequency arc represents solid electrolyte interphase(SEI) impedance, middle frequency arc represents charge transfer impedance, and low frequency arc represents phase transformation impedance.The variation of the electrochemical impedance versus temperature was analyzed by simulating the experimental data using appropriate equivalent circuit.%采用氢气泡为动力学模板电沉积获得多孔铜,通过热处理增强其结构稳定性,并以该多孔铜为基底电沉积获得三维多孔Cu6Sn5合金电极.采用循环伏安法研究了三维多孔Cu6Sn5合金电极的嵌/脱锂电位.采用电化学阻抗谱研究了三维多孔Cu6Sn5合金电极在不同温度下的首次嵌锂过程.结果显示,在主要的嵌锂区间内,三维多孔Cu6Sn5合金电极的Nyquist图由锂离子穿过电极表面SEI膜阻抗的高频圆弧、电荷传递阻抗的中频圆弧和相变阻抗的低频圆弧3部分组成.因此,选择合适的等效电路对阻抗谱进行了模拟,并分析了其随温度的变化规律.