Improving rate capacity and cycling stability of Si-anode lithium ion battery by using copper nanowire as conductive additive

Abstract

Measures of using carbon nanomaterials as conductive additives or coating carbon are popularly taken to relieve the huge volume expansion of Si-anode. However, these measures usually lead to the consumption of lithium ions and excessive formation of unstable solid-electrolyte interface film, resulting in a low initial coulombic efficiency (ICE), unsatisfied capacity and cycling stability. To address this issue, copper nanowire (CuNW) with high electrical conductivity is used instead of acetylene black as an inactive conductive additive for Si-anode in this study. Compared with Si anode with acetylene black conductive additive, the Si-anode with the CuNW conductive additive exhibits a significantly improved rate capacity (1686.9 mA h g−1 at 1 C) and cycling stability (capacity retention of ∼88.2% after 100 cycles), and a higher ICE of ∼93.1%. The improved performance can be attributed to the one-dimensional characteristic and excellent electrical conductivity of the CuNW, which can construct robust and effective conducting networks in the Si-anode, maintain efficient electron transfer pathways and significantly reduces the cell resistance. Furthermore, the CuNW is inactive to Li ions insertion and extraction and can reduce the irreversible reactions with electrolyte and the consumption of lithium ions, leading to the high ICE.