The in-situ electrochemical polymerization of thiophene on LiNi0.8Co0.1Mn0.1O2 cathode with high structural stability for lithium-ion batteries

LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), as a promising Ni-rich electrode material for lithium-ion batteries, is hindered by the interface instability and structure degradation caused by electrolyte erosion during operation. In this work, with the addition of thiophene into traditional electrolyte, the elastic conductive polythiophene (PTh) is in-situ electrochemically polymerized on the surface of NCM811 to stabilize the interface and hinder electrolyte corrosion. As expected, the PTh-modified NCM811 shows improved cycling stability at 2 C with capacity retention of 94% after 200 cycles and considerable rate capability with high specific capacity of 171.7 mAh/g at 5 C. This work provides an effective and feasible method to employ conductive polymer as elastic protective layer for electrode materials.