Conductive polymer polyaniline covering promotes the electrochemical properties of a nickel-rich quaternary cathode LiNi0.88Co0.06Mn0.03Al0.03O2

Abstract

A Ni-rich quaternary layered material, LiNi_0.88Co_0.06Mn_0.03Al_0.03O₂, demonstrates great potential as a cathode candidate for Lithium-ion batteries with high energy density. Nevertheless, the pristine LiNi_0.88Co_0.06Mn_0.03Al_0.03O₂ generally suffers from severe side reactions and transformation of the surface layer to a spinel structure during cycling. In the paper, a simple but efficient approach was taken to enhance the electrochemical properties of LiNi_0.88Co_0.06Mn_0.03Al_0.03O₂ by covering with the conductive polymer polyaniline (PANI), which could protect the cathode against the continuous corrosion of electrolyte. The PANI coated cathode with the optimal covering amount of 1.0 wt% delivered a specific capacity of 132.7 mA h g⁻¹ at a high rate of 5C and 122.9 mA h g⁻¹ at −30 °C with a rate of 1C, while the corresponding discharging capacities of only 100.2 mA h g⁻¹ and 85.5 mA h g⁻¹ were respectively obtained for the pristine cathode. In addition, the 1 wt% PANI coated LiNi_0.88Co_0.06Mn_0.03Al_0.03O₂ also exhibited outstanding cycling stability with 92.0% capacity retention after 200 cycles at 45 °C, much better than that (82.1%) of the pristine cathode. The simple covering technology using low cost raw materials endows the modification with potential practical application value.