Efficient plasma-enhanced method for layered LiNi1/3Co1/3Mn1/3O2 cathodes with sulfur atom-scale modification for superior-performance Li-ion batteries

Abstract

In order to improve the electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂ as a lithium insertion positive electrode material, atom-scale modification was realized to obtain the layered oxysulfide LiNi_1/3Co_1/3Mn_1/3O_2−xS_x using a novel plasma-enhanced doping strategy. The structure and electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O_2−xS_x are investigated systematically, which confirms that the S doping can make the structure stable and benefit the electrochemical performance. The phys–chemical characterizations indicate that oxygen atoms in the initial LiNi_1/3Co_1/3Mn_1/3O₂ have been partially replaced by S atoms. It should be pointed out that the atom-scale modification does not significantly alter the intrinsic structure of the cathode. Compared to the pristine material, the LiNi_1/3Co_1/3Mn_1/3O_2−xS_x shows a superior performance with a higher capacity (200.4 mA h g⁻¹) and a significantly improved cycling stability (maintaining 94.46% of its initial discharge capacity after 100 cycles). Moreover, it has an excellent rate performance especially at elevated performance, which is probably due to the faster Li⁺ transportation after S doping into the layered structure. All the results show that the atom-scale modification with sulfur atoms on LiNi_1/3Co_1/3Mn_1/3O₂, which significantly improved the electrochemical performance, offers a novel anionic doping strategy to realize the atom-scale modification of electrode materials to improve their electrochemical performance.