Improvement of long-term cycling performance of high-nickel cathode materials by ZnO coating

Fangfang Wang,Xuesong Lu,Ruoyu Hong,Yuan Zhu,David Hui,Ying Zheng,Huiyong Liu

doi:10.1515/ntrev-2021-0020

Abstract

Abstract The high-nickel cathode material of LiNi0.8Co0.15Al0.05O2 (LNCA) has a prospective application for lithium-ion batteries due to the high capacity and low cost. However, the side reaction between the electrolyte and the electrode seriously affects the cycling stability of lithium-ion batteries. In this work, Ni2+ preoxidation and the optimization of calcination temperature were carried out to reduce the cation mixing of LNCA, and solid-phase Al-doping improved the uniformity of element distribution and the orderliness of the layered structure. In addition, the surface of LNCA was homogeneously modified with ZnO coating by a facile wet-chemical route. Compared to the pristine LNCA, the optimized ZnO-coated LNCA showed excellent electrochemical performance with the first discharge-specific capacity of 187.5 mA h g−1, and the capacity retention of 91.3% at 0.2C after 100 cycles. The experiment demonstrated that the improved electrochemical performance of ZnO-coated LNCA is assigned to the surface coating of ZnO which protects LNCA from being corroded by the electrolyte during cycling.

Highlights

The high-nickel cathode material of LiNi0.8Co0.15 Al0.05O2 (LNCA) has a prospective application for lithium-ion batteries due to the high capacity and low cost
We report the synthesis, structural characterization, and electrochemical of ZnO-coated LiNi0.8Co0.15Al0.05O2 cathodes
Celgard-2400 was used as the separator and 1 M LiPF6 dissolved in ethylene carbonate (EC) and diethyl carbonate (DEC) (1:1 in volume ratio) as the electrolyte solution

Summary

Introduction

Abstract: The high-nickel cathode material of LiNi0.8Co0.15 Al0.05O2 (LNCA) has a prospective application for lithium-ion batteries due to the high capacity and low cost. The obtained LNCA-NaAlO2 with uniform element distribution and orderly layered structure showed a high initial discharge capacity of 204.7 mA h g−1 at 0.1C and a good capacity retention of 74.1% after 200 cycles. Kim and Kim [22] used acetylacetone as a chelating agent to effectively control the Al reaction rate, improve the uniform distribution of Al, and more importantly, increase the average particle size and density of NCA Both the volumetric energy and specific capacity of LIBs were increased. Liang et al [25] found that the SiO2 coating onto the surface of LiNi0.8Co0.1Mn0.1O2 can stabilize the layered structure, effectively reduce the corrosion of the cathode material by the electrolyte, and improve the cycling performance.

Experimental

Materials characterization

Electrochemical measurements

Results and discussion

Conclusion