Effect of Zr–Y Double Doping and Al2O3 Coating on Properties of Nickel-Rich Monomer LiNi0.6Co0.2Mn0.2O2 Cathode Material for Li-Ion Batteries

Abstract

Among the cathode materials for advanced lithium-ion batteries, Nickel-rich single crystalline LiNixCoyMn1–x–yO2(NCM) attracts great interest as promising materials owing to their excellent properties, such as superior energy density, high voltage platform, and low cost. However, Nickel-rich single NCM has insufficient cycle stability and cannot meet the demand for the high-rate capacity, which limits its application in EV and HEV. This work applied the strategies of Zr–Y dual doping and Al2O3 coating to improve the electrochemical performance of single crystalline NCM622 cathode. A series of single crystalline LiNi0.6Co0.2Mn0.2O2(NCM622), Zr–Y doped single crystalline NCM622, Al2O3-coated single crystalline NCM622 and Al2O3-coated Zr–Y dual-doped single crystalline NCM622 cathode materials were synthesized through the same roasting process. The Zr–Y double-doped single crystalline NCM622 material shows that Zr–Y ions are successfully doped into the lattice structure, with remarkable 0.1 C, 0.5 C, and 1 C discharge capacities 195.89 mAh·g−1, 181.77 mAh·g−1, and 174.82 mAh·g−1, respectively. The Al2O3 coated Zr–Y dual-doped single crystalline NCM622 materials show that Al2O3 particles are uniformly dispersed and attached to the surface of the coated samples, with cycling performance with retention achieving 98.84% after 50 cycles at 1 C.