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

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<middle dot>g(-1), 181.77 mAh<middle dot>g(-1), and 174.82 mAh<middle dot>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.