Enhancement of electrochemical performance in lithium-ion battery via tantalum oxide coated nickel-rich cathode materials

Nickel-rich cathode materials are increasingly being applied in commercial lithium-ion batteries to realize higher specific capacity as well as improved energy density. However, low structural stability and rapid capacity decay at high voltage and temperature hinder their rapid large-scale application. Herein, a wet chemical method followed by a post-annealing process is utilized to realize the surface coating of tantalum oxide on LiNi 0.88 Mn 0.03 Co 0.09 O 2 , and the electrochemical performance is improved. The modified LiNi 0.88 Mn 0.03 Co 0.09 O 2 displays an initial discharge capacity of ∼ 233 mAh/g at 0.1 C and 174 mAh/g at 1 C after 150 cycles in the voltage range of 3.0 V–4.4 V at 45 °C, and it also exhibits an enhanced rate capability with 118 mAh/g at 5 C. The excellent performance is due to the introduction of tantalum oxide as a stable and functional layer to protect the surface of LiNi 0.88 Mn 0.03 Co 0.09 O 2 , and the surface side reactions and cation mixing are suppressed at the same time without hampering the charge transfer kinetics.