High Entropy and Co-Free High Nickel Based Layered LiNi<sub>0.9</sub>Mn<sub>0.1</sub>O<sub>2</sub> Cathode for Li-Ion Batteries
Seokyoung Choi, Wuliang Feng, Yongyao Xia
Abstract
High nickel and Co-free layered cathodes (LiNi 0.9 Mn 0.1 O 2, NM) for lithium-ion batteries (LIBs) have gained researchers’ interest recently because of their high energy density and being free of toxic elements, but they still suffer from inferior electrochemical performance due to the lattice instability during cycling. Herein, we successfully improved the electrochemical performance of NM using a high-entropy strategy. A high nickel Co-free multidoped high-entropy LiNi 0.9 Mn 0.05 Zr 0.01 Nb 0.01 Ti 0.01 Al 0.01 Mg 0.01 O 2 (HE-NM, where HE represents high entropy with Zr, Nb, Ti, Al, and Mg dopants) cathode with five dopants was successfully synthesized. Owing to the effect of the multidopant, parasitic reactions and the accumulation of rock-salt phase were successfully suppressed, which led to uniformized interior stress and effectively inhibited microcracks during cycling. Consequently, HE-NM showed high thermal and structural stability with an initial discharge capacity of 206.35 mAh g –1 at 0.1 C and a retention of 76% after 100 cycles at 1 C, which showed a great advantage over the pristine NM (63%). This work provided a strategy for the stabilization of the NM cathode, which provided insight for the development of high-performance LIBs.