Synergistically regulating the structural tolerance of Co-free Ni-rich cathode materials at high-rate through multi-heteroatoms substitution

Abstract

Cobalt-free, nickel-rich layered oxides are attracting extensive interest as cathodes to construct high-energy and sustainable lithium-ion batteries, but the intrinsic structure instability and weakened reaction kinetics deteriorate their application. Nowadays, doping engineering, especially multielement doping, has become an effective modification method for obtaining high-performance Ni-rich materials. Herein, the designed doping strategy with high oxidation states element (Zr4+, Mo6+) substituting transition metal element and Mg2+ replacing Li+ in LiNi0.9Mn0.1O2 (NM-ZMM) has been designed to enhance its electrochemical properties. The introduced doping elements with high oxidation states can generate the strong metal-O bond, which contributes to suppress the structural collapse induced by internal stress, and then maintain unblock ion channels for NM-ZMM. Meanwhile, the presence of Mg2+ can also be employed as the pillar ions to reinforce the structure stability, and occupy the Li-sites to inhibit lattice distortion during charging/discharging process. Thus, benefitting from the synergistic reinforcement of co-doping strategy, as-prepared NM-ZMM materials exhibit the prominent capacity retention (87.5 %, 210 cycles, 1C; 85.5 %, 2C, 150 cycles). Thereof, this creative strategy is crucial in strengthening the electrochemical performance of Ni-rich Co-free materials, which contributes to promote the development of high-performance and cost-effective Li-ion storage technology.