Incorporation of high-valence dopants in primary particles for strain-resistive Co-free high-Ni LiNi0. 9Mn0. 1O2 cathodes
​

Co-free high-Ni cathode materials, which offer advantages such as high energy density and low cost, exhibit unsatisfactory cyclic life due to severe c-lattice distortion during cycling. In existing doping strategies, charge imbalance and ionic size differences with Ni3+ prevent the incorporation of high-valence dopants into primary particles during the calcination, thereby limiting their ability to suppress lattice strain. In this study, we employ a new doping strategy utilizing organic surfactants during the co-precipitation process to homogeneously position Zr4+ ions within the primary particles of LiNi0.9Mn0.1O2. Zr4+ ions located within the primary particles exerted a pillar effect, significantly enhancing the structural robustness of the material. During the first cycle, the c-lattice contraction is reduced, effectively inhibiting microcrack formation in the particles. As a result, it exhibits a significantly improved capacity retention of 98.6 % (189.2 mAh g− 1 ) after 100 cycles.