LAUSR

Surface coating and lattice doping are widely used to enhance the interfacial and structural stabilities of Li1.2Ni0.13Co0.13Mn0.54O2 (LNCM). In this paper, KF is used to modify LNCM for the first time. A Li+/K+ exchange in the Li-slabs is realized via a high-temperature treatment. Consequently, subsurface K+ gradient doping and surface K1-xLixF gradient coating are obtained simultaneously on LNCM. Such Li+/K+ exchange mechanism and double gradient modification are clarified by XRD, EDS line scans and HR-TEM analyses. As a result, the optimal 0.5 wt% KF modified LNCM material shows markedly alleviated voltage degradation (0.0031 V @1 cycle), improved cycling stability (88%@100 [email protected] C) and rate capability (108 mA h g-1@10 C), revealing large application potential in high energy materials.