Abstract:Nb doped Li1.16Mn0.56Ni0.28O2 samples were prepared by high-temperature solid-state method. It is found that Nb doping can increase primary particles size and reduce specific surface area. The linear change of a and c values follows Vegard''s law when the doping amounts is less than 0.1%(mass fraction), indicating that Nb enters into the transition metal site; while Nb partly exists on grain boundary or surface in the form of Nb compound, when Nb-doping amount is more than 0.1%. The sample with 0.1% Nb doping shows the best electrochemical performance with specific discharge capacity of 256.9 mAh/g (0.1 C discharge capacity) and coulombic efficiency of 87.8%, it’s capacity retention is 85.4% after 80 cycles at 0.5 C. Nb doping expands the Li slab, which is helpful to the Li+ de-intercalation. Meanwhile the strong Nb—O bond alleviates the loss of lattice oxygen and stabilizes the structure of Co-free lithium rich manganese layered oxide.256.9 mAh/g (0.1 C discharge capacity) and 87.8 % (coulombic efficiency), it’s capacity retention is 85.4 % after 80 cycles at 0.5 C. Nb doping expands the Li slab, which is helpful to the Li+ de-intercalation. Meanwhile the strong Nb-O bond alleviates the loss of lattice oxygen and stabilizes the structure of Co-free lithium rich manganese layered oxide.