Selective doping of Li-rich layered oxide cathode materials for high-stability rechargeable Li-ion batteries

We report the discovery of Li-rich Li1+x[(Ni0.225Co0.15Mn0.625)(1-y)V-y]O-2 as a cathode material for rechargeable lithium-ion batteries in which a small amount of tetravalent vanadium (V4+) is selectively and completely incorporated into the manganese sites in the lattice structure. The unwanted oxidation of vanadium to form a V2O5-like secondary phase during high-temperature crystallization is prevented by uniformly dispersing the vanadium ions in coprecipitated [(Ni0.225Co0.15Mn0.625)(1-y)V-y](OH)(2) particles. Upon doping with V4+ ions, the initial discharge capacity (>275 mA h g(-1)), capacity retention, and voltage decay characteristics of the Li-rich layered oxides are improved significantly in comparison with those of the conventional undoped counterpart. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.