Cube-like and plate-like LiLi0.2Mn0.54Ni0.13Co0.13O2 particles are obtained after treated in LiCl and KCl molten salts at 800 °C, respectively, comparing to the ball-like original particles calcined in air. The oxide treated in KCl molten salt with large specific area of 17.05 m2 g−1 delivers high discharge capacities of 254.1 mAh g−1 and 168.5 mAh g−1 at current densities of 200 mA g−1 and 2000 mA g−1, respectively. In addition, enhanced cycle stability with capacity retention of 94.9% after 80 cycles at charge–discharge current densities of 200 mA g−1 is obtained for the oxide treated in LiCl molten salt with sacrifice of a little capacity. Such electrochemical performance change is proved to be independent of Li+ diffusion coefficient. It appears that the treatment in molten salts can effectively reform the electrochemical performances of LiLi0.2Mn0.54Ni0.13Co0.13O2 cathode materials for various applications. •Cube and plate-like particles are obtained after treated in LiCl and KCl molten salts.•Oxide treated in KCl molten salt has large specific area of 17.05 m2 g−1.•And discharge capacity of 168.5 mAh g−1 is obtained at 10 C.•Oxide treated in LiCl molten salt has enhanced capacity retention of 94.9%.