Microwave synthesis of spherical spinel LiNi0.5Mn1.5O4 as cathode material for lithium-ion batteries

Highlights: ► Spherical LiNi0.5Mn1.5O4 was synthesized through microwave heat treatment. ► The microwave approach reduced the oxygen loss and the excessive grain growth. ► The method was effective for solving the problem of cycling performance. - Abstract: Spinel LiNi0.5Mn1.5O4 cathode material with excellent electrochemical performance was synthesized through microwave heat treatment using spherical (Ni0.25Mn0.75)3O4 precursor which was prepared by a co-precipitation method. Compared with the conventional heat treatment in a muffle furnace, the microwave approach not only diminished the impurity level but also reduced the sizes of primary particles. These characters led to increase in discharge capacity and rate capability of LiNi0.5Mn1.5O4. In this study, it was found that the microwave co-precipitation method was fairly effective for further solving the problem of cycling performance, when the microwave irradiation was introduced in. The LiNi0.5Mn1.5O4 cathode material synthesized by this method delivered a discharge capacity of 142 mAh g−1 at 0.1 C rate (corresponding to 97% of the theoretical capacity), and had a capacity retention of 97% after the 50th cycle at room temperature, showing an improved electrochemical performance.