Strategy for synthesizing spherical LiNi0.5Mn1.5O4 cathode material for lithium ion batteries

• The complete process of preparing spherical LiNi0.5Mn1.5O4 was firstly investigated.
• Temperature, pH and power inputted are the crucial factors.
• LiNi0.5Mn1.5O4 exhibits high tap density and better electrochemical capability.
• This strategy is all purpose for preparing other spherical transition metal oxides.

Spherical LiNi0.5Mn1.5O4 material with high density and excellent electrochemical capability has been synthesized by a coprecipitation process combined with heat treatment. In this strategy, the critical process parameters of temperature, pH value, power inputted and calcining program are investigated in detail. Spinel LiNi0.5Mn1.5O4 with the space group of Fd3 m is obtained by optimizing these factors. The prepared powders are spherical, and the tap density reaches 2.18 g cm−3. In the voltage range of 3.0–4.9 V, The LiNi0.5Mn1.5O4 can deliver discharge capacity of 140 and 125 mAh g−1 at 0.1 C and 1.0 C rates, respectively. The product also demonstrates excellent cyclic performance. Electrochemical measurements show that the LiNi0.5Mn1.5O4/graphite cell can be normally cycled and delivers high discharge voltage and high energy density. This preparation technique can be a good candidate for synthesizing other spherical transition metal oxides materials.