Investigation on Spinel LiNi0.5Mn1.5O4 Synthesized by MnCO3 Prepared under Different Conditions for Lithium‐Ion Batteries

Abstract

AbstractLiNi0.5Mn1.5O4(LNMO) is synthesized using MnCO3 as manganese source in this paper. MnCO3 is prepared by precipitation reaction between MnSO4 and NH4HCO3. Two different adding processes of precipitant, slow dropping and rapid addition, are compared. MnCO3 particles have core‐shell structure. When the precipitant is added slowly, the shell occupies a larger proportion in MnCO3 particles. Compared to slow dropping process, rapid addition of precipitant may reduce particle size and improve dispersity of MnCO3 and LNMO particles. LNMO prepared by large MnCO3 particles (>8 μm) and small MnCO3 particles (∼1 μm) have core‐shell structure and hollow structure, respectively. LNMO with hollow structure are not stable and break easily during cycling. Slow addition process for precipitant can improve the rate performance of LNMO. When the concentration of MnSO4 solution is 0.04 mol L−1 and precipitant is added slowly, LNMO exhibits the best electrochemical performances. Its particle size is 8 μm and its discharge capacities at 0.2C and 20 C are 123 and 62 mAh g−1, respectively. After 500 cycles at 1 C, its discharge capacity is still as high as 114.1mAh g−1, which maintains 92.4 % of its initial capacity.