Effect of Presintering Atmosphere on Structure and Electrochemical Properties of LiNi 0.5 Mn 1.5 O ₄ Cathode Materials for Lithium‐Ion Batteries

Carbonate precursor prepared by coprecipitation‐hydrothermal method was first presintered under air and oxygen atmosphere, respectively, and calcinated with Li 2 CO 3 to achieve two LiNi 0.5 Mn 1.5 O 4 materials. The effects of presintering atmosphere on the structure, morphology and electrochemical performance of materials were investigated. It is found that LiNi 0.5 Mn 1.5 O 4 material prepared by presintering under oxygen atmosphere exhibits higher discharge capacities, enhanced rate capability and cycling performance, compared to that prepared by presintering under air atmosphere. This improvement is mainly attributed to the elimination of Li x Ni 1‐x O impurity phase, more stable crystal structure, lower Mn 3+ content, smaller particle size with homogeneous distribution, lower charge transfer resistance and higher Li + ion diffusion coefficient. Its discharge capacity at 10 C rate is 125.8 mAh g −1 and capacity retention rate after 200 cycles at 1 C is 92.6%, much higher than 111.3 mAh g −1 and 80.0% of that prepared by presintering under air atmosphere. The presintering under oxygen atmosphere is proven to be beneficial to the electrochemical performance of LiNi 0.5 Mn 1.5 O 4 material.