Effects of K in Mn<sub>2</sub>O<sub>3</sub> on the Electrochemical Performances of Spinel Li<sub>1.06</sub>Mn<sub>2</sub>O<sub>4</sub>

Abstract

Spinel LiMn2O4 material is one of the lithium-ion battery cathodes. It is cheap, nontoxic, and safe in use. This cathode material, Li1.06Mn2O4 was synthesized by using solid state reaction and two different starting materials. One was the Mn2O3 made from the industrial manganese carbonate with different contents of potassium, and the other was the high-purity Mn2O3 into which the same amount of potassium in the form of K2CO3 was added to form the K-doped spinel Li1.06Mn2O4. These two kinds of LiMn2O4 materials were characterized by XRD, SEM and electrochemical performance analysis. The results showed that the initial discharge capacity of the former cathode materials decreased gradually and the cycle performance was improved with the amount of potassium increasing. The Li1.06Mn2O4 with a content of 192.2 μg.g-1 of potassium presented the optimized electrochemical performances, with an initial discharge capacity of 128.974mAh.g-1, and a capacity retention rate of 89.90% after 50 cycles. The initial discharge capacity of doped Li1.06Mn2O4 dropped rapidly with the doping amount increasing and the capacity retention rate was not as good as that of the Mn2O3 made from the industrial manganese carbonate with different contents of potassium.