VOx-coated LiMn2O4 nanorod clusters for lithium battery cathode materials

Abstract

VOx-coated LiMn2O4 spinel nanorod clusters as a lithium battery cathode material are prepared by mixing OV(CH3H7)3 dissolved in ethanol and LiMn2O4 powder consisting of nanorod clusters and firing this mixture at 700 °C. In the coated spinel, the V atoms are distributed within ∼30 nm of the particle surface without showing any coating layer, indicating the possible formation of a solid solution (LiMn2−xVxO4). The coated nanorod clusters exhibit a comparable rate capability to an uncoated counterpart, showing a discharge capacity of 117 mAh g−1 at a rate of 7 C (= 1400 mA g−1), which corresponds to 89% of the capacity retention ratio at room temperature. Further, the coated cathode exhibits excellent structural stability in storage at 80 °C for 24h; a significantly decreased amount of Mn dissolution (60 ppm) is observed, in contrast to that of an uncoated counterpart (5000 ppm).