Magnesium and silicon co-doped LiNi0.5Mn1.5O4 cathode material with outstanding cycling stability for lithium-ion batteries

Abstract

The magnesium (Mg) and silicon (Si) co-doped LiNi0.5Mn1.5O4 sample has been obtained by sol-gel method. The effects of co-doping with magnesium and silicon ions on the phase structure, morphology and electrochemistry characteristics of LiNi0.5Mn1.5O4 are investigated by a series of physico-chemical characterizations. XRD results demonstrate that the magnesium and silicon ions successfully enter into the spinel structure and make the lattice parameter slightly increased. Moreover, the magnesium and silicon ions co-doped sample presents superior cycling stability. When cycled at 0.5 C, this sample still delivers 121 mAh g−1 after 100 cycles with outstanding retention of 98.86%, while the undoped LiNi0.5Mn1.5O4 sample only exhibits 104.5 mAh g−1 after 100 cycles with low retention of 79.17%. In addition, the Mg2+ and Si4+ co-doped sample shows outstanding rate capability and low charge transfer resistance.