Enhanced Cycling Stability of Multi-Cations Doped Spinel Lithium Manganese Oxide for Rechargeable Lithium Batteries

Abstract

In order to promote the industrialization application of LiMn2O4, highperformance multi-cations doped spinel (LiAl0.03Si0.05Mg0.05Mn1.87O4) has been firstly prepared via a simple, low-cost and mass production preferred solid-state method. The light-weight elements Al (III), Mg (II) and Si (IV) occupy the octahedral (16d) sites to replace the manganese ions, and the introduction of these elements does not change the intrinsic spinel structure of LiMn2O4. No other detectable impurity phase suggests the high purity of the obtained multi-cations doped spinel. Compared with the undoped spinel, the multi-cations doped spinel shows higher crystallinity and relatively more regular surface morphology. When cycled at room temperature, the multi-cations doped spinel shows an initial discharge capacity of 118.7 mAh g-1 at 0.5 C-rate, which is lower that of the undoped spinel, but the corresponding capacity retention can reach up to 97.1% with a high discharge capacity of 115.2 mAh g-1 after 50 cycles. By contrast, the undoped spinel only shows much lower capacity retention of 74.6% with a very undesirable discharge capacity of 95.1 mAh g-1. Moreover, the multi-cations doped spinel can show much better elevated-temperature cycling stability.