High power nano-LiMn₂O₄ cathode materials with high-rate pulse discharge capability for lithium-ion batteries

Nano-LiMn₂O₄ cathode materials with nano-sized particles are synthesized via a citric acid assisted sol–gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn₂O₄ are investigated. Compared with the micro-sized LiMn₂O₄, the nano-LiMn₂O₄ possesses a high initial capacity (120 mAh/g) at a discharge rate of 0.2 C (29.6 mA/g). The nano-LiMn₂O₄ also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73% at a discharge rate of 40 C. In particular, the nano-LiMn₂O₄ shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn₂O₄ could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.