High Electrochemical Performance of LiFePO4 Cathode Material via In-Situ Microwave Exfoliated Graphene Oxide

Compared with thermally exfoliated graphene oxide (TEGO) prepared at high temperature of 800 °C and a long time of 12 h, microwave exfoliated graphene oxide (MEGO) is successfully synthesized at 800 W for 2 min benefiting from “inert and instant heating” of microwave irradiation and employed to optimize electrochemical performance of LiFePO4. The as-obtained LiFePO4/MEGO exhibits overwhelming superiorities to LiFePO4/TEGO, particularly in high-rate performance. Although LiFePO4/MEGO delivers the similar specific capacity of 158.1 mAh · g−1 as well as the LiFePO4/TEGO at the rate of 0.1 C, the LiFePO4/MEGO performs smaller polarization of 53.3 mV resulting in better specific energy of 518.1 Wh · kg−1 and energy efficiency of 89.8%. Even at the high rate of 10 C and 20 C, the LiFePO4/MEGO delivers excellent specific energy of 300.3 Wh · kg−1 and 229.7 Wh · kg−1 (with corresponding specific capacity of 104.3 mAh · g−1 and 87.3 mAh · g−1 respectively), much better than those of the LiFePO4/TEGO. After 2000 cycles, the LiFePO4/MEGO still performs excellent rate capabilities with 91.2% and 83.8% retention respectively.

In-situ microwave exfoliated graphene oxide (MEGO) was successfully to modify electrochemical performance of LiFePO4. Compared with in-situ thermally exfoliated graphene oxide (TEGO) prepared at high temperature of 800 °C and a long time of 12 h, MEGO was synthesized at 800 W for 2 min benefiting from “inert and instant heating” of microwave irradiation. The as-obtained LiFePO4/MEGO exhibited overwhelming superiorities to LiFePO4/TEGO, particularly in low polarization, high-rate performance and long cycle performance.Figure optionsDownload as PowerPoint slide