Large Scale Synthesis of Manganese Oxide/Reduced Graphene Oxide Composites as Anode Materials for Long Cycle Lithium Ion Batteries

Abstract

Manganese oxides have been frequently used as cathodes in primary batteries. Applications of manganese oxides in secondary batteries are limited by low electrical conductivity and rapid capacity fading because of electrode pulverization and aggregation. In this study, a solid-state synthetic strategy is presented that successfully combines nanosize (∼50 nm) nickel doped α-MnO2 with reduced graphene oxides as highly stable composite anodes in lithium ion batteries. The synthesis approach is easy to scale up and suitable for industrial applications. The rationally designed Ni-α-MnO2/RGO was tested in galvanostatic half coin cells for Li+ charge–discharge studies. The results show that this composite maintains a high capacity of 615 mAh g–1 even after 200 cycles at a high current rate of 1 C (830 mA g–1), and with a high Coulombic efficiency near 99%. The anodes exhibit excellent rate capability in a wide range of rate testing from 0.2 to 10 C, without showing capacity decay. This superior anode performance is ascribed to the reduced size of α-MnO2 domains that are well dispersed in an RGO matrix, which affords good ionic/electrical conductivity, low charge transfer resistance and mitigates issues of volume expansion of the anodic active materials. This study opens up an avenue for developing the manufacturing of high-performance electrodes for real applications, such as batteries in electrical vehicles.