Greatly Enhanced Faradic Capacities of 3D Porous MnO/G Composites as Lithium-Ion Anodes and Supercapacitors by C-O-Mn Bonding.

Through C-O-Mn bonding, graphene nanosheets are homogeneously dispersed in porous MnO to take full advantages of porous MnO and graphene nanosheets, making the as-formed three-dimensional porous MnO/reduced graphene oxide (rGO) composite exhibit good electrochemical performance. Besides, C-O-Mn bonding is demonstrated to greatly promote the Faradic reactions of the composite, resulting in the enhancement of its real capacity in supercapacitor (SC) electrodes as well as lithium-ion battery (LIB) anodes. By simply fine-tuning the content of graphene (<7 wt %), the composite with 2.8 wt % of rGO delivers a high capacitance of 315 F g at 0.5 A g with a high rate capability of 64.7% at 30 A g and an excellent cycling stability of 105% (5 A g, 5000 cycles) as an SC electrode. Also, the one with 6.9 wt % rGO can present a reversible capacity of more than 1500 mAh g at 0.05 A g as the LIB anode, the highest value reported to date, which remains 561 mAh g at 1 A g.