Graphene-Anchored Mesoporous Mn–Co Oxide Battery-like Materials for Ultrahigh Performance Hybrid Supercapacitors

The energy storage mechanism of hybrid supercapacitors originates mainly from Faradaic charge transfer generated on/near the surface of Faradaic pseudocapacitive materials. Therefore, the development of electrode materials with superior electron collection efficiency and energy storage capacity is urgently needed for supercapacitor applications. Herein, we design and synthesize battery-like Mn–Co oxide/rGO hybrid nanostructures via a facile two-step process. By introducing graphene, the structural properties of Mn–Co oxide (MnCoO) are effectively modified. In addition, benefiting from the Schottky barrier caused by the difference in work functions, free electrons are trapped and accumulated at the Fermi level, enabling Mn–Co oxide to obtain superior electron accumulation effect. The fabricated hybrid electrode exhibits enhanced energy storage performances, with ultrahigh specific capacitance of 2749 F g–1 (381.8 mAh g–1) and remarkable cycling durability of 95.7% retention over 8000 cycles at 10 A g–1. When fabricated as an asymmetric supercapacitor (ASC), an excellent energy density of 35.5 Wh kg–1 at 1008.2 W kg–1 can be delivered for the MnCoO-rGO/NF//rGO/NF device. This study can offer guidance for constructing high-performance supercapacitors through interfacial electronic structure design.