MOF-derived Fe2O3 decorated with MnO2 nanosheet arrays as anode for high energy density hybrid supercapacitor

Abstract

The strategy of complementing the optimal energy storage potential range is used to construct core–shell M−Fe 2 O 3 @MnO 2 as an advanced anode material. The M−Fe 2 O 3 @MnO 2 //NiCo 2 O 4 HSC delivers a high energy density of 86.8 Wh kg −1 , and two such devices can light 25 LEDs for more than 210 min. • Strategies for complementary energy storage potential interval. • MnO 2 nanosheet arrays decorate on Fe 2 O 3 driven by MOF. • The M−Fe 2 O 3 @MnO 2 has excellent specific capacitance of 908.5F g −1 . • M−Fe 2 O 3 @MnO 2 //NiCo 2 O 4 delivers a high energy density of 86.8 Wh kg −1 . • Two HSC devices can brighten 25 LEDs for more than 210 min. The development of high-performance anode materials to match the fast-burgeoning cathodes is essential for the fabrication of high-energy–density supercapacitors. Hematite Fe 2 O 3 , with ultra-high theoretical capacitance, has been considered as a promising anode candidate, but the insufficient utilization of the energy storage potential range (mainly in −1.1 V ~ -0.5 V) creates obstacles for further expansion of its electrochemical performance. In this work, a pinecone-like core–shell composite, with vertically grown MnO 2 nanosheet arrays decorated on the M−Fe 2 O 3 prepared via sacrificing the Fe-MOF (MIL-88A) template, was synthesized to achieve the excellent energy storage effect at a wide potential range from −1.1 V to 0.3 V. As adjusting the MnO 2 coating amount to a suitable level, the M−Fe 2 O 3 @MnO 2 composite exhibits a prominent specific capacitance up to 908.5F g −1 as well as excellent cycle stability. Pseudocapacitance analysis interprets the essence of the kinetics process of composite materials in the energy storage process. The hybrid supercapacitor (HSC), assembled with pinecone-like M−Fe 2 O 3 @MnO 2 as the anode and urchin-like NiCo 2 O 4 as the cathode, delivers a high energy density of 86.8 Wh kg −1 at 804.1 W kg −1 . Unsurprisingly, 25 parallel blue LEDs powered by two HSC devices can illuminate for over an astonishing 210 min. This work fabricates a promising anode material for high-energy–density hybrid supercapacitors, and the strategy of complementary energy storage potential provides a novel approach for constructing high-performance energy storage systems.