Hierarchical manganese cobalt sulfide core–shell nanostructures for high-performance asymmetric supercapacitors

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>High electrical conductivity and rational design of structures are two crucial routes to improving the electrochemical performance of electrode materials. However, highly conductive electrode materials with short ion-transport paths remain a challenge in energy storage. Here, we propose manganese cobalt sulfide (MnCo<SUB>2</SUB>S<SUB>4</SUB>) nanowire wrapping by a flocculent shell layer using a facile hydrothermal method with post-sulfurization treatment. The resultant MnCo<SUB>2</SUB>S<SUB>4</SUB> electrode employed for supercapacitor delivered a remarkable specific capacitance of 2067 F g<SUP>−1</SUP> at the current density of 1 A g<SUP>−1</SUP>, good rate capability, and excellent cycling stability. Moreover, an asymmetric supercapacitor device was successfully assembled using MnCo<SUB>2</SUB>S<SUB>4</SUB> and reduced graphene oxide (rGO) as electrodes, achieving a high energy density of 31.3 W kg<SUP>−1</SUP> at a power density of 800 W kg<SUP>−1</SUP>. With such outstanding electrochemical performance, this asymmetric supercapacitor device holds great potential in developing high-energy-storage applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A formation mechanism of MnCo<SUB>2</SUB>S<SUB>4</SUB> hybrid nanostructure is proposed. </LI> <LI> MnCo<SUB>2</SUB>S<SUB>4</SUB> delivers a superior rate capability and high specific capacitance. </LI> <LI> The assembled MnCo<SUB>2</SUB>S<SUB>4</SUB>//rGO supercapacitor exhibits a high energy and power densities. </LI> </UL> </P>