High-performance asymmetric Mn(OH)2//Fe2O3 supercapacitor achieved by enhancing and matching respective properties of cathode and anode materials

For manufacturing high-performance asymmetric supercapacitors (ASCs), it is important to synthesize cathode and anode materials with excellent performance and respective stable electrochemical window to match with each other. In this work, by one-step electrodeposition and hydrothermal processes, ultra-thin multilayer amorphous Mn(OH)(2) nanosheets and porous Fe2O3 nanoparticles supported on activated carbon cloth (AC) as cathode and anode are synthesized, respectively. The Mn(OH)(2)@AC cathode shows maximum specific capacitance of 3103 mF cm 2 at (0-1) V due to unique amorphous network structure, while the Fe2O3@AC anode exhibits maximum specific capacitance of 1472 mF cm(-2) at (-1-0) V owing to large specific surface area of its porous structure. To obtain high performance ASC by matching the properties of Mn(OH)(2)@AC cathode and Fe2O3@AC anode, contributions of diffusion and capacitive controls, and comparisons of respective areal capacitances are investigated at different scan rates. The Mn(OH)(2)//Fe2O3 ASC device achieves 2 V voltage in 1 M LiNO3 aqueous electrolyte, high energy density of 5.125 mWh cm(-3) at a power density of 14.239 mW cm(-3), and maintaining 97.1% after 8000 cycles. For the simple synthesis and excellent electrochemical performance, these Fe2O3 anode and Mn(OH)(2) cathode can be used as promising electrodes for energy storage devices.

Automated summary

The ultra-thin multilayer amorphous Mn(OH)(2) nanosheets and porous Fe2O3 nanoparticles were synthesized for high-performance asymmetric supercapacitors through one-step electrodeposition and hydrothermal processes. The Mn(OH)(2)@AC cathode and Fe2O3@AC anode showed maximum specific capacitance due to their unique structures, achieving high energy density and cycle stability.