Enhancing electrochemical performance of graphene fiber–based supercapacitors through activation and MnO₂ loading

Solid-state supercapacitors (SSCs) are regarded as an important development direction in the future and have great potential compared with traditional supercapacitors which have safety risks such as liquid electrolyte leakage and chemical corrosion after mechanical deformation. Graphene has become a research hotspot for SSC electrode materials because of its unique two-dimensional structure and high electrical conductivity recently. In this study, we synthesized manganese dioxide–deposited porous graphene fibers as electrode materials for SSC. The porous graphene fiber was prepared by activated KOH at high temperature, and then MnO₂ was electrochemically deposited on the surface of the activated RGOF (aRGOF) to provide pseudocapacitance. An area specific capacity of 516.13 mF·cm⁻² can be provided after electrochemical deposition of MnO₂ on activated RGOF (MnO₂@aRGOF) compared with aRGOF which can provide an area specific capacity of 414.53 mF•cm⁻² at a current density of 0.4 mA•cm⁻². MnO₂@aRGOF-based SSC could maintain excellent performance under bending conditions. Moreover, MnO₂@aRGOF has regular resistance changes in different humidity environments that can be used as a humidity sensor for humidity monitoring, environmental monitoring, and so on.