A quasi-solid asymmetric supercapacitor based on MnO2-coated and N-doped pinecone porous carbon.

Porous carbon is considered as one of the most promising electrode materials for supercapacitors. In this work, we report a simple two-step preparation of porous carbon materials based on MnO₂-coated and N-doped pinecone, which was synthesized by carbonization and hydrothermal process. After electrochemical analysis, the prepared 3-N-PC@MnO₂ electrode exhibited optimal electrochemical performance. At a current density of 1 A/g, the specific capacitance of 3-N-PC@MnO₂ was as high as 167.8 F/g in a voltage window of 0–1 V. After being assembled into an asymmetric supercapacitor with the PVA/Na₂SO₄ quasi-solid electrolyte under the current density of 1 A/g, the energy density could reach 20.42 Wh/kg, the power density could achieve 799.9 W/kg, and its capacitance remained 84.5% after 3000 cycles, showing remarkable electrochemical performance. [ABSTRACT FROM AUTHOR]