ABSTRACT

Aqueous supercapacitor shows a narrow operating voltage range because of the limitation of the water electrolysis, resulting in low energy density. In this work, a nanoporous MnO₂ entangled hierarchical porous carbon skeleton (simplified to MHPC) has been successfully prepared. Aqueous asymmetric supercapacitor has been assembled by employing the MHPC as a positive electrode, a hierarchical porous carbon skeleton (HPC) as a negative electrode, and a neutral Na₂SO₄ aqueous solution as electrolyte. The assembled asymmetric supercapacitor can be stably charged in an aqueous medium in a wide voltage range of 0–2.5 V and delivers a maximum energy density of 20.8Wh/kg at a power density of 0.25 kW/kg and 25 kW/kg at an energy density of 11.1 Wh/kg in a 1 M Na₂SO₄ aqueous solution. This strategy provides a new idea for developing high-energy supercapacitor.

摘要

由于水电解的限制，水系超级电容器的工作电压范围很窄，导致能量密度低。在这项工作中，成功地制备了纳米多孔MnO _{2缠结的分级多孔碳骨架（简化为MHPC）。}以MHPC为正极，分级多孔碳骨架（HPC）为负极，中性Na ₂ SO ₄水溶液为电解质，组装了水系非对称超级电容器。组装后的非对称超级电容器可以在0-2.5 V的宽电压范围内稳定地在水介质中充电，在0.25 kW/kg的功率密度和25 kW/kg的能量密度下可提供20.8Wh/kg的最大能量密度。在 1 M Na 中的密度为 11.1 Wh/kg₂ SO ₄水溶液。该策略为开发高能超级电容器提供了新思路。