科研之友
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摘要
Specific surface area (SSA) and graphitization degree are the most critical factors for carbon used for supercapacitors. However, synthesizing carbon materials with high SSA and graphitization degree in one material is still a challenge. Herein, we successfully get a carbon material with 3D graphitic belt skeleton and high SSA (> 2600 m(2) g(-1)) by using alkali metal as a catalyst to boost the graphitization of amorphous carbon at a relatively low temperature. The alkali metal with high activity can induce rearrangement of carbon atoms by firstly generating and then recoupling carbon dangling bonds to form graphene layers and followed self-stack into crystalline graphitic skeleton, which results in the high graphitization degree and elimination of non-carbon atoms in O-containing groups. Besides, the alkali derivatives can further produce rich porosity thus can maintain a high SSA. When used as an electrode material for supercapacitors, this carbon can deliver a large capacitance in a wide voltage window of 3.2 V in organic electrolyte and 1.0 V in aqueous electrolyte with excellent rate performance even up to 100 A g(-1) and superior cycling stability over 13,000 cycles at the same time. A high energy density of 44.7 Wh kg(-1) can be obtained at a high power density of 12.8 kW kg(-1). The excellent electrochemical performance can be attributed to its high surface area with rich mesopores for rapid ion transport, high conductivity from 3D intercrossed graphitic skeleton, and good chemical stability from low content of surface functional groups and carbon dangling bonds.
