The impurities of coal plague its values not only for fuels but also for preparing functional carbon materials.coal activated carbon
Herein, we aim to develop a clean and one-step strategy to prepare activated carbon by molten salt leaching and electrolysis approach to converting anthracite/lignite to carbon for electrochemical supercapacitors. First, the major impurities such as silica and alumina were removed by a combined molten salt and water leaching process without using any toxic acid or alkaline solutions. Meanwhile, the carbonization and activation of coals take place together in the water- and oxygen-free molten salt medium. Moreover, the electrolysis can further increase the specific capacitance of the coal-derived carbon by the electrochemical regulation of carbon in molten salt using a low-cost and oxygen-evolution inert anode. The as-obtained carbon delivers a capacitance of 190 F g−1 at 5 A g−1 and shows nearly no capacitance loss after 10,000 cycles. This paper provides a clean molten salt approach to utilizing both high-rank and low-rank coals for the preparation of capacitive carbons.
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Al2O3 and SiO2 in the coal can be removed by molten carbonate leaching.
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The coal-derived carbon was regulated at the cathode in molten carbonate.
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The coal-derived carbon delivered a specific capacitance of 190 F g−1 at 5 A g−1.
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Both anthracite and lignite can be converted to capacitive carbon in molten salt.