Molten salt synthesis of porous carbon and its application in supercapacitors: A review

Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area, low price, and stable physicochemical properties. Considerable research efforts have been devoted to the development of novel synthesis strategy for the preparation of porous carbon materials in recent years. In particular, molten salt strategy represents an emerging and promising method, whereby it has shown great potential in achieving tailored production of porous carbon. It has been proved that the molten salt-assisted production of carbon via the direct carbonization of carbonaceous precursors is an effective approach. Furthermore, with the incorporation of electrochemical technology, molten salt synthesis of porous carbon has become flexible and diversiform. Here, this review focuses on the mainstream molten salt synthesis strategies for the production of porous carbon materials, which includes direct molten salt carbonization process, capture and electrochemical conversion of CO2 to value-added carbon, electrochemical exfoliation of graphite to graphene-based materials, and electrochemical etching of carbides to new-type carbide-derived carbon materials. The reaction mechanisms and recent advances for these strategies are reviewed and discussed systematically. The morphological and structural properties and capacitive performances of the obtained carbon materials are summarized to reveal their appealing points for supercapacitor applications. Moreover, the opportunities and challenges of the molten salt synthesis strategy for the preparation of carbon materials are also discussed in this review to provide inspiration to the future researches.