Cost-Effective Conversion of "Stones" into High-Performance Capacitor Carbon through Solid-Solid Inorganic Chemical Reaction

Abstract

Supercapacitors are highly sought after by the expanding new energy industry due to their advantages of high power and long life. However, porous carbon, a crucial electrode material, has been extremely expensive. As a result, the supercapacitor manufacturing industry has developed a strong demand for a new, low-cost method of preparing capacitor carbon. This study reports for the first time a novel method of producing high-performance capacitive carbon from the ultra-low-cost raw materials CaCO3 (the primary stone component) and CaC2 (also referred to as electrical stone), which is accomplished by ball milling the two to cause a solid-solid inorganic chemical reaction. The specific surface area attained by this approach reaches 1000 m2 g-1 due to the template function of the CaO generated in situ during the reaction, which is the highest level reported for CaC2-derived carbon. The capacitive carbon performs well in both aqueous and organic electrolytes, with a Coulombic efficiency of approximately 100%. It outperforms the commercial capacitive carbon YP50F, even when made on a kilogram scale. This advancement dramatically reduces the cost of large-scale use of porous carbon in supercapacitors, establishing a long-term relationship between carbon neutrality and clean energy development.