Cost-effective conversion of “stones” into high-performance capacitor carbon through a solid–solid inorganic chemical reaction

Abstract

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