Theoretical Studies on the Quantum Capacitance of Two-Dimensional Electrode Materials for Supercapacitors

In recent years, supercapacitors have been widely used in the fields of energy, transportation, and industry. Among them, electrical double-layer capacitors (EDLCs) have attracted attention because of their dramatically high power density. With the rapid development of computational methods, theoretical studies on the physical and chemical properties of electrode materials have provided important support for the preparation of EDLCs with higher performance. Besides the widely studied double-layer capacitance (C-D), quantum capacitance (C-Q), which has long been ignored, is another important factor to improve the total capacitance (C-T) of an electrode. In this paper, we survey the recent theoretical progress on the C-Q of two-dimensional (2D) electrode materials in EDLCs and classify the electrode materials mainly into graphene-like 2D main group elements and compounds, transition metal carbides/nitrides (MXenes), and transition metal dichalcogenides (TMDs). In addition, we summarize the influence of different modification routes (including doping, metal-adsorption, vacancy, and surface functionalization) on the C-Q characteristics in the voltage range of & PLUSMN;0.6 V. Finally, we discuss the current difficulties in the theoretical study of supercapacitor electrode materials and provide our outlook on the future development of EDLCs in the field of energy storage.

Automated summary

In recent years, supercapacitors have been widely used in various fields. Among them, electrical double-layer capacitors (EDLCs) have attracted attention due to their high power density. Theoretical studies on the physical and chemical properties of electrode materials have played an important role in improving the performance of EDLCs. This paper summarizes the recent progress in the theoretical study of quantum capacitance in 2D electrode materials and discusses the impact of different modification routes on the capacitance characteristics.