Advances in Anion-Intercalated Layered Double Hydroxides for Supercapacitors: Study of Chemical Modifications and Classifications

Abstract

Hybrid materials-based electrochemical supercapacitors (SCs) possessing improved energy density (ED), enhanced stability, large porosity, and accessible surface area, are accomplished better attention as promising energy storage devices. SCs also demonstrate excellent specific capacitance (Cs) across various current densities, increased capacitance, and higher cell voltages, all contributing to improved ED. Layered double hydroxides (LDHs), with their anionic exchange capabilities and laminar structure, offer significant potential for boosting charge transfer in SCs. This review provides a comprehensive overview of recent advances in anion-based LDHs, discussing their storage mechanisms, chemical modifications, and classification based on interlayer anions. The roles of different anions, including monovalent, divalent, and polyoxometalates, in enhancing storage properties are examined. In addition, challenges, future research directions, and practical perspectives for anion-storing LDHs are also presented. Hence, this review provides a concise overview of anion-based LDHs for SCs, highlighting their potential significance in energy storage applications.