Halogen-based functionalized chemistry engineering for high-performance supercapacitors

Abstract

Supercapacitors (SCs) are rated as the foremost efficient devices bridging the production and consumption of renewable energy. To address the ever-increasing energy requirements, it is indispensable to further develop high-performance SCs with merits of high energy-density, acceptable price and long-term stability. This review highlights the recent advances on halogen-based functionalized chemistry engineering in the state-of-the-art electrode system for high-performance SCs, primarily referring to the doping and decoration strategies of F, Cl, Br and I elements. Due to the discrepancy of electronegativity and atomic radius, the functionalization of each halogen element endows the substrate materials with different physicochemical properties, including energy bandgap structure, porosity distribution and surface affinity. The principle of halogen embedment into host materials by precisely controlling ionic adsorption and electronic structure is presented. And, the vital perspectives on the future challenges of halogen functionalization are also discussed. This work aims to deepen the understanding of halogen-based functionalized strategies to motivate further research for the development of high-performance SCs, and it also provides a prospect for exploring new material modification methods for electrochemical energy storage. This review highlights the recent advances on halogen-based functionalized chemistry engineering in the state-of-the-art electrode system for high-performance supercapacitors (SCs), primarily referring to the doping and decoration strategies of F, Cl, Br and I elements.