Recent Advances and Challenges in Hybrid Supercapacitors Based on Metal Oxides and Carbons

Abstract

Hybrid supercapacitors (HSCs) are a novel type of supercapacitor composed of battery-type electrodes and capacitor-type electrodes, which have directly transformed the global energy landscape. On one hand, they can replace clean energy sources that are heavily dependent on climatic conditions in specific regions, thereby enhancing the effective utilization of intermittent energy sources. On the other hand, with their high energy density akin to secondary batteries and the long lifespan and high power density characteristic of supercapacitors, they perfectly bridge the gap between secondary batteries and supercapacitors. This article reviews the fundamental energy storage principles of HSCs and highlights the latest optimization strategies for HSCs based on transition metal oxides (TMOs) and carbon over the past two years. These strategies include heteroatom doping, heterostructured materials, nanocomposites, and metal–organic frameworks (MOF). Finally, prospects on future research directions of HSCs are discussed.