Prospects into the Role of Nanoporous Electrodes for Supercapacitors: Insight into Their Structure and Performance

Electrochemical supercapacitors (SCs) have innumerably met the demand for various energy storage applications by virtue of their excellent reversibility, swift charge–discharge, longer lifespan, and enlarged power densities (PDs). In this realm, designing novel electrode materials with tailored morphologies is essential to improve the SC’s electrochemical performance. This entails introducing nanostructured electrode materials that directly enhance the charge storage capacity of the SC via tunable compositions, dimensions, and morphologies with variable porosities. Thus, reasonable development of homogeneous and heterogeneous three-dimensional (3D) self-supporting electrodes with variable porosities has led to noteworthy improvements in the field of SCs in recent years. Various research studies have also proven that to fabricate a SC with high energy and PD, reduced ion diffusion length, accompanied by greater surface area (SA), is highly necessary, which can be reliably achieved by 3D nanoporous electrodes because of their unique characteristics, which facilitate for increased charge transfer reaction kinetics, accumulating the electrode’s electrical conductivity, and boosting its capacity for energy storage. Henceforth, this paper presents an outline of the fundamental charge storage mechanisms involved in SCs, with special emphasis on the synthesis and electrochemical performance improvement aspects of EDLC, and pseudocapacitive nanoporous electrodes. In conclusion, difficulties and prospects of the role of nanoporous electrodes in SCs are also effectually highlighted.