Cyclic voltammetry of hybrid supercapacitors: A characterization review

Supercapacitors (SCs), including electric double-layer capacitors (EDLCs), pseudo-capacitors, and hybrid capacitors, are vital for energy storage. EDLCs use porous carbon materials, while pseudo-capacitors rely on oxide redox reactions. Hybrid SCs combine these methods to enhance cell potential and energy density. This review examines the electrochemical characterization of hybrid SCs, focusing on cyclic voltammetry (CV). It discusses material selection, cell setup, initial CV results, and full-cell CV characterization, emphasizing curve shape, voltage-current behavior, diffusion, and performance. The review also explores the impact of mechanical stress on CV and highlights the need for standardized CV protocols. Although hybrid SCs offer rapid charging and high energy storage, CV research from 2019 to 2024 remains limited and sometimes contradictory. The review underscores CV’s role in understanding hybrid SCs and suggests future research to address gaps and improve optimization.