Synergistic Redox Modulation in Hollow Mesoporous Frameworks for High-Performance Symmetric and Asymmetric Supercapacitors

Abstract

Transition metal vanadates (TMVs) are promising candidates for high-performance supercapacitor electrode materials owing to their rich redox chemistry, synergistic interactions and cost-effectiveness. However, their practical application is still limited by poor intrinsic conductivity, sluggish ion transport, restricted accessibility of redox-active sites, and structural instability, which collectively hinder the simultaneous attainment of high energy density and long-cycle-life.Herein, an approach based on the “mesopore-confined synergistic redox modulation” is proposed to concurrently enhance conductivity, increase the density of accessible redox-active sites, and improve structural stability. This is achieved by synthesizing a cerium-incorporated cobalt vanadate (CVO@3Ce) hollow mesoporous structure via a glycerol-assisted soft template method. The resulting material, when employed in both aqueous symmetric supercapacitors (ASS) and asymmetric supercapacitors (AAS), delivers energy densities of 34.72 and 47.77 Wh kg^–1, respectively, with capacitance retention of 75.08% (ASS) and 81.20% (AAS) after 10,000 cycles. This work demonstrates an effective strategy for designing high-energy, long-cycle-life electrodematerials for high-performance supercapacitors.