Porous zeolitic imidazolate framework-67@CeVO4 hybrid composite with enhanced ion diffusion kinetics for high-performance energy storage devices

Abstract

The seamless integration of energy conversion and storage remains a critical challenge for the advancement of high-performance electrochemical energy storage systems. In this work, a ZIF-67@CeVO₄ hybrid composite was prepared via a hydrothermal method, integrating the high surface area and porous architecture of a metal–organic framework with the electroactive properties of a metal vanadate to achieve synergistic charge storage behaviour. Structural and morphological characterizations confirm the intimate interfacial contact between ZIF-67 and CeVO₄ within a porous host matrix, which promotes efficient electron transport and ion diffusion. ZIF-67@CeVO₄ possesses a high specific capacitance of 611.4 F g⁻¹ at 1 A g⁻¹, a low charge-transfer resistance of 3.7 Ω, and exceptional cycling stability, with 97.6% capacitance retention after 5000 cycles. This demonstrates that the composite exhibits rapid electrochemical kinetics and high structural stability. Furthermore, an asymmetric supercapacitor device assembled using the ZIF-67@CeVO₄-ASC electrode exhibits a specific capacitance of 64.5 F g⁻¹, an energy density of 22.9 W h kg⁻¹, a power density of 1917.2 W kg⁻¹, a coulombic efficiency of 99.1%, and outstanding cycling stability, retaining 95.6% of its initial capacity after 5000 cycles. This work presents a viable strategy for designing high-performance electrode materials and provides insights into their future optimization for scalable, high-energy asymmetric supercapacitor devices in practical energy storage applications.