Interface engineering of template free Zn2V2O7 nanoparticle embedded on Ti3C2Tx MXene hybrid supercapacitor for long term cyclic stability

Pyrovanadate compounds are considered promising electrode candidates for advanced energy storage systems, owing to the superior multivalent redox behavior of vanadium and its inherently high electronic conductivity. In this study, Zn₂V₂O₇ nanoparticles were synthesized via a template-free approach. The high crystallinity of Zn₂V₂O₇, coupled with its indirect band gap characteristics, facilitates enhanced electrochemical performance. The semiconducting transport characteristics of Zn₂V₂O₇ (E g ≈ 2.85 eV) enable a facile charge-transfer mechanism during redox processes, which in turn yields a high specific capacitance of 954 Fg⁻¹ at a current density of 1 Ag⁻¹. In two-dimensional titanium carbide (Ti₃C₂Tₓ) MXenes, the inherent self-stacking of nanosheets, together with the nature of the surface termination groups, critically governs both electronic conductivity and ion transport behavior. In the Zn₂V₂O₇/Ti₃C₂Tₓ composite, the uniform distribution of Zn₂V₂O₇ nanoparticles across the Ti₃C₂Tₓ surface establishes a well-defined interfacial architecture, resulting in a markedly enhanced specific capacitance of 1130 Fg⁻¹ at a current density of 1 Ag⁻¹. The solid-state device based on the Zn₂V₂O₇/Ti₃C₂Tₓ//AC configuration exhibits hybrid supercapacitive behavior, delivering a high areal capacitance of 266 mFcm⁻² at a current density of 2 mAg⁻¹. The fabricated hybrid supercapacitor demonstrates outstanding cycling stability (∼98% capacitance retention, 99% coulombic efficiency after 15,000 cycles at 10 Ag⁻¹) and delivers an energy density of 83.43 mWhkg⁻¹ with a power density of 3300 mW·kg⁻¹ at 2 mA·g⁻¹, underscoring its potential for practical applications.