Co-Doped Vanadium Dioxide Composite Boosts Aqueous Zinc-Ion Battery Performance

A hierarchical modification protocol integrating lattice-level regulation and interface reinforcement markedly enhances the electrochemical performance of vanadium dioxide cathodes for aqueous zinc-ion batteries. In the study, VO2(B) nanobelts were subjected to the hydrothermal co-insertion of sodium and calcium ions, followed by an in-situ coating of poly(3,4-ethylenedioxythiophene) to construct a core-shell composite architecture designated as NCVO/PEDOT.

Aqueous zinc-ion batteries present an attractive option for stationary energy storage systems due to their inherent safety, economical viability, and eco-friendliness. Within this framework, VO2(B) has emerged as a promising cathode candidate because of its high theoretical capacity and open crystallographic tunnels.

The practical implementation of VO2(B) cathodes has nevertheless faced significant obstacles. The material is constrained by narrow interlayer galleries, deficient electrical conduction, progressive structural disintegration during prolonged cycling, and dissolution of the active material into the electrolyte.

To overcome these limitations, the initial hydrothermal co-doping of sodium (Na+) and calcium (Ca2+) ions into the VO2(B) nanobelts was designed to regulate the host lattice. Physical characterization demonstrated that this dual-ion co-doping generates abundant oxygen vacancies within the structure, which serve as additional electroactive sites.

Following the ion insertion, an in-situ coating of poly(3,4-ethylenedioxythiophene) (PEDOT) was applied to enclose the nanobelts. The resulting conductive polymer layer establishes a three-dimensional electron-conductive network that significantly reduces interfacial charge-transfer impedance.

In addition to enhancing electronic conductivity, the physical properties of the core-shell coating contribute to the cathode’s durability. The mechanical flexibility of the PEDOT layer accommodates operational volume changes while effectively suppressing the dissolution of vanadium from the active material.

Electrochemical testing confirmed that the synergistic design substantially improves both charge storage capacity and cycling stability. The optimized NCVO/PEDOT cathode delivered a reversible capacity of 440.1 mAh g−1 at a current density of 0.2 A g−1, and sustained a capacity of 334.1 mAh g−1 under a high rate of 5.0 A g−1.

Long-term cycling evaluations showed that the composite cathode retained 98% of its initial capacity after 1,000 cycles at a current density of 2 A g−1. Under extended testing of 5,000 cycles at 5 A g−1, the electrode maintained 79.6% of its initial capacity, demonstrating structural robustness and interfacial stability for vanadium-based aqueous zinc-ion battery cathodes.

Subject of Research: Vanadium-based cathode materials for aqueous zinc-ion batteries

Article Title: PEDOT coated Na+/Ca2+ co-doped VO2(B) composite material for high-performance aqueous zinc-ion batteries

Article References: Lu, X., Guo, J., Li, S., Li, W., Li, L., Zhang, Z., Chen, S., & Meng, X. (2026). PEDOT coated Na+/Ca2+ co-doped VO2(B) composite material for high-performance aqueous zinc-ion batteries. Ionics. https://doi.org/10.1007/s11581-026-07617-6

Image Credits: AI Generated

DOI: 10.1007/s11581-026-07617-6

Keywords: aqueous zinc-ion batteries, vanadium dioxide, cathode materials, PEDOT coating, ion co-doping, energy storage, cycling stability, oxygen vacancies, PEDOT, coated, co-doped, composite