Vanadium-based oxides stand out as electrode materials with substantial commercialization potential for aqueous zinc-ion batteries owing to their eco-friendliness and remarkable energy density. Nevertheless, poor capacity retention and electrical conductivity impede their further development in wearable devices. Herein, synthesize CaVO₂-polyvinylpyrrolidone nanobelts through a facile hydrothermal strategy. At a current density of 0.5 A/g, the assembled cells provide a discharge capacity of 334 mAh/g. Meanwhile, the button batteries also maintain a discharge capacity of 279 mAh/g at an environmental temperature of 0 ℃ (1.0 A/g). The flexible pouch devices further present outstanding mechanical stability under various folding states.

Layered vanadium oxides are desired cathode materials due to their multielectron redox reactions. However, their further development has been limited by the low electrical conductivity and unstable crystal structure. Herein, we synthesize V₂O₅ microspheres with oxygen-rich vacancies by Mo doping strategy. The oxygen vacancies provide preferential adsorption sites for Zn ions, thereby decreasing the ionic migration barrier within the host framework. The Zn//Mo-V₂O₅ batteries achieve a specific capacity of 502.5 mAh·g⁻¹ at 0.2 A·g⁻¹ and retain 433.2 mAh·g⁻¹ after 100 times cycling. Moreover, they possess 2000 times cycling life with a retention rate of 100% at a low temperature of 0 °C (1 A·g⁻¹). It is believed that the reliable Mo-doping approach will provide new insights for high-performance energy storage systems.

Ammonium vanadate has been extensively studied as a promising electrode material for energy-storage devices with the tunable layered structure. Nevertheless, the excessive extraction of NH₄⁺ leads to the irreversible structure degradation and capacity decrease in cycling process. In this work, we introduce Ca²⁺ into the NH₄V₄O₁₀ samples via a simple hydrothermal route, which stabilizes the interlayer structures. At a current density of 0.2 A·g⁻¹, the assembled cells possess a discharge specific capacity of 547.9 mAh·g⁻¹. In addition, they still operate steadily at diverse temperatures from 20 to –20 °C. The soft-packaged devices also present remarkable mechanical properties under various folding degrees.

The development of bifunctional catalysts enables the simultaneous operation of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the same electrolyte. It is feasible to design high-performance catalysts by the addition of impurity atoms and the construction of composition. Herein, Fe-Ni₃P/Fe-CoP₃ nanostructures are obtained using metal–organic framework (MOF) as the precursor. It shows an overpotential of 71.7 mV (10 mA/cm²) for HER and 263.3 mV (50 mA/cm²) for OER under alkaline condition. Moreover, it also presents an OER overpotential of only 325.3 mV at the current densities of 1.5 A/cm². Using the catalyst as electrodes, the water electrolysis device provides a voltage of 1.566 V at 50 mA/cm². Density functional theory calculations reveal that the introduction of iron atoms and the presence of heterogeneous structures optimize the hydrogen adsorption energy.

It is important to develop economical and durable electrocatalysts for sustainable energy conversion technology. However, the current catalysts still suffer from insufficient hydrogen adsorption energy. Herein, we report a kind of novel bi-phosphide catalyst through constructing heterogeneous structures and cation doping. The obtained sample delivers an outstanding hydrogen evolution reaction (HER) performance at all pH range. As oxygen evolution reaction (OER) electrocatalyst, Fe-CoP@Ni₂P samples show an overpotential of 237 mV at 50 mA·cm⁻² in alkaline solution. For electrolysis of water, Fe-CoP@Ni₂P catalysts deliver a cell voltage of 1.59 V at 50 mA·cm⁻² and long durability. Furthermore, density functional theory (DFT) calculation further confirms that the doped heterostructure promotes Gibbs free energy for hydrogen adsorption. And the significant increase in the density of total states (DOS) also enhances the catalytic activity of HER.