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.

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.