Superior flexible Zn-ion battery using vanadium oxide nanobelts cathode enables medium temperature range and ultrafast Zn2+ intercalation

The development of flexible and wearable energy storage systems demands zinc-ion batteries with high capacity, mechanical robustness, and long-term electrochemical stability. Vanadium oxide (V 6 O 13 .nH 2 O), with its high theoretical capacity, is a promising cathode material for aqueous and flexible Zn-ion batteries. However, its practical application is hindered by structural instability, vanadium dissolution, and sluggish Zn 2+ reaction kinetics, mainly under mechanical deformation. To address these challenges, nanoscale engineering has emerged as an effective strategy to improve both electrochemical performance and mechanical stability. Herein, monoclinic-phase V 6 O 13 .nH 2 O nanobelts are synthesized as robust cathodes, enabling ultrafast Zn 2+ kinetics, a medium operating temperature range, and excellent structural stability suitable for flexible battery configurations. The experimental results demonstrated an outstanding electrochemical performance of the V 6 O 13 .nH 2 O nanobelts cathode, delivering a high specific capacity of 400 mAh g −1 at 0.1 A g −1 and retaining ∼95% capacity after 500 cycles at 1 A g −1 at different temperatures. Furthermore, the coin cell configuration maintains 79% capacity after 1500 cycles, whereas the flexible battery exhibits 78% capacity retention after 600 cycles at 10 A g −1 . This work highlights vanadium-based cathode design in overcoming limitations of flexible Zn-ion batteries and provides valuable insights into the electrochemical mechanisms governing high-performance electrodes.