Achieving Both High Voltage and High Capacity in Aqueous Zinc-Ion Battery for Record High Energy Density

In this work, a high-voltage output and long-lifespan zinc/vanadium oxide bronze battery using a Co_0.247V₂O₅⋅0.944H₂O nanobelt is developed. The high crystal architecture could enable fast and reversible Zn²⁺ intercalation/deintercalation at highly operational voltages. The developed battery exhibits a high voltage of 1.7 V and delivers a high capacity of 432 mAh g⁻¹ at 0.1 A g⁻¹. The capacity at voltages above 1.0 V reaches 227 mAh g⁻¹, which is 52.54% of the total capacity and higher than the values of all previously reported Zn/vanadium oxide batteries. Further study reveals that, compared with the pristine vanadium oxide bronze, the absorption energy for Zn²⁺ increases from 1.85 to 2.24 eV by cobalt ion intercalation. Furthermore, it also shows a high rate capability (163 mAh g⁻¹ even at 10 A g⁻¹) and extraordinary lifespan over 7500 cycles, with a capacity retention of 90.26%. These performances far exceed those for all reported zinc/vanadium oxide bronze batteries. Subsequently, a nondrying and antifreezing tough flexible battery with a high energy density of 432 Wh kg⁻¹ at 0.1 A g⁻¹ is constructed, and it reveals excellent drying and freezing tolerance. This research represents a substantial advancement in vanadium materials for various battery applications, achieving both a high discharge voltage and high capacity.