Organic Molecular Intercalated V₃O₇·H₂O with High Operating Voltage for Long Cycle Life Aqueous Zn‐Ion Batteries

Abstract

Abstract V 3 O 7 ·H 2 O (VO) is an attractive cathode material for high‐capacity aqueous Zn‐ion batteries (AZIBs), but it is limited by slow ion mobility and low working platform voltage. Here, a 1,3‐propane diamine (DP)‐intercalated VO with nanoribbon‐assembled thorn flower‐like structure is fabricated by a facile hydrothermal method, noted as VO‐DP. The study shows that the zinc ion diffusion coefficient in VO‐DP (3.1 × 10 −8 cm −2 s −1 ) is five orders of magnitude higher than that of a pure VO counterpart. Auxiliary density functional theory simulation shows that the embedded energy of zinc ions in VO‐DP significantly decreases from 0.24 to −2.5 eV, thus leading to excellent diffusion kinetics and superior rate performance. Benefiting from these unique properties, AZIBs composed of VO‐DP cathodes exhibit high operating voltage (0.89 V), remarkable capacities of 473 mA h g −1 at 0.05 A g −1 , excellent rate capability (144 mA h g −1 at 10 A g −1 ) and long‐term cycling performance (73% capacity retention over 15 000 cycles at 10 A g −1 ).