Atomic Layer-Deposited ZnO Layer on Hydrated Vanadium Dioxide Cathodes against Vanadium Dissolution for Stable Zinc Ion Batteries

Abstract

Vanadium oxides are considered one of the most promising cathode materials for aqueous zinc ion batteries. However, vanadium dissolution caused by undesirable side reactions greatly decreases the structure stability and capacity retention. In this work, an atomic layer-deposited ZnO layer is uniformly coated on a hydrated vanadium dioxide nanosheet array cathode, which effectively suppresses the vanadium dissolution and side reactions. The resultant cathode displays improved capacity retentions from 74 to 89% after 100 cycles at 0.5 A g −1 and from 29 to 71% after 990 cycles at 5 A g −1 . Moreover, the structural evolution after electrochemical cycling of the cathode is thoroughly investigated to reveal the protection mechanism. The atomic layer deposition strategy may also be extended to the protection of other cathodes that suffer from the dissolution issue with wide choices of the protection layer materials.

Current Challenges and Advanced Design Strategy of Vanadium Dioxide Cathode for Low‐Cost Aqueous Zinc Metal Battery

“…Shuai et al recently prepared ZnO@VO 2 · x H 2 O with uniform and ultrathin ZnO layer by the atomic layer deposition technology with the advantage of easy control of thickness (Figure 8e). [ 35 ] This artificial interface layer not only allows the Zn 2+ ion to pass through, but also prevents unnecessary side reactions at the electrode interface and inhibits the dissolution of vanadium (Figure 8f). The O and Zn vacancy defects in ZnO also provide an ion diffusion pathway to produce significantly enhanced performance (Table 1).…”

“…e) Digital images of suppressing vanadium immersed in the electrolyte and f ) TEM of VO 2 @ZnO. Reproduced with permission [35]. Copyright 2022, The American Chemical Society.…”

Mitigating cathodic dissolution through interfacial water masking to enhance the longevity of aqueous zinc–ion batteries

“…Numerous researchers have been exploring the strategy of interface water masking agents (IWMAs) from the perspective of cathodes and electrolytes. Creating an artificial solid electrolyte interface (e.g., poly (3,4-ethylenedioxythiophene), 15 HfO 2 , 16 ZnO, 17 polyaniline, 18 Ti 3 C 2 T x MXene 19 ) on the cathode surface has emerged as an effective protection approach. By forming a surface passivation layer as a barrier between the cathode and electrolyte, this strategy mitigates the entry of water molecules into the electrode material, effectively inhibiting undesirable interfacial reactions and preventing the dissolution of active chemicals in the electrolyte.…”

Cobalt Ion-Stabilized VO2 for Aqueous Ammonium Ion Hybrid Supercapacitors

“…(ii) Electrolyte additive strategy. 45 Mei and co-workers proposed a hybrid electrolyte (Zn(OTf) 2 -TEP/H 2 O), which is made from zinc triflate salt in triethyl phosphate and an aqueous solvent and has an excellent ability to inhibit vanadium dissolution. 46 However, the above two types of strategies have high costs, complex preparation, and unclear mechanisms of the action of electrolyte additives; therefore, they are not the optimal solutions.…”

“…Xu effectively suppressed the dissolution and side reactions of vanadium by depositing thin layers of ZnO on VO 2 nanosheet arrays through atomic layer deposition. (ii) Electrolyte additive strategy . Mei and co-workers proposed a hybrid electrolyte (Zn­(OTf) 2 -TEP/H 2 O), which is made from zinc triflate salt in triethyl phosphate and an aqueous solvent and has an excellent ability to inhibit vanadium dissolution .…”