image: Schematic illustration of the function mechanism of glutamate additives for aqueous zinc batteries.
Credit: ©Science China Press
Researchers from Hunan University and Nankai University have made advancement in the field of aqueous zinc batteries (AZBs). Published in National Science Review, their study introduces a novel approach to construct robust electrode/electrolyte interphase (EEI) layers on both the cathode and anode of AZBs, greatly enhancing battery stability.
AZBs are seen as a promising option for large-scale energy storage due to their inherent safety, environmental benefits, and high theoretical capacities. However, their practical application has been hindered by undesirable side reactions at the electrode/electrolyte interface, leading to short cycle life. Led by Professor Zhiqiang Zhu and Professor Fangyi Cheng, the research team solved this issue by using glutamate additives to build EEI layers on both electrodes of AZBs.
The genius of this strategy lies in the two different self-polymerization processes of the glutamate additive on the cathode and anode. On the cathode, it undergoes a radical-initiated electro-polymerization process, resulting in an EEI layer dominated by electropolymerized polyglutamic acid. On the anode, it polymerizes via a polycondensation reaction, forming a robust EEI layer dominated by polycondensation-induced PGA. These EEI layers efficiently suppress the loss of active materials, accumulation of by-products, and growth of Zn dendrite, while also facilitating ionic diffusion and desolvation. Consequently, the Zn||V2O5·nH2O cells with glutamate additive demonstrated outstanding electrochemical performance, including a high reversible capacity of 387 mA h g−1 at 0.2 A g−1, superior rate performance of 171 mAh g−1 at 5 A g−1, and excellent cycling stability of 96.3% capacity retention after 1500 cycles at 1 A g−1.
This interphase-forming additive works well with various cathode materials, such as VS2, VS4, VO2, α-MnO2, β-MnO2, and δ-MnO2, opening up new doors for developing durable and cost-effective aqueous rechargeable batteries.
The findings would promote building better aqueous Zn-based batteries promising for clean and renewable energy storage from intermittent sources like solar and wind power.