Glutamate Additive Enables Robust Interphases for Aqueous Zinc Batteries

Researchers from Nankai and Hunan Universities have developed a method to improve the stability of Aqueous Zinc Batteries (AZBs) by forming durable electrode/electrolyte interphase (EEI) layers on both the anode and cathode. The study was published in the journal National Science Review.

AZBs are considered a viable option for large-scale energy storage due to their high theoretical capacities, safety, and environmental compatibility. However, their practical application has been limited by side reactions at the interface between the electrode and electrolyte, which significantly reduce cycle life.

Under the guidance of Professors Zhiqiang Zhu and Fangyi Cheng, the research team addressed this challenge by constructing durable Electrode/Electrolyte Interphase (EEI) layers on both the anode and cathode of the AZB system.

The approach uses the glutamate additive's ability to undergo two distinct self-polymerization processes. At the cathode, a radical-initiated electro-polymerization forms an EEI layer primarily composed of polyglutamic acid. At the anode, a polycondensation reaction leads to a similar EEI layer dominated by polyglutamic acid (PGA).

These EEI layers inhibit the growth of zinc dendrites and the formation of unwanted byproducts while facilitating ionic diffusion and desolvation. This enhances the stability and performance of the battery by protecting the active materials.

The Zn||V₂O₅·nH₂O cells with the glutamate additive demonstrated a high reversible capacity of 387 mA h g⁻¹ at 0.2 A g⁻¹, good rate performance of 171 mAh g⁻¹ at 5 A g⁻¹, and cycling stability of 96.3 % capacity retention after 1,500 cycles at  1 A g^−1.

The interphase-forming additive is compatible with various cathode materials, such as VS₂, VS₄, VO₂, α-MnO₂, β-MnO₂, and δ-MnO₂, making it a promising approach for developing durable and cost-effective aqueous rechargeable batteries.

These advancements could support the development of improved zinc-based batteries for renewable energy storage, particularly for sources like wind and solar power.

Journal Reference:

Geng, Y., et al. (2024) Building electrode/electrolyte interphases in aqueous zinc batteries via self-polymerization of electrolyte additives. National Science Review. doi.org/10.1093/nsr/nwae397