Thesis Colloquium- Electrode Design and Interface Engineering for Boosting Electrochemical Performance of Aqueous Zinc-based Batteries

Aqueous zinc-based batteries (AZBs) have emerged as promising next-generation energy storage systems due to the abundance of zinc, which expectedly should lower the battery cost. Additionally, Zn-based batteries will be environmentally sustainable and will be safer compared to the alkali metal counterparts based on lithium, sodium and potassium. Leveraging zinc as the anode provides a high theoretical specific capacity (820 mAh g⁻¹) and stable operation in aqueous electrolytes, mitigating risks associated with flammable organic solvents. Although various cathode materials, such as manganese oxides, vanadium-based compounds, and Prussian blue analogs, show potential for enhancing energy density and cycling stability, challenges like zinc dendrite formation, side reactions, and cathode instability remain untackled.¹

The second part of the thesis, comprising of three chapters, focusses on zinc-ion batteries. Here, the critical issues such as dendrite growth, byproduct formation, and cathode dissolution were dealt in detail.⁵ Electrolyte modifications with strategic additives altered the zinc-water solvation sheath [Zn(H₂O)₆], enabling reversible zinc stripping and plating without side reactions. ⁶ Usage of an alloying anode promoted 2D zinc nucleation, ensuring dendrite-free plating and improved sand time.⁷ On the cathode side, intrinsic (such as potassium doping of vanadium oxide) and extrinsic (graphene oxide wrapping) modifications resulted in enhanced conductivity and mitigated dissolution of vanadium-based cathodes like V₂O₅, improving stability and capacity.