Tailoring the metal electrode morphology via electrochemical protocol optimization for long-lasting aqueous zinc batteries

Aqueous zinc metal batteries are a viable candidate for cost-effective energy storage. However, the cycle life of the cell is adversely affected by the morphological evolution of the metal electrode surface upon prolonged cycling. Here, we investigate different electrochemical protocols to favour the formation of stable zinc metal electrode surface morphologies. By coupling electrochemical and optical microscopy measurements, we demonstrate that an initial zinc deposition on the metal electrode allows homogeneous stripping and plating processes during prolonged cycling in symmetric Zn||Zn cell. Interestingly, when an initially plated zinc metal electrode is tested in combination with a manganese dioxide-based positive electrode and a two molar zinc sulfate aqueous electrolyte solution in coin cell configuration, a specific discharge capacity of about 90 mAh g(-1) can be delivered after 2000 cycles at around 5.6 mA cm(-2) and 25 degrees C. Long-lasting zinc metal electrodes are crucial in developing commercial zinc-based batteries. Here, the authors investigate the different morphology evolution between the stripping and plating process and propose electrochemical protocols to prolong the lifespan of zinc anodes.

Automated summary

Aqueous zinc metal batteries are a cost-effective energy storage option, but the morphological evolution of the metal electrode surface can affect the cycle life of the battery. By studying different electrochemical protocols, stable zinc metal electrode surface morphologies can be achieved. Initial zinc deposition on the electrode allows for homogeneous stripping and plating processes. The combination of an initially plated zinc electrode, a manganese dioxide-based positive electrode, and a specific electrolyte solution can result in long cycle life and high discharge capacity.