Mitigating hydrogen evolution reaction and corrosion of zinc in electrically rechargeable zinc-air batteries using nanofluid electrolytes

• Published in: Journal of energy storage Vol. 81; p. 110457
• Main Authors: Subramaniam, Thiruvenkatam, Idris, Mustapha Balarabe, K.S., Suganthi, K.S., Rajan, S., Devaraj
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.03.2024
• Subjects: Aqueous electrolyte; HER; Modified electrolyte; Nanofluid electrolyte; Zinc corrosion; Zinc-air battery; Modified electrolyte; Zinc corrosion; Nanofluid electrolyte; Aqueous electrolyte; HER; Zinc-air battery
• ISSN: 2352-152X
• DOI: 10.1016/j.est.2024.110457

Among various metal-air batteries, zinc-air batteries (ZABs) have received tremendous attention owing to their abundant resources, cost-free fuel from the atmosphere and ease of fabrication. The performance of ZABs depends on the bifunctional electrocatalyst deployed at the air-cathode and the hydrogen evolution reaction (HER) occurring at the anode. While the rate of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) improve the performance of ZAB, HER causes zinc corrosion and thereby affects the performance of ZAB. The corrosion of zinc is attributed to the fact that HER is thermodynamically favoured since the standard reduction potential of zinc is more negative than hydrogen. Herein, the onset and overpotential of HER are increased by the uniform dispersion of metal oxide nanoparticles in the native electrolyte (6 M KOH), thereby reducing zinc corrosion. Dispersion of 0.1 wt% of SiOx or ZnO nanoparticles increases the HER overpotential to 547 and 679 mV, respectively. The microscopic investigations confirm the inhibition of corrosion and dendritic growth of zinc. Besides these, nanofluid electrolytes enhance the kinetics of ORR and OER, thereby improving the performance of electrically rechargeable ZABs. Also, nanofluid electrolytes are stable over three months. [Display omitted] •Electrically rechargeable zinc-air batteries (erZABs) are designed rationally using nanofluid (NF) electrolytes.•NF electrolytes impede the parasitic reaction, hydrogen evolution.•NF electrolytes inhibit the corrosion and dendritic growth of zinc.•NF electrolytes promote the kinetics of key reactions, oxygen reduction and oxygen evolution.•NF electrolytes improve the performance of erZABs.