Accelerating ZnO Formation with Hydroxoaluminate for a Stable Alkaline Zn Battery

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Alkaline zinc batteries are cost-effective energy storage solutions but suffer from limited cycle life due to hydrogen evolution, ZnO passivation, and anode shape changes.
• Calcium hydroxide (Ca(OH)2) mitigates shape changes but its low solubility hinders practical application.
• Hydroxoaluminate ions (Al(OH)4-) present a soluble alternative to address these limitations.

Purpose of the Study:

• To investigate hydroxoaluminate ions as a soluble additive for improving alkaline zinc battery performance.
• To evaluate the effect of hydroxoaluminate on zinc anode stability and cycle life.
• To compare hydroxoaluminate with existing additives like Ca(OH)2.

Main Methods:

• Electrochemical kinetic analysis to study interfacial reactions.
• Microstructural characterization to observe anode morphology.
• Battery cycling tests to assess cycle life performance.

Main Results:

• Hydroxoaluminate ions accelerate interfacial zinc oxide (ZnO) formation.
• This accelerated formation effectively suppresses anode shape changes.
• The Zn||NiOOH battery with hydroxoaluminate achieved over 370 cycles at 20% depth of discharge.

Conclusions:

• Hydroxoaluminate ions are a promising soluble additive for enhancing alkaline zinc battery cycle life.
• This additive addresses key limitations of zinc anodes, particularly shape changes.
• The findings pave the way for more durable and practical zinc-based energy storage systems.