Authors:

Chunge Li

Date Created:

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About Paper:

The ongoing transition to renewable energy demands inexpensive and safe batteries for efficient energy storage. Aqueous Zinc Ion Batteries (AZIBs) present a promising solution with their high theoretical energy capacity, low potential, high material abundance and inherent safety of the aqueous electrolyte. However, the parasitic hydrogen evolution reaction (HER) that occurs during the charging process of AZIBs, where zinc metal is deposited at the anode, limits their lifetime. The HER creates a local alkaline environment for side reactions such as zinc hydroxide precipitations and uneven deposition or dendrite growth due to bubble formations. This research aims to understand the kinetics of HER that occurs concurrently with the zinc deposition in AZIBs with weakly acidic or neutral electrolytes. Here, we used the rotating ring-disk electrode (RRDE) method with an iridium oxide (IrOx) ring electrode for pH detection and a platinum ring for hydrogen collection. We captured the local pH change near the zinc working electrode and the hydrogen production during zinc deposition non-intrusively. Combined with the hydrodynamics of the RRDE system, this technique allowed for quantitative determination and comparison of the percent of current that is attributed to HER under well-defined mass transport conditions. Our findings provide insight into the mechanisms of HER coupled with zinc deposition and guidance for designing HER-suppressing modifications to enhance the cyclability of AZIBs. Keywords: [no keywords provided]

Source:

Purdue University / 2024

Topics:

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Co-authors:

Chunge Li