Unveiling the Mysteries: Acetonitrile’s Dance with Weakly-Solvating Electrolytes in Shaping Gas Evolution and Electrochemical Performance of Zinc-ion Batteries
[ 1 ] Instytut Chemii i Elektrochemii Technicznej, Wydział Technologii Chemicznej, Politechnika Poznańska | [ P ] employee
2024
scientific article
english
- electrolyte additive
- gas evolution suppression
- Zn-dendrite mitigation
- Vanadium dissolution alleviation
- Zn metal anode
- aqueous Zn-metal batteries
EN Aqueous Zn-metal battery (AZMB) is a promising candidate for future large-scale energy storage with commendable capacity, exceptional safety characteristics, and low cost. Acetonitrile (AN)has been widely used as an effective electrolyte constituent to improve AZMBs’ performance. However, its functioning mechanisms remain unclear. In this study, we unveiled the critical roles of AN in AZMBs via comparative in-situ electrochemical, gaseous, and morphological analyses. Despite its limited ability to solvate Zn ions, AN modulated Zn-ion solvation sheath with increased anions and decreased water, achieving a weakly-solvating electrolyte. As a result, the Zn||Zn cell with AN addition exhibited 63 times longer cycle life than cell without AN and achieved a 4Ahcm-2 accumulated capacity with no H2 generation. In V2O5||Zn cells, for the first time, AN suppressing CO2 generation, elevating CO2-starting voltage from 2→2.44 V (H2: 2.43→2.55 V) was discovered. AN-impeded transit and Zn-side deposition of dissolved vanadium ions, known as “crosstalk,” ameliorated inhomogeneous Zn deposition and dendritic Zn growth. At last, we demonstrated an AN-enabled high-areal-capacity AZMB (3.3 mAh cm-2) using high-mass-loading V2O5 cathode (26 mg cm-2). This study shed light on the strategy of constructing fast-desolvation electrolytes and offered insights for future electrolyte accommodation for high-voltage AZMB cathodes.
08.03.2024
e202402206-1 - e202402206-25
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