A Reversible Four-electron Sn Metal Aqueous Battery

Sn is a promising metal anode for aqueous batteries due to its dendrite-free plating, large hydrogen evolution overpotential, and high theoretical capacity with up to four-electron redox per Sn atom. However, practically achieving the theoretical capacity for Sn remains challenging, with only limite...

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Bibliographic Details
Published in:ChemRxiv 2024-01
Main Authors: Wang, Jianbo, Catalina, Sofia K., Jiang, Zhelong, Xu, Xin, Zhou, Qin Tracy, Chueh, William C., Mefford, J. Tyler
Format: Article
Language:English
Subjects:
Anodes
Chemistry
Electrochemistry
Energy
Energy Storage
Hydrogen evolution
Inorganic Chemistry
Plating
Online Access:Get full text
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Summary:Sn is a promising metal anode for aqueous batteries due to its dendrite-free plating, large hydrogen evolution overpotential, and high theoretical capacity with up to four-electron redox per Sn atom. However, practically achieving the theoretical capacity for Sn remains challenging, with only limited cell energy densities demonstrated thus far. We validate a kinetically asymmetric [Sn(OH)6]2-/Sn redox pathway involving a direct four-electron plating and a stepwise 2+2 electron stripping through a [Sn(OH)3]- intermediate, which decreases the Coulombic efficiency (CE) by shuttling to the cathode and promoting chemical self-discharge. By using ion-selective membranes to suppress [Sn(OH)3]- crossover, we demonstrate Sn-Ni full cells with high round-trip efficiency (~80%) and energy density (143.1 Wh L-1). The results provide key understandings to the tradeoffs in engineering reversible multi-electron metal anodes and define a new benchmark for practical energy density that exceeds Sn-based aqueous batteries to date.
ISSN:2573-2293
DOI:10.26434/chemrxiv-2024-475km