Zinc‐Ion Hybrid Supercapacitors Employing Acetate‐Based Water‐in‐Salt Electrolytes

Autor: Jin Han, Alessandro Mariani, Maider Zarrabeitia, Zenonas Jusys, R. Jürgen Behm, Alberto Varzi, Stefano Passerini
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Small, 18 (31), Art.-Nr.: 2201563
ISSN: 1613-6810
1613-6829
Popis: Halide-free, water-in-salt electrolytes (WiSEs) composed of potassium acetate (KAc) and zinc acetate (ZnAc$_2$) are investigated as electrolytes in zinc-ion hybrid supercapacitors (ZHSs). Molecular dynamics simulations demonstrate that water molecules are mostly non-interacting with each other in the highly concentrated WiSEs, while “bulk-like water” regions are present in the dilute electrolyte. Among the various concentrated electrolytes investigated, the 30 m KAc and 1 m ZnAc$_2$ electrolyte (30K1Zn) grants the best performance in terms of reversibility and stability of Zn plating/stripping while the less concentrated electrolyte cannot suppress corrosion of Zn and hydrogen evolution. The ZHSs utilizing 30K1Zn, in combination with a commercial activated carbon (AC) positive electrode and Zn as the negative electrode, deliver a capacity of 65 mAh g$^{−1}$ (based on the AC weight) at a current density of 5 A g$^{−1}$. They also offer an excellent capacity retention over 10 000 cycles and an impressive coulombic efficiency (≈100%).
Databáze: OpenAIRE
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