A weakly solvating electrolyte towards practical rechargeable aqueous zinc-ion batteries.

Shi, Xin; Xie, Jinhao; Wang, Jin; Xie, Shilei; Yang, Zujin; Lu, Xihong · Nat Commun · 2024

basic_science · Level V

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Abstract

Structure deterioration and side reaction, which originated from the solvated H<sub>2</sub>O, are the main constraints for the practical deployment of both cathode and anode in aqueous Zn-ion batteries. Here we formulate a weakly solvating electrolyte to reduce the solvating power of H<sub>2</sub>O and strengthen the coordination competitiveness of SO<sub>4</sub><sup>2-</sup> to Zn<sup>2+</sup> over H<sub>2</sub>O. Experiment results and theoretical simulations demonstrate that the water-poor solvation structure of Zn<sup>2+</sup> is achieved, which can (i) substantially eliminate solvated-H<sub>2</sub>O-mediated undesirable side reactions on the Zn anode. (ii) boost the desolvation kinetics of Zn<sup>2+</sup> and suppress Zn dendrite growth as well as structure aberration of the cathode. Remarkably, the synergy of these two factors enables long-life full cells including Zn/NaV<sub>3</sub>O<sub>8</sub>·1.5H<sub>2</sub>O, Zn/MnO<sub>2</sub> and Zn/CoFe(CN)<sub>6</sub> cells. More importantly, practical rechargeable AA-type Zn/NVO cells are assembled, which present a capacity of 101.7 mAh and stability of 96.1% capacity retention after 30 cycles at 0.66 C.