Cell-nucleus structured electrolyte for low-temperature aqueous zinc batteries

Rechargeable aqueous zinc (Zn) batteries hold great promise for large-scale energy storage, but their implementation is plagued by poor Zn reversibility and unsatisfactory low-temperature performance. Herein, we design a cell-nucleus structured electrolyte by introducing low-polarity 1,2-dimethoxyethane (DME) into dilute 1 M zinc trifluoromethanesulfonate (Zn(OTf)2) aqueous solution, which features an OTf--rich Zn2+-primary solvation sheath (PSS, inner nucleus) and the DME-modulated Zn2+-outer solvation sheath (outer layer). We find that DME additives with a low dosage do not participate in the Zn2+-PSS but reinforce the Zn-OTf- coordination, which guarantees good reaction kinetics under ultralow temperatures. Moreover, DME breaks the original H-bonding network of H2O, depressing the freezing point of electrolyte to-52.4 & DEG;C. Such a cell-nucleus-solvation structure sup-presses the H2O-induced side reactions and forms an anion-derived solid electrolyte interphase on Zn and can be readily extended to 1,2-diethoxyethane. The as-designed electrolyte enables the Zn electrode deep cycling stability over 3500 h with a high depth-of-discharge of 51.3% and endows the Zn||V2O5 full battery with stable cycling over 1000 cycles at-40 & DEG;C. This work would inspire the solvation structure design for low-temperature aqueous batteries.& COPY; 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Researchers have designed an electrolyte structure with 1,2-dimethoxyethane as an additive, which enables rechargeable aqueous zinc batteries to achieve good reaction kinetics and cycling stability at low temperatures.