Optimize Lithium Deposition at Low Temperature by Weakly Solvating Power Solvent

For lithium (Li) metal batteries, the decrease in operating temperature brings severe safety issues by more disordered Li deposition. Here, we demonstrate that the solvating power of solvent is closely related to the reversibility of the Li deposition/stripping process under low-temperature conditions. The electrolyte with weakly solvating power solvent shows lower desolvation energy, allowing for a uniform Li deposition morphology, as well as a high deposition/stripping efficiency (97.87 % at -40 degrees C). Based on a weakly solvating electrolyte, we further built a full cell by coupling the Li metal anode with a sulfurized polyacrylonitrile electrode at a low anode-to-cathode capacity ratio for steady cycling at -40 degrees C. Our results clarified the relationship between solvating power of solvent and Li deposition behavior at low temperatures.

Automated summary

This study finds that the solvating power of solvent is closely related to the behavior of lithium deposition at low temperatures in lithium metal batteries. A solvent with weak solvating power enables higher deposition/stripping efficiency and uniform deposition morphology. By designing appropriate electrolyte and electrode materials, stable cycling at low temperatures can be achieved.