Electrolyte additive enabled low temperature lithium metal batteries

One of the key challenges in the development of energy storage devices such as batteries is the ability to operate efficiently in cold environments. Here, we demonstrate a dioxolane-based electrolyte with dimethyl sulfoxide (DMSO) as an additive, which helps the nucleation of lithium and the construction of a robust solid electrolyte interphase (SEI) layer on the lithium metal electrode under extremely cold conditions. Cryogenic transmission electron microscopy and X-ray photoelectron spectroscopy are utilized to thoroughly characterize the microstructure and composition of the SEI. A series of electrochemical tests are conducted at temperatures as low as −80 °C, and the results demonstrate the SEI is resilient to the stripping and plating cycles of lithium metal in cold environments. Moreover, lithium metal batteries with the DMSO added electrolyte can deliver a discharge capacity of 51 mA h g⁻¹ at −40 °C at a current rate of 0.2C. This work provides fundamental insights into the development of lithium metal batteries in harsh environments.