Sulfuryl Chloride as a Functional Additive towards Dendrite-Free and Long-Life Li Metal Anodes
With ultrahigh theoretical specific capacity and the lowest redox potential, lithium (Li) metal is regarded as the most promising anode material for electrochemical energy storage field. However, the formation of undesired Li dendrites severely hinders its practical application in Li metal batteries (LMBs), when repeating the Li plating/stripping processes. Herein, we report that an optimal amount (2%) of sulfuryl chloride (SO2Cl2) could highly improve the electrochemical performance of Li metal anode in ester-based electrolyte by in-situ forming a stable inorganic protective layer on its surface to strengthen the native solid electrolyte interphase (SEI). The LiCl-rich SEI layer is beneficial for suppressing the growth of Li dendrites as well as accelerating the migration of Li ions. As a result, a greatly enhanced Coulombic efficiency (CE) of 95% after 150 cycles in Li||Cu cell and a long-term cycling life over 1200 h with low and stable overpotential of ~40 mV in Li||Li symmetrical cell have been achieved. Therefore, this work provides a new and promising strategy for speeding up the practical application of Li anode in LMBs.