RbF as a Dendrite-Inhibiting Additive in Lithium Metal Batteries.

Lithium metal is considered to be one of the most potential anode materials on account of its high theoretical specific capacity and lowermost electrochemical potential. Nevertheless, the critical challenges of dendrite growth and low Coulombic efficiency (CE) of the lithium metal anode during cycling prevent the commercial application of the lithium metal battery. Herein, rubidium fluoride (RbF) as additives is utilized to inhibit the lithium dendrite growth. Benefiting from the stronger electropositive property of Rb+, it can adsorb on the surface of protuberances during the lithium deposition process, form an electrostatic shielding field of the surface, and guide the uniform deposition of Li+. The CE can maintain above 90% with the additives of RbF in the carbonate electrolyte. Besides that, RbF improves the cycle life and decreases the polarization, a stable cycling performance of more than 1000 h is obtained, and the overvoltage is controlled below 100 mV in the cycling test of Li∥Li symmetrical cells at 0.5 mA cm-2. The addition of RbF offers a feasible way for the development of lithium metal batteries (LMBs) in the future.