A bifunctional electrolyte additive for separator wetting and dendrite suppression in lithium metal batteries. (20th April 2018) - Zheng, Hao
Abstract: Reformulation of electrolyte systems and improvement of separator wettability are vital to electrochemical performances of rechargeable lithium (Li) metal batteries, especially for suppressing Li dendrites. In this work we report a bifunctional electrolyte additive that improves separator wettability and suppresses Li dendrite growth in Li metal batteries. A triblock polyether (Pluronic P123) is added as an additive into a commonly used carbonate-based electrolyte. It is found that addition of 0.2–1% (by weight) P123 into the electrolyte can effectively enhance the wettability of polyethylene separator. More importantly, the adsorption of P123 on Li metal surface can act as an artificial solid electrolyte interphase layer and suppress the growth of Li dendrites. A smooth and dendrite-free Li morphology can be achieved in the electrolyte with 0.2% P123. The Li||Li symmetric cells with the 0.2% P123-containing electrolyte exhibit a relatively long cycling stability at high current densities of 1.0 and 3.0 mA cm −2 . Graphical abstract: The cycling stability of the symmetrical Li cells using the electrolyte of 1 M LiPF6 /PC with 0.2% P123 is much better than that without P123 at 1 mA cm −2 (a). SEM images of Li obtained from the symmetrical Li cells after 20 cycles suggest that Li dendrites (b) were effectively suppressed in the electrolyte with 0.2% P123 (c).Image 1 Highlights: The polyether of Pluronic P123 has been developed as a bifunctional electrolyte additive. Introduction of 0.2% P123 into the electrolyte can greatly enhance the PE separator wettability. Addition of 0.2% P123 can effectively suppress Li dendrites on Li metal anode.