Stable Li Metal Anode by a Hybrid Lithium Polysulfidophosphate/Polymer Cross-Linking Film

The practical application of rechargeable lithium (Li) metal batteries has long been hindered by the unstable Li metal anode with problems like Li dendrite growth, low Coulombic efficiency (CE), and short cycle life. Here, we demonstrate a multifunctional sulfur-containing hybrid Li polysulfidophosphate and poly(2-chloroethyl acrylate) cross-linking film that can provide effective protection for Li metal anode. This film can facilitate Li metal anode generating a stable organic/inorganic hybrid solid electrolyte interphase (SEI) layer containing multiple components such as polymer-tethered organo(poly)sulfide, inorganic Li polysulfidophosphate, Li sulfides, and Li salts. Thanks to this hybrid robust SEI layer, dendrite-free Li deposition and stable cycling of Li metal anode can be achieved (e.g., CE > 98.7% over 950 cycles). We demonstrated this Li protection technique enables both the protected Li metal anode and Li-metal-free anode cycling with significantly improved CEs and stability in full cells using LiFePO4 (∼2.4 mAh/cm2) cathode.