In situ construction of PVA/LiF composite artificial protective layer to assist dendrite-free Li metal anode

Lithium (Li), with superior specific capacity and lowest standards electrode potential, has been touted as the “Holy Grail” among various anode materials. However, in the process of repeated lithium plating/stripping, the uncontrollable lithium dendrite growth and unstable interface inevitably affect the application of lithium metal batteries. Here, an ingeniously designed artificial protective layer consisting of polyvinyl alcohol polymer and lithium fluoride was coated on a Cu current collector to overcome the obstacles above. High Young’s modulus and favourable ionic conductivity are ensured through the synergistic interaction between soft and rigid structural elements evenly distributed in the layer. Dense Li deposition with no dendrite, conspicuously reduced interfacial resistance, and dramatically prolonged cycle life were achieved, ascribing to the interface stabilization by the artificial protective layer. This work shed light on the artificial protective layer design strategy and the energetic chemistry and mechanics of anodes in working batteries.