High Polarity Poly(vinylidene difluoride) Thin Coating for Dendrite-Free and High-Performance Lithium Metal Anodes

The high-polarity -phase poly(vinylidene difluoride) (-PVDF), which has all trans conformation with F and H atoms located on the opposite sides of the polymer backbone, is demonstrated to be a promising artificial solid-electrolyte interphase coating on both Cu and Li metal anodes for dendrite-free Li deposition/stripping and enhanced cycling performance. A thin (approximate to 4 mu m) -PVDF coating on Cu enables uniform Li deposition/stripping at high current densities up to 5 mA cm(-2), Li-plating capacity loadings of up to 4 mAh cm(-2), and excellent cycling stability over hundreds of cycles under practical conditions (1 mA cm(-2) with 2 mAh cm(-2)). Full cells containing an LiFePO4 cathode and an anode of either -PVDF coated Cu or Li also exhibit excellent cycling stability. The profound effects of the high-polarity PVDF coating on dendrite suppression are attributed to the electronegative F-rich interface that favors layer-by-layer Li deposition. This study offers a new strategy for the development of dendrite-free metal anode technology.