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

Abstract

Abstract The high‐polarity β‐phase poly(vinylidene difluoride) (β‐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 (≈4 µm) β‐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 LiFePO 4 cathode and an anode of either β‐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.