Soft, robust, Li-ion friendly halloysite-based hybrid protective layer for dendrite-free Li metal anode

Abstract

Li metal, which has a super high specific capacity and the lowest redox potential, is an attractive anode material for electric vehicle batteries. However, the application of Li metal in commercial batteries is hindered by safety issues associated with dendrite accumulation on the anode surface owing to a nonuniform Li-ion distribution during the discharge process. Herein, a halloysite-poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hybrid is developed as a synergistic soft and robust protective layer for Li metal to realize excellent interfacial stability during long-term cycling. The halloysite-PVDF-HFP hybrid layer suppresses nonuniform Li deposition and side reactions between Li metal and the organic electrolyte, resulting in a dendrite-free Li-metal anode. In addition, synergy between soft PVDF-HFP and robust halloysite uniformly dispersed in the hybrid layer amplifies the dielectric constant, thus improving Li-ion conductivity. The excellent physical properties of the hybrid layer also provide compatibility with Li metal and high electrochemical stability. This work highlights an economical and easily accessible new strategy for developing synergistic organic/inorganic materials to stabilize Li-metal anodes and obtain insights into the energy chemistry of anodes in battery systems.