Flexible Quasi-Solid-State Composite Electrolyte Membrane Derived from a Metal-Organic Framework for Lithium-Metal Batteries

In this work, we developed a new kind of flexible Li-ion conductor membrane consisting of poly(vinylidene fluoride-co-hexafluoropropylene) matrix and ionic liquid absorbed in metal-organic framework (MOF) particles. This composite membrane facilitates a homogeneous Li-ion flux and exhibits an excellent ionic conductivity of about 4.3x10(-4)Scm(-1) at room temperature, a wide electrochemical window of 4.8V (vs. Li+/Li), as well as good thermal stability and flexibility. The quasi-solid-state lithium metal battery assembled with the composite electrolyte membrane, a Li metal anode, and a composite cathode shows low interface impedance and a reversible discharge capacity of 149mAhg(-1) within 300 cycles at 0.1C. This new kind of quasi-solid-state electrolyte membrane is a promising candidate for solid-state lithium-metal batteries with a high energy density.