Simultaneously Inhibiting Lithium Dendrites Growth and Polysulfides Shuttle by a Flexible MOF-Based Membrane in Li-S Batteries

摘要

Lithium-sulfur (Li-S) batteries are considered a promising candidate for next-generation energy storage devices due to their ultrahigh theoretical energy density (approximate to 2600 Wh kg(-1)). However, the uncontrolled growth of Li dendrites and the adverse effect of polysulfide shuttling seriously hinder their practical applications. Herein, a metal organic framework based membrane (MOF@ PVDF-HFP) with good flexibility is designed and fabricated by a facial vacuum filtration strategy. The highly uniform pore sizes of MOF particles facilitate homogenous Li-ion fluxes, fundamentally inhibiting the growth of Li dendrites and resulting in stable Li plating/striping even at a quite high current density (10 mA cm(-2)). In addition, owing to the narrow pore size window of MOF nanoparticles, the MOF@ PVDF-HFP membrane serves as an effective barrier for suppressing the polysulfide shuttle, realizing an ultralong cycle life Li-S coin cell with an ultralow capacity fading upon 2000 cycles (0.015% per cycle). Moreover, high specific capacity (1269 mA h g(-1)) and excellent capacity retention (936 mA h g(-1) after 200 cycles) of a flexible Li-S pouch cell with a high sulfur loading (5.8 mg cm(-2)) demonstrate the potential of MOF@ PVDF-HFP membranes for the development of practical energy storage devices.