High-Power Li-Metal Anode Enabled by Metal-Organic Framework Modified Electrolyte

Although the Li-metal anode holds the key to overcoming the bottleneck of current Li-ion rechargeable batteries, the trade-off between safety and practicality, especially at high current densities, is a major barrier because of the formation of hazardous Li dendrites arising from inhomogeneous Li electrodeposition. Herein we demonstrate the feasibility of achieving homogeneous Li electrodeposition by implementing porous metal-organic framework (MOF) species in pristine liquid electrolyte. The MOF host provides considerable natural angstrom-level pores that preferentially control the migration of large-sized anions. Consequently, the “caged” electrolyte anions facilitate a homogeneous Li-ion flux, which illustrates a stable Li-metal plating/stripping at a practically high current density (10 mA cm−2). As a proof of concept, the high areal-loading Li-Li4Ti5O12 batteries (∼10 mg cm−2) with the MOF-modified electrolyte deliver excellent long-life cycling at high current densities (∼7 mA cm−2). Our results underline the great potential of MOFs in tuning the electrolyte properties to achieve desirable Li-metal battery performance.