An Interconnected Channel-Like Framework as Host for Lithium Metal Composite Anodes

摘要

Lithium (Li) metal anodes have long been counted on to meet the increasing demand for high energy, high-power rechargeable battery systems but they have been plagued by uncontrollable plating, unstable solid electrolyte interphase (SEI) formation, and the resulting low Coulombic efficiency. These problems are even aggravated under commercial levels of current density and areal capacity testing conditions. In this work, the channel-like structure of a carbonized eggplant (EP) as a stable "host" for Li metal melt infusion, is utilized. With further interphase modification of lithium fluoride (LiF), the as-formed EP-LiF composite anode maintains approximate to 90% Li metal theoretical capacity and can successfully suppress dendrite growth and volume fluctuation during cycling. EP-LiF offers much improved symmetric cell and full-cell cycling performance with lower and more stable overpotential under various areal capacity and elevated rate capability. Furthermore, carbonized EP serves as a light-weight high-performance current collector, achieving an average Coulombic efficiency approximate to 99.1% in ether-based electrolytes with 2.2 mAh cm(-2) cycling areal capacity. The natural structure of carbonized EP will inspire further artificial designs of electrode frameworks for both Li anode and sulfur cathodes, enabling promising candidates for next-generation high-energy density batteries.