In-situ organic SEI layer for dendrite-free lithium metal anode

Abstract Lithium metal (Li) is the most promising anode for high energy density secondary battery system, but the dendrite growth makes it very dangerous for commercial application. An artificial SEI layer with high ionic conductivity and low electronic conductivity has proven to be an effective way to improve the stability of Li anode. Organic layer is introduced on Li surface by in-situ spontaneous reaction between Li and carboxylic acid. The as-formed carboxylate layer can effectively limit the Li deposition under it and suppress the dendrite growth. And the uniformity of the organic layer is the key factor for achieving stable cycling performance. With a homogenous carboxylate layer of 1 ​μm, the Li electrode can sustain 1000 ​h of charge-discharge cycling at 0.5 ​mA ​cm−2. DFT calculation demonstrates that the enhanced absorption energy by oxygen atoms in lithium carboxylate contributes to the increased lithiophilicity and decreased depositing overpotential. This research provides a way for practical application of Li metal anode.