Structure Regulation of Electric Double Layer via Hydrogen Bonding Effect to Realize High-Stability Lithium-Metal Batteries

The interfacial chemistry of solid electrolyte interphases (SEI) on lithium (Li) electrode is directly determined by the structural chemistry of the electric double layer (EDL) at the interface. Herein, a strategy for regulating the structural chemistry of EDL via the introduction of intermolecular hydrogen bonds has been proposed (p-hydroxybenzoic acid (pHA) is selected as proof-of-concept). According to the molecular dynamics (MD) simulation and density functional theory (DFT) calculation results, the existence of hydrogen bonds realizes the anion structural rearrangement in the EDL, reduces the lowest unoccupied molecular orbital (LUMO) energy level of anions in the EDL, and the number of free solvent molecules, which promotes the formation of inorganic species-enriched SEI and eventually achieves the dendrite-free Li deposition. Based on this strategy, Li||Cu cells can stably run over 185 cycles with an accumulated active Li loss of only 2.27 mAh cm(-2), and the long-term cycle stability of Li||Li cells is increased to 1200 h. In addition, the full cell pairing with the commercial LiFePO4 (LFP) cathodes exhibits stable cycling performance at 1C, with a capacity retention close to 90% after 200 cycles.