Specific Adsorption Reinforced Interface Enabling Stable Lithium Metal Electrode

Lithium-metal (Li) electrode has been regarded as an excellent option to increase the energy density of next-generation secondary batteries due to its low electrochemical potential and ultrahigh theoretical capacity. However, Li electrodes suffer from poor Coulombic efficiency (CE) and uneven lithium deposition issues during cycling that severely restrain its application. Herein, ammonium perfluoro(2-methyl-3-oxahexanoate) (APFA), a pragmatic anionic surfactant, is introduced as an electrolyte additive to regulate the deposition behavior of lithium. Different from the conventional sacrificial additives that reinforce solid electrolyte interphase (SEI) layers on Li electrodes, the PFA(-) anions are mainly adsorbed on the Li surface, which improves the electron transfer step kinetics due to the psi 1 effect. The introduction of APFA in the electrolyte promises homogeneous and highly dense lithium deposition and the Li-Li symmetric cell with APFA can operate over 4000 h with excellent stability and low polarization. This work provides a facile and promising strategy for fabricating stable Li anode for high-energy-density secondary batteries.

Automated summary

This study introduces APFA as an electrolyte additive to regulate the deposition behavior of lithium, addressing the poor Coulombic efficiency and uneven lithium deposition issues of Li electrodes during cycling. The use of electrolyte with APFA enables the fabrication of stable high-energy-density secondary Li anode.