Specific Adsorption Reinforced Interface Enabling Stable Lithium Metal Electrode

• Published in: Advanced functional materials 2022-05, Vol.32 (18), p.n/a
• Main Authors: Wang, Yu‐Yang, Gu, Jian‐Kang, Zhang, Bo‐Hai, Li, Guo‐Ran, Liu, Sheng, Gao, Xue‐Ping
• Format: Article
• Language: English
• Subjects: Additives; Deposition; electric double layer; Electrochemical potential; Electrode polarization; Electrodes; Electrolytes; Electron transfer; Flux density; interfaces; Lithium; lithium electrodes; Materials science; Solid electrolytes; specific adsorption; Storage batteries
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202112005

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 ψ1 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. An organic surfactant of ammonium perfluoro(2‐methyl‐3‐oxahexanoate) as an electrolyte additive is employed for lithium electrodes. Because of the adsorption of the additive anions and the adapted electrical double layer on the surface, the electrode kinetics is greatly promoted, thus enabling a stable lithium electrode.