Li₂CO₃/LiF‐Rich Heterostructured Solid Electrolyte Interphase with Superior Lithiophilic and Li⁺‐Transferred Characteristics via Adjusting Electrolyte Additives

Abstract

Abstract The structure and components of solid electrolyte interphase (SEI) is crucial to direct the growth of lithium particles. However, it is hard to have control over them. Herein, an SEI that shares the properties of Li 2 CO 3 ‐rich and LiF‐rich types is realized by using different fluorine phenylphospines, and constructing a Li 2 CO 3 /LiF‐rich heterostructured SEI by using tris(4‐fluorophenyl)phosphine (TFPP) as the electrolyte additive. The well‐balanced SEI formed in TFPP‐containing electrolyte has the fast Li + transport kinetics of Li 2 CO 3 , good electron insulator capability of LiF, and strong affinity toward Li + . It can effectively guarantee fast, uniform Li + flux through the SEI while preventing electrons from the Li anode entering into SEI, and thus realizes uniform and dense Li deposition at the SEI/Li interface. As expected, the Li anode with TFPP‐containing electrolyte achieves a stable Li plating/stripping over 400 h at 1mA cm −2 while the full cell with a high‐voltage LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode also enables long‐term stability with a capacity retention (87.8% after 200 cycles) at 0.1 A g −1 and excellent rate performance.