LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathodes paired with graphite anode emerge as promising alternatives for the current power batteries. Unfortunately, the structural degradation of Ni-rich cathodes at high working voltage brings about serious capacity fading, sequentially hampering their practical use in lithium-ion batteries (LIBs). In this work, phenyl 4-fluorobenzene sulfonate (PFBS) is investigated as a multifunctional film-forming additive to suppress the structural degradation of NCM811 and alleviate the chemical decomposition of electrolyte solvents. Computational and experimental results prove that the PFBS molecule preferentially occurs in electrochemical reactions than the electrolyte solvents on both cathode and anode to form stabilized and uniform solid electrolyte interphase (SEI). The presence of 1.0 wt% PFBS is conducive to maintaining a stable SEI at NCM811 cathode, thus mitigating the irreversible structural transformation and holding the stability of the SEI on the graphite surface. Due to the multifunctional feature of PFBS, the electrochemical performances of NCM811//graphite pouch cell significantly improved at -20 °C, 25°C, and 45°C. Notably, the pouch cell with a PFBS additive achieves capacity retention of 89.9% over 400 cycles at 1C under 25℃, which is much superior to that of 29.3% for the PFBS free one. Furthermore, the pouch cell with 1wt% PFBS in electrolyte also achieved superior capacity retention at 45℃ (89.01%) and -20 °C (49.18%) at 1C. Theoretical calculation and XPS analysis reveal that the -OSO₂- and -F functional groups of PFBS not only joined the formation of stable SEI but also facilitate the diffusion of Li ions. The excellent cycling performance achieved at a wide-temperature region with PFBS demonstrates that this functional molecule is a prospect for applications in power LIBs.

DOI：10.1021/acsaem.2c00682