Multifunctional Electrolyte Additive toward Moisture‐Tolerant, High Voltage (4.8 V) and Wide Temperature (−10 to 60 °C) Adaptable Lithium‐Ion Battery

Abstract Enhancing the tolerance of Li‐ion batteries (LIBs) to high charging voltage and extreme climates is pivotal for further widespread application. Nevertheless, practical capacity utilization is severely constrained by interfacial parasitic reactions, electrolyte consumption, and sluggish kinetics. Modulating the electrode/electrolyte interphase (EEIs) with functional additives is a favorable approach. Herein, a novel multifunctional electrolyte additive, diethyl [4‐(Trifluoromethyl) benzyl] phosphonate (DBP) containing fluorine, phosphate, and phenyl groups is proposed to simultaneously modify both cathode and anode of LIBs. The preferential decomposition of DBP facilitates the formation of a mechanically robust and ionically conductive EEIs. The DBP‐derived cathode‐electrolyte interphase (CEI) is capable of suppressing transition metal‐ion dissolution and cation disorder. Moreover, DBP exhibits multifunctional benefits, including accelerating Li + transport, scavenging free radicals, and curbing the hydrolysis of LiPF 6 . Therefore, with optimized DBP additive, Li||NCM622 cell achieves advanced performance under harsh conditions, e.g. high temperature (60 °C), low temperature (−10 °C), and high cut‐off voltage (4.6 and 4.8 V). Furthermore, the Li||Li symmetric cell cycles for over 450 h at 0.5 mA cm −2 /0.5 mAh cm −2 stably, which demonstrates the potential to be applied into practical LIBs.