Synergistic Effect of Dual-Anion Additives Promotes the Fast Dynamics and High-Voltage Performance of Ni-Rich Lithium-Ion Batteries by Regulating the Electrode/Electrolyte Interface.

Combining the Ni-rich layered cathode (Ni ≥ 80%) with high operating voltage is considered as a feasible solution to achieve high-energy lithium-ion batteries (LIBs). However, the working voltage is limited in practical applications due to the poor interface stability in traditional carbonate electrolytes. Herein, LiBF 4 and LiNO 3 are added as film-forming additives and 1.0 M LiPF 6 in SL/FEC/EMC with 0.5 wt % LiBF 4 -LiNO 3 (HVE) is obtained. A uniform and inorganic-rich cathode electrolyte interphase (CEI) as well as a dense and Li 3 N-LiF-rich solid electrolyte interphase (SEI) could be in situ generated on LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) and graphite (Gr) electrode in HVE, respectively. The robust interface film with electronic insulation and ionic conductivity effectively stabilizes the NCM811/Gr-electrolyte interfaces and improves the Li + diffusion kinetics, enabling the high-load NCM811-Gr to maintain 85.2% capacity (∼180 mA h g -1 ) after 300 cycles under 4.4 V. Besides, the 4.2 V NCM811-Gr retains 90.4% of the initial capacity after 200 cycles at 2 C (∼6 mA h cm -2 ). Compared with the traditional carbonate electrolyte (LB301), HVE has obvious advantages in terms of high-voltage and fast dynamics performance. Especially, good thermal stability and economy make HVE a promising electrolyte for commercial high-energy LIBs.