High potential activated multifunctional additive inducing favorable electrode-electrolyte interface for nickel-rich batteries cycling at 4.7 V

Lithium metal batteries paired with high-voltage nickel-rich cathodes offer high energy density. However, stable operation at ultra-high voltages (>4.5 V) requires suppression of severe interfacial degradation. Herein, difluoropyridine-boronic acid (DFPBA) is proposed as a multifunctional electrolyte additive to construct synergistic electrode/electrolyte interphases (EEIs). DFPBA preferentially decomposes to form a dense hybrid cathode electrolyte interface (CEI) comprising LiF, Li 3 N and LiB x O y . Simultaneously, DFPBA optimizes the solid electrolyte interphase (SEI) on lithium metal anodes, enhancing structural integrity. The lone-pair electrons of nitrogen (N) atoms in DFPBA suppress HF formation, while boric acid derivatives reinforce EEI mechanical stability. Consequently, the rapidly formed CEI at 4.7 V enables the Li||NCM622 cells to achieve 80.4% capacity retention after 400 cycles, surpassing cells without DFPBA (45.5%). This study demonstrates the exceptional electrochemical performance achieved with NCM622 cathodes at high voltages, providing pivotal insights for developing advanced electrolytes targeting demanding energy storage systems. • The DFPBA preferentially undergoes redox and participates SEI/CEI film formation. • DFPBA enables rapid formation of a thin and dense CEI film at 4.7 V. • DFPBA delivers 80.4 % capacity retention in Li.||NCM622 after 400 cycles at 4.7 V. • The mechanism of DFPBA is revealed based on decomposition pathway analysis.