Sandwich‐Model Cathode Electrolyte Interphase Facilitating All‐Climate High‐Voltage Nickel‐Rich Cathode‐Based Lithium Metal Batteries with LiBF ₄ ‐Based Electrolyte

Abstract

Abstract All‐climate lithium metal batteries are highly needed, but remains a huge challenge in cycling life due to the existence of unstable electrode electrolyte interphases, especially with nickel‐rich layered oxide cathode at high cut‐off voltage. To address this question, a functional and robust sandwich‐model cathode electrolyte interphase (CEI) is proposed, derived from a LiBF 4 ‐based electrolyte modified with para‐fluorobenzeneacetonitrile (P‐FBCN) additive, to realize the stability of 4.8 V Li||LiNi 0.94 Co 0.05 Mn 0.01 O 2 (NCM94) battery operated from −60 to 60 °C. The LiF‐rich sandwich‐model CEI features an outer layer of LiB x O y ‐rich to enhance mechanical/thermal stability, and the inner −C≡N‐rich anchoring layer to facilitate Li⁺ conduction and inhibit the dissolution of transition metal ions. Notably, the 7.6 Ah‐grade Li||NCM94 pouch cell with such electrolyte can yield a high energy density of 544 Wh kg −1 with a long lifespan of 158 cycles.