Constructing LiF/Li₂CO₃-rich heterostructured electrode electrolyte interphases by electrolyte additive for 4.5 V...

The cycling performance of promising high-voltage Li||LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) batteries is determined by the interfacial stability between electrodes and electrolyte. However, it is challenging to achieve them under high voltage. Herein, we stabilized 4.5 V Li||NCM811 batteries via electrolyte engineering with pentafluorostyrene (PFBE) as the additive. PFBE contributes to the formation of highly Li⁺ conductive and mechanically robust LiF/Li₂CO₃-rich heterostructured interphases on NCM811 cathode and Li metal anode (LMA) surfaces. Such electrode-electrolyte interphases (EEIs) obviously alleviate irreversible phase transition, microcracks induced by stress accumulation and transition metal dissolution in the Ni-rich layered cathode. Meanwhile, the growth of Li dendrites on the LMA surface is effectively controlled. As expected, 4.5 V Li||NCM811 batteries sustain a capacity retention rate of 61.27% after 600 cycles at 0.5 C (100 mA g^-1). More importantly, ∼6.69 Ah Li||NCM811 pouch cells with such electrolytes could represent a stable energy density of ∼485 Wh kg^-1 based on all cell components.