Ni-rich (Ni≥0.8) LiNi x Co y Mn 1− x −y O 2 (NCM) cathode materials have attracted great interest for high-energy-density lithium ion batteries (LIBs). However, layered oxides of Ni-rich CAMs are suffering from the notorious structural and interfacial degradation in the liquid electrolyte , especially at high state-of-charge (voltage) and temperature, which leads to electrochemical performance deterioration and thermal runaway of the cell. This work systematically and comprehensively reveals the underlying mechanism of the electrolyte additive phenyl trifluoromethyl sulfide (PTS) to enhance the electrochemical property of Ni-rich layered oxides at high voltage (∼4.6 V) and high-temperature (∼50 °C). Specifically, PTS observably encourages the electrode stability via cathode-electrolyte interface strengthening and reactive oxygen species deactivating mechanism, which facilitates the NCM811 cathode to adapt to the deep charging state as well as the highly oxidized environment. The binding energy calculation results reveal that the superoxide radical could steadily adsorb on the S radical or Li + sites by interacting with Li + , thus making the superoxide radical deactivated. With the interface strengthening of PTS, the Ah-level NCM811||Gr pouch cell exhibits excellent cycling stability. This work affords a guide to designing electrolytes for Ni-rich LIBs towards high-voltage and high-temperature.
Pairing high-energy nickel-rich cathodes with current collectors as anodes presents a compelling strategy to significantly boost the specific energy of rechargeable lithium-ion batteries, driving progress toward a transportation revolution. However, the limited active lithium inventory sourced by the cathodes tend to be rapidly consumed by irreversible Li plating/stripping and interfacial side reactions. To address these limitations, we propose a dual-gradient metal layer as an innovative solution to mitigate active Li loss by promoting uniform Li deposition and in situ formation of a stable solid electrolyte interphase. The operation of these batteries is investigated using a combination of electrochemical and chemical techniques to differentiate dead Li and interphase-bound Li inventory loss as well as material characterization methods to analyse the plated Li and interfacial composition and morphology. The developed dual gradient metal layer-based 600 mAh LiNi 0.9 Co 0.05 Mn 0.05 O 2 | |Cu pouch cells achieve an areal capacity of 7.25 mAh cm −2 and deliver an 80% capacity retention over 160 cycles. We show that the proposed approach is compatible with a range of different metal materials, offering a promising path toward next generation long-lasting, high-energy, initially active material-free anode based Li metal batteries.
危险品化学品经营许可证（带存储）