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Promoting industry applications of high‐energy Li metal batteries (LMBs) is of vital importance for accelerating the electrification and decarbonization of our society. Unfortunately, the time‐dependent storage aging of Ah‐level Li metal pouch cells, a ubiquitous but crucial practical indicator, has not yet been revealed. Herein, we first report the storage behaviors and multilateral synergistic aging mechanism of Ah‐level NCM811||Li pouch cells during the 120‐day long‐term storage under various conditions. Contrary to the conventional belief of Li‐ion batteries with graphite intercalation anodes, the significant available capacity loss of 32.8% on average originates from the major electrolyte‐sensitive anode corrosion and partial superimposed cathode degradation, and the irreversible capacity loss of 13.3% is essentially attributed to the unrecoverable interface/structure deterioration of NCM with further hindrance of the aged Li. Moreover, principles of alleviating aging have been proposed. This work bridges academia and industry and enriches the fundamental epistemology of storage aging of LMBs, shedding light on realistic applications of high‐energy batteries. [ABSTRACT FROM AUTHOR]

Abstract Promoting industry applications of high‐energy Li metal batteries (LMBs) is of vital importance for accelerating the electrification and decarbonization of our society. Unfortunately, the time‐dependent storage aging of Ah‐level Li metal pouch cells, a ubiquitous but crucial practical indicator, has not yet been revealed. Herein, we first report the storage behaviors and multilateral synergistic aging mechanism of Ah‐level NCM811||Li pouch cells during the 120‐day long‐term storage under various conditions. Contrary to the conventional belief of Li‐ion batteries with graphite intercalation anodes, the significant available capacity loss of 32.8% on average originates from the major electrolyte‐sensitive anode corrosion and partial superimposed cathode degradation, and the irreversible capacity loss of 13.3% is essentially attributed to the unrecoverable interface/structure deterioration of NCM with further hindrance of the aged Li. Moreover, principles of alleviating aging have been proposed. This work bridges academia and industry and enriches the fundamental epistemology of storage aging of LMBs, shedding light on realistic applications of high‐energy batteries.

Tailored artificial solid electrolyte interphase (SEI) is favorable for the stabilization of Li metal batteries (LMBs) and Li anode dendrite suppression. Here, an open framework perovskite derivate SEI with fluorinated heterogeneous nanodomains is proposed. The nano-structural K 3 FeF 6 perovskite coating on Li anode can spontaneously convert into the robust SEI composed of KF, LiF and Fe nanodomains. The introduction of KF and Fe components could enhance the interface conductivity around LiF domains in SEI, beneficial for the homogenization of Li-ion flux and Li-mass plating. The residual K 3 FeF 6 component with 3D open channels (even after long-term cycling) can serve as isotropic porous modulator to reduce the local current density and mitigate the volume change of electrode. This perovskite modified Li anode enables a long cycling life of 1100 h under 2 mAh cm−2 capacity for Li||Li symmetric cells. The modified LMBs with LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode exhibit the ultralong 3300 cycles at 1 C. The corresponding pouch cells based on thick cathode (30 mg cm−2) enable a reversible capacity as high as 1.5 Ah, corresponding to an energy density of 236 Wh kg−1 based on the weight of whole packet under the protocols of N/P ratio of 1.28 and E/C ratio of 4.23 g Ah−1. [Display omitted] • An open framework perovskite derivate SEI with fluorinated heterogeneous nanodomains is proposed. • The nano-structural K 3 FeF 6 coating on Li anode can convert into the SEI composed of KF, LiF and Fe nanodomains. • The introduction of KF and Fe could enhance the interface conductivity around LiF domains in SEI. • The modified LMBs with LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode exhibit the ultralong 3300 cycles at 1 C. • The pouch cells based on thick cathode enable a 1.5 Ah capacity, corresponding to 236 Wh kg−1 based on the packet weight. [ABSTRACT FROM AUTHOR]