• • Symmetric cells with the Li3Bi/LiF interlayer sustain 2500 h of plating/stripping at 3 mA cm−2 and 3 mAh cm−2 with a voltage hysteresis of only 60 mV, indicating exceptional dendrite suppression and interfacial stability. This translates to a >5× extension in cycle life compared to conventional Li anodes, directly addressing the inferior cycling stability that has stalled LMB commercialization.
• • Full cells pairing BiF3-Li anodes with LiFePO4 cathodes retain 73% capacity after 1700 cycles at 1 C, demonstrating that the artificial interlayer mitigates capacity fade even under prolonged high-rate operation. This level of retention is critical for electric vehicle batteries, where >80% capacity after 1000 cycles is often required; the result suggests that further optimization could meet automotive targets.
• • The spontaneous reduction reaction between Li and BiF3 forms a Li3Bi/LiF composite in situ, eliminating the need for complex processing steps. The lithiophilic Li3Bi reduces the nucleation barrier, while LiF provides high ionic conductivity, enabling uniform Li+ flux. This dual-functionality directly addresses the two primary failure modes: dendrite growth and sluggish kinetics.
• • The interlayer effectively suppresses volume expansion and dead Li formation, as evidenced by the stable cycling performance. The 60 mV hysteresis at 3 mA cm−2 is among the lowest reported for Li metal anodes, indicating low interfacial resistance and efficient charge transfer. This performance metric is crucial for fast-charging applications, where high currents exacerbate dendrite growth.