Semi-Embedded Structured Bi Nanospheres for Boosted Self-Heating-Induced Healing of Li-Dendrites.

It is reported that self-heating-induced healing on lithium metal anodes (LMAs) provides a mitigation strategy for suppressing Li dendrites. However, how to boost the self-heating-induced healing of Li-dendrites and incorporate it into Li-host design remains an imminent problem that needs to be solved. Herein, a new bismuth nanosphere semi-buried carbon cloth (Bi-NS-CC) material with a 3D flexible host structure is proposed. The ultrasmall Bi nanospheres are uniformly and densely distributed on carbon fiber, providing active sites to form uniform Li3 Bi alloy with molten lithium, thereby guiding the injection of molten metallic lithium into the 3D structure to form a self-supporting composite LMAs. The ingenious semi-embedded structure with strong interfacial C─Bi ensures superior mechanical properties. Interestingly, when the current density reaches up to 10 mA cm-2 , the lithium dendrites undergo self-heating. Carbon cloth as a host can quickly and uniformly transfer heat, which induces the uniform migration of Li on anodes. The semi-embedded structure with strong C─Bi ensures Bi nanospheres guide the formation of smooth morphology even under these harsh conditions (high-temperature, high-rate, etc.). Consequently, at 10 mA cm-2 /10 mAh cm-2 , the Li/Li3 Bi-NS-CC realizes ultra-long cycles of 1500 h and ultra-low overpotential of 15 mV in a symmetric cell.