In Situ Formed Lithiophilic LixNbyO in a Carbon Nanofiber Network for Dendrite-Free Li-Metal Anodes.

Lithium metal is considered as a strongly attractive anode candidate for the high-energy-storage field, but its dreadful dendrite growth has haunted its commercialization progress. Herein, we develop a lithiophilic Nb2O5-embedded three-dimensional (3D) carbon nanofiber network (Nb2O5-CNF) as a scaffold to preload molten Li for the fabrication of dendrite-free composite anode. The in situ lithiation reaction between molten Li and Nb2O5 nanocrystals results in the formation of nanosize LixNbyO nanoparticles, which can serve as preferred sites that regulate nucleation/growth behavior of Li during the plating process. Besides, due to its high structural stability and abundant internal inner space, the 3D CNF network can function as a reservoir to confine the dimensional expansion of "hostless Li". The resulting Li composite anodes exhibit enlarged active areas and reduced interfacial energy barriers, delivering a prolonged cycling of 1000 h with an ultralow hysteresis of 52 mV and dendrite-free morphology in a symmetric cell (1.0 mA cm-2). Coupled with the LiFePO4 cathode, the Li@Nb2O5-CNF anode sustains a reversible capacity of 163 mAh g-1 with an excellent capacity retention of 93.0% after 370 cycles at 0.5C. This all-around strategy of lithiophilic sites coupled with a 3D conductive nanofiber matrix may shed light on promising applications of high-capacity and dendrite-free Li-metal batteries.