Electrospun Li-confinable hollow carbon fibers for highly stable Li-metal batteries

Abstract

Li-metal has steadily gained attention as one of the promising next-generation anode materials because of its exceptional specific capacity and low operating potential that can significantly increase the energy density of batteries beyond those of the state-of-the-art Li-ion batteries. Nevertheless, the use of Li-metal is still faced with the challenge of uncontrollable dendrite growth that ceaselessly causes parasitic reactions, further impeding the practical use of Li-metal batteries. To circumvent this limitation by using a structural approach, herein, we report a 1D hollow carbon fiber incorporating lithiophilic Au nanoparticles (Au@HCF) as a promising Li host that is fabricated by scalable dual-nozzle electrospinning. Due to its well-defined 1D electronic conducting pathways for reducing the effective current density as well as the hollow core for confining Li-metal, Au@HCF can mitigate Li dendrite growth on the top surface and stabilize the solid-electrolyte interphase layer, thereby achieving a high Coulombic efficiency of 99-99.9% under 1 mA cm-2 and 2 mAh cm-2. Moreover, the LiFePO4 full cell combined with the Au@HCF anode containing predeposited 2 mAh cm-2 Li showed considerably improved cycle life of over 380 cycles, indicating that the design concept for the Li-confinable structure can be an excellent option for realizing emerging Li-metal batteries.