Carbon nanofibers implanted porous catalytic metal oxide design as efficient bifunctional electrode host material for lithium-sulfur battery

Abstract

The shuttling effect of lithium polysulfides (LiPSs) and uncontrolled dendrite formation of metal lithium anode are the two critical obstacles hindering the commercial application of lithium-sulfur (Li-S) batteries. Herein, a bifunctional electrode host design consists of carbon nanofibers implanted ordered porous Co-decorated Al2O3 supported on carbon nanotube film (CNTF) is proposed to address these problems. As cathode sulfur host material, benefiting from the synergistic effect of porous Co-Al2O3 and the embedded CNFs, the CNFs/Co-Al2O3@CNTF exhibits excellent conductivity, efficient LiPSs confinement and catalytic conversion performance. It shows a high initial capacity of 1165 mAh g−1 at 0.2 C, and holds a capacity of 594 mAh g−1 even up to 3 C. When serves as anode, the CNFs/Co-Al2O3@CNTF electrode exhibits excellent Li+ diffusion performance and uniform lithium growth behavior, achieving a dendrite-free lithium electrode. The anode also shows good cycle stability during an ultra-long cycle time of 1000 h. A flexible pack cell assembled from CNFs/Co-Al2O3@CNTF electrodes delivers a specific capacity of 972 mAh g−1 with capacity retention rate of 86.4% at 0.1 C.