A self-supported carbon nanofiber paper/sulfur anode with high-capacity and high-power for application in Li-ion batteries

A self-supported carbon nanofiber paper (CNFP)/sulfur composite is investigated as the anode of Li-ion batteries instead of the cathode of lithium-sulfur batteries. Relative to the total mass of all the electrode components, the CNFP/sulfur anode exhibits a reversible capacity of ∼310 mAh g−1. Moreover, the CNFP/sulfur anode maintains 95% of capacity after 1000 cycles and exhibits considerably better high-power capability than the graphite anode. Different from the conventional lithium-sulfur batteries that are based on the conversion reaction of sulfur to Li2S in the potential range of 3.0-1.5 V vs. Li/Li+, it is assumed that the reversible Li-ion storage ability of sulfur below 1.5 V vs. Li/Li+ in the CNFP matrix can be attributed to the rapid adsorption/desorption of Li-ions on the surface of sulfur. The average working voltage of 3.0 V for a full cell consisting of CNFP/sulfur anode and LiFePO4 cathode demonstrates the successful application of carbon/sulfur anode in Li-ion batteries.