A porous rGO with high specific surface area and high content of doped-N modifying the separator for high performance Li-S battery

Abstract

HSN-rGO with high specific surface area and high content of N is prepared via GO reduction and N-doping of DMF, corrosion oxidation pore-forming of H2O2 as well as further reduction and N-doping of N2H4•H2O under the solvothermal condition. The porous HSN-rGO has a high BET specific surface area of 464.3 m2 g−1. The N content in HSN-rGO is 5.27 at.%. The HSN-rGO shows a strong adsorption capability for the soluble lithium polysulfides (LiPSs) and more importantly it presents an excellent catalytic capability for the redox conversion of LiPSs. The HSN-rGO modified separator can inhibit the shuttle effect of LiPSs in Li-S battery. Besides, the HSN-rGO based separator has a good electrolyte wettability. The catalytic activity of HSN-rGO and Li+ diffusion property in Li-S battery are well studied quantitatively. The Li-S battery with HSN-rGO-PP separator exhibits a high initial discharge capacity of 1372.8 mAh g−1 at 0.1 C and 681.5 mAh g−1 at 2 C, and a low-capacity decay rate of 0.055% per cycle for 1000 cycles at 1 C. This study proves the strategy that the HSN-rGO modified separator can effectively inhibit the shuttle effect of LiPSs and accelerate the redox reaction kinetics for high-performance Li-S battery.