Preparation of Nitrogen and Fluorine Co-Doped Porous Carbon Aerogel and Its Application for Lithium-Sulfur Batteries
Lithium-sulfur batteries are recognized as a promising new generation of electrochemical energy storage technology due to their ultrahigh theoretical energy density.Despite these advantages,some major technical issues have to be solved for practical applications,such as low electrical conductivity,volume expansion,and the shuttle effect of polysulfides of sulfur electrodes.In this work,a Schiff base silica gel was synthesized through the aldehyde amine condensation of formaldehyde and 3-aminopropyltriethoxysilane,followed by a sol-gel transformation.By employing a freeze-drying process with polytetrafluoroethylene emulsion and subsequent thermal treatment,a porous nitrogen and fluorine co-doped carbon aerogel(NF-CA)was fabricated through a simultaneous etching of silica and carbonation mechanism.After loading sulfur as active material,the NF-CA/S cathode demonstrated superior electrochemical performance.Specifically,it manifested an impressive initial discharge capacity of up to 1 322 mA∙h/g at 0.2 C rate,retained a reversible capacity of 564 mA∙h/g after 200 cycles at 1 C rate,and exhibited a notable reversible capacity of 598 mA∙h/g under 2 C rate.
lithium-sulfur batteriesnitrogen and fluorine co-dopedcarbon aerogelNF-CA/Scathode material
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