S-doped porous carbon fibers with superior electrode behaviors in lithium ion batteries and fuel cells

The orientation construction of S-doped porous carbon fibers (SPCFs) is realized by the facile template-directed methodology using asphalt powder as carbon source. The unique fiber-like morphology without destruction can be well duplicated from the template by the developed methodology. MgSO₄ fibers serve as both templates and S dopant, realizing the in-situ S doping into carbon frameworks. The effects of different reaction temperatures on the yield and S doping level of SPCFs are investigated. The S doping can not only significantly enhance the electrical conductivity, but also introduce more defects or disorders. As anode material for lithium ion batteries (LIBs), SPCFs electrode delivers better rate capability than undoped PCFs. And the capacity of SPCFs electrode retains around 90% after 300 cycles at 2 A g⁻¹, exhibiting good cycling stability. As the electrocatalysts for fuel cells, the onset potentials of SPCFs obtained at 800 and 900 °C are concentrated at 0.863 V, and the higher kinetic current densities at 0.4 V of them are larger than that of PCFs, demonstrating the superior electrocatalytic performance. Due to the synergistic effect of abundant pore channels and S doping, SPCFs electrode exhibits superior electrochemical performances as anode for LIBs and elecctrocatalyst for fuel cells, respectively. Additionally, the oriented conversion of asphalt powder into high-performance electrode material in this work provides a new way for the high value application of asphalt.