Highly Graphitized Porous Carbon‐FeNi 3 Fabricated from Oleic Acid for Advanced Lithium–Sulfur Batteries

Improving the electrical conductivity of sulfur, suppressing shuttle/dissolution of polysulfide, and enhancing reaction kinetics in Li–S batteries are essential for practical applications. Here, for the first time, we have used inexpensive oleic acid as a single carbon source, and have added commercial SiO 2 as a template to form a porous structure, whereas introducing Fe(NO 3 ) 3 and Ni(NO 3 ) 2 as catalysts to increase the degree of graphitization. Moreover, the dual metal salts Fe(NO 3 ) 3 and Ni(NO 3 ) 2 can also form FeNi 3 alloy, and our results show that FeNi 3 nanoparticles accelerate the kinetic conversion reactions of polysulfide. By virtue of the well‐developed porous structure and high degree of graphitization, the highly graphitized porous carbon‐FeNi 3 (GPC‐FeNi 3 ) has high conductivity to ensure fast charge transfer, and the hierarchically porous structure facilitates ion diffusion and traps polysulfide. Thus, a GPC‐FeNi 3 /S cathode displays excellent electrochemical performance. At current rates of 0.2 and 1 C, a cathode of the GPC‐FeNi 3 /S composite with a sulfur content of 70 % delivers high initial discharge capacities of 1108 and 880 mA h g −1 , respectively, and retains reversible specific capacities of 850 mA h g −1 after 200 cycles at 0.2 C and 625 mA h g −1 after 400 cycles at 1 C.