P, O, and N heteroatom-doped hollow carbon on graphene (PONHC/G) from nanosized LiFePO4 (LFP) as a hard template is shown to be a very efficient sulfur host for lithium-sulfur (Li-S) batteries. The PONHC/G made from LFP nanoparticles as hard materials provides sufficient voids with various pore sizes for sulfur storage, and doping of the carbon structures with various heteroatoms minimized dissolution/diffusion of the polysulfides. The obtained PONHC/G can store sulfur and mitigate diffusion of the dissolved polysulfide owing to the well-organized host structure and the strong chemical affinity for polysulfides because of the polarization effect of the heteroatom dopants. As a cathode, S@PONHC/G shows excellent cycle stability and rate capability, as confirmed by polysulfide adsorption analysis. Therefore, PONHC/G may show high potential as a sulfur scaffold in the commercialization of Li-S batteries through additional modification and optimization of these host materials.
Keywords: LiFePO4; cathodes; graphene; heteroatoms; lithium−sulfur batteries.