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In this work, we successfully synthesized porous C/Fe3O4 microspheres by spray pyrolysis at 700ºC with a sodium nitrate (NaNO3) additive in the precursor solution. Furthermore, we studied their electrochemical properties as anode material for Li-ion batteries. The systematic studies by various characterization techniques show that NaNO3 catalyzes the carbonization of sucrose and enhances the crystallization of Fe3O4. Moreover, an aqueous etching can easily remove sodium compounds to produce porous C/Fe3O4 microspheres with large surface areas and pore volumes. The porous C/Fe3O4 microspheres exhibit a reversible capacity of ~780 mAh g–1 in the initial cycles and ~520 mAh g–1 after 30 cycles at a current density of 50 mA g–1. Moreover, a reversible capacity of ~400 mAh g–1 is attainable after 200 cycles, even at a high current density of 500 mA g–1. The wide range of pores produced from the removal of sodium compounds might enable easy electrolyte penetration and facilitate fast Li-ion diffusion, while the N-doping can promote the electronic conductivity of the carbon. These features of porous C/Fe3O4 microspheres led to the improved electrochemical properties of this sample. [ABSTRACT FROM AUTHOR]

The free‐standing cobalt phosphides‐based composite nanofiber mats with different compositions (CoyP/C, CoxP/Co3(PO4)2/C, where 2>x>y>1) were synthesized by electrospinning with heat treatments and applied as multi‐functional interlayers for lithium‐sulfur batteries. The polysulfide confining ability of the interlayers was evaluated by a static polysulfide adsorption test and an electrochemical conversion test using symmetric cells. The CoxP/Co3(PO4)2/C exhibited better catalytic performance for converting polysulfides, owing to the combination of CoxP with Co3(PO4)2 and P‐doped carbon. As a result, the lithium‐sulfur cell with this interlayer delivered a high initial discharge capacity of 1483 mAh g−1 at 0.1 C, retaining 705 mAh g−1 after 200 cycles at 0.5 C with 100 % Coulombic efficiency. The polysulfide trapping by the interlayer was further elucidated from the results of its ex situ characterizations after discharge and charge processes at different cycles in lithium‐sulfur cells. [ABSTRACT FROM AUTHOR]