TiO 2 -decorated porous carbon nanofiber interlayer for Li-S batteries.

Lithium-sulfur (Li-S) batteries are the most promising energy storage systems owing to their high energy density. However, shuttling of polysulfides detracts the electrochemical performance of Li-S batteries and thus prevents the commercialization of Li-S batteries. Here, TiO 2 @porous carbon nanofibers (TiO 2 @PCNFs) are fabricated via combining electrospinning and electrospraying techniques and the resultant TiO 2 @PCNFs are evaluated for use as an interlayer in Li-S batteries. TiO 2 nanoparticles on PCNFs are observed from SEM and TEM images. A high initial discharge capacity of 1510 mA h g -1 is achieved owing to the novel approach of electrospinning the carbon precursor and electrospraying TiO 2 nanoparticles simultaneously. In this approach TiO 2 nanoparticles capture polysulfides with strong interaction and the PCNFs with high conductivity recycle and re-use the adsorbed polysulfides, thus leading to high reversible capacity and stable cycling performance. A high reversible capacity of 967 mA h g -1 is reached after 200 cycles at 0.2C. The cell with the TiO 2 @PCNF interlayer also delivers a reversible capacity of around 1100 mA h g -1 at 1C, while the cell without the interlayer exhibits a lower capacity of 400 mA h g -1 . Therefore, this work presents a novel approach for designing interlayer materials with exceptional electrochemical performance for high performance Li-S batteries.