Highly-rough surface carbon nanofibers film as an effective interlayer for lithium–sulfur batteries

Lithium–sulfur(Li–S)battery with a new configuration is demonstrated by inserting a flexible nitrogen-doping carbon nanofiber(N-CNFs)interlayer between the sulfur cathode and the separator.The N-CNFs film with high surface roughness and surface area is fabricated by electrospinning and a subsequent calcination process.The N-CNFs film interlayer not only effectively traps the shuttling migration of polysulfides but also gives the whole battery reliable electronic conductivity,which can effectively enhance the electrochemical performance of Li–S batteries.Finally,Li–S batteries with long cycling stability of 785 mAh/g after 200 cycles and good rate capability of 573 mAh/g at 5 C are achieved.

Fabricating titanium dioxide/N-doped carbon nanofibers as advanced interlayer for improving cycling reversibility of lithium-sulfur batteries

"Shuttle effect" is detrimental for maintaining the high capacity and cycling reversibility of lithium-sulfur batteries(LSBs).To inhibit polysulfide migration,N-doped carbon nanofibers(N-CNFs) membrane comprising TiO_(2)nanoparticles(TiO_(2)/N-CNFs) is fabricated using an electrospinning-calcination method and further applied as interlayer in LSBs.The TiO_(2)/N-CNFs interlayer helps the battery to deliver a high specific capacity of 1155.2 mA·h·g^(-1)at 0.2 C with high Coulombic efficiency,good rate capability and stability.When cycling at 0.5 C,a capacity retention rate of 62.4% is achieved over 300 cycles,which is higher than that of CNFs and TiO_(2)/CNFs counterparts.The excellent performance should mainly be attributed to the alleviated "shuttle effect" deriving from high polysulfide trapping ability of TiO_(2)nanoparticles and N heteroatoms in interwoven CNFs.