Poly ionic liquid Nanovesicle Templated Carbon Nanocapsules Functionalized with Uniform Iron Nitride Nanoparticles as Catalytic Sulfur Host for Li S Batteries
Poly ionic liquid s PIL are common precursors for heteroatom doped carbon materials. Despite a relatively higher carbonization yield, the PIL to carbon conversion process faces challenges in preserving morphological and structural motifs on the nanoscale. Assisted by a thin polydopamine coating route and ion exchange, imidazolium based PIL nanovesicles were successfully applied in morphology maintaining carbonization to prepare carbon composite nanocapsules. Extending this strategy further to their composites, we demonstrate the synthesis of carbon composite nanocapsules functionalized with iron nitride nanoparticles of an ultrafine, uniform size of 3 5 nm termed FexN C . Due to its unique nanostructure, the sulfur loaded FexN C electrode was tested to efficiently mitigate the notorious shuttle effect of lithium polysulfides LiPSs in Li S batteries. The cavity of the carbon nanocapsules was spotted to better the loading content of sulfur. The well dispersed iron nitride nanoparticles effectively catalyze the conversion of LiPSs to Li2S, owing to their high electronic conductivity and strong binding power to LiPSs. Benefiting from this well crafted composite nanostructure, the constructed FexN C S cathode demonstrated a fairly high discharge capacity of 1085 mAh g 1 at 0.5 C initially, and a remaining value of 930 mAh g 1 after 200 cycles. In addition, it exhibits an excellent rate capability with a high initial discharge capacity of 889.8 mAh g 1 at 2 C. This facile PIL to nanocarbon synthetic approach is applicable for the exquisite design of complex hybrid carbon nanostructures with potential use in electrochemical energy storage and conversio
