Green synthesis of S-doped carbon nanotubes and their application as
conductive additive in Li ion batteries
Sulfur-doped carbon nanotubes (SCNTs) exhibit better conductivity and
hydrophilicity, as compared to the undoped carbon nanotubes (CNTs). Low
cost mass production of SCNTs is highly desirable for their real
application at an industrial scale. Here, scalable green syntheses of
SCNTs and S, N dual doped CNTs (SNCNTs) are demonstrated based on the
gaseous S doping using SO2 as dopant. The process not only significantly
promotes the hydrophilicity and conductivity of CNTs due to the
incorporation of S atoms in carbon framework, but also purifies the
final product due to burning off the carbon coatings of metal particles.
SO2 is generated by CaSO3 pyrolysis and absorbed by CaO, thus realize
the recycling of S species. The LiFePO4 cathodes using the as-prepared
SCNTs and SNCNTs as conductive additive exhibit enhanced capacity and
rate performance than the electrodes prepared with the pristine CNTs,
not matter using N-methyl pyrrolidone or water as solvent.