Aqueous slurry of S-doped carbon nanotubes as conductive additive for lithium ion batteries

S-doped carbon nanotubes (SCNTs) obtained by a post treatment approach are used as conductive additive for LiFePO4 (LFP) cathodes in Lithium ion batteries (LIBs). The SCNTs exhibit higher specific surface area, higher conductivity and better hydrophily as compared to the pristine CNTs because of S doping. Thus the SCNTs can be stably dispersed in water, forming an aqueous conductive slurry. The LFP cathode using the aqueous SCNTs slurry as conductive additive exhibits excellent electrochemical performances in terms of capacity (143 mA h g−1 at 2 C), rate capability and cycling stability (99.6% of initial capacity after 200 cycles) due to the uniform dispersibility of SCNTs in the bulk of electrodes forming a continuous conductive network. The full cell configuration with graphite as anode, affords a high reversible capability (150 mA h g−1 at 0.2 C), good cycling stability (capacity retention of 87.6% at 2 C), ultrahigh energy density of 163.7 W h kg−1 and power density of 296.8 W kg−1. Our results provide an easy approach to prepare high performance LIB cathodes using water as solvent, thus leading to lower cost and more secure for the electrode production.