Boosting the comprehensive behaviors of LiNi0.5Co0.2Mn0.3O2 lithium-ion batteries via CNTs/Super-P composite conductive agent

In this work, a conductive slurry containing CNTs is used as a modification reagent for the Super-P (SP) conductive agent. After CNTs is recombined with SP, spherical SP particles with a diameter of about 60 nm are evenly dispersed on the surface of CNTs nanotubes with a diameter of 20 nm, which effectively improves the specific surface area of the conductive agent. As a result, the battery using 1.5 % CNTs/SP composite conductive agent shows a smaller EIS impedance value, which makes the comprehensive behaviors of the LiNi0.5Co0.2Mn0.3O2 battery significantly improved. The CNTs/SP battery shows larger CV curve area and smaller potential difference between oxidation and reduction peaks. In addition, the initial charge and discharge capacity of CNTs/SP battery are 181.7 and 184.7 mAh/g respectively with initial Coulombic efficiency of 98.4%, which are much higher than the pristine SP battery (173.7 and 182.0 mAh/g respectively with initial Coulombic efficiency of 95.4 %). After 70 cycles, the discharge capacity of CNTs/SP battery can still remain at 175.3 mAh/g with capacity retention ratio of 97.2 %, which are also much higher than the pristine SP battery (142.5 mAh/g with capacity retention ratio of 82.8 %). Moreover, compared with the pristine SP batteries, the CNTs/SP batteries show larger discharge capacities at different rates of 0.2 C, 0.5 C, 1.0 C, 2.0 C, 3.0 C and 5.0 C. After combining SP with CNTs nanowires, the discharge capacity, initial coulombic efficiency, cycle stability and rate capability of LiNi0.5Co0.2Mn0.3O2 electrode are effectively improved, which provides a new idea for the development of novel conductive agent for high-performance cathode materials of lithium ion batteries.