Design and characterization of asymmetric supercapacitor useful in hybrid energy storage systems for electric vehicles

Energy storage systems (ESSs) of electric vehicles (EVs) require high energy density and high power density concurrently. The ESSs with only supercapacitors (SCs) or high performance batteries (hpBs) have egregious limitations, and are unable to meet up the demands for specific power and energy concurrently. This study reports on the design and characterization of asymmetric supercapacitor based on activated carbon (ACC) and MoS2 that suitable for use in hybrid energy storage systems in electric vehicles. The contribution of the double storage mechanism processes obtained from the faradaic storage sulfide material (MoS2) combined with the excellent electric double layer storage from the activated carbon led to the overall realization of an specific energy of ~ 27.82 Wh kg-1 with a related specific power of 1000 W kg-1 at a 0.5 A g-1 gravimetric current density. In addition, the device also exhibited a 100% coulombic efficiency even after cycling for 10,000 continuous charge-discharge cycles serving as the highest reported presently on this device type. This shows the unique potential of adopting such ACC/MoS2 materials as exceptional candidates to act as SC cells in the hybrid system for energy storage in electric vehicles.