Preparation and research of electrochemical performance of new LiFePO_4/AC hybrid supercapacitor

The LiFePO4/AC hybrid supercapacitor using LiFePO4 as positive electrode and the activated carbon(AC) as negative electrode was assembled.Electrochemical performance was studied through testing of charge and discharge,various discharge rates and leakage current.With the mass ratio of 0.8∶1.0 of active materials in the positive electrode and the negative electrode,the results show that the hybrid supercapacitor has the best comprehensive performance.Specific capacity and specific energy of as-prepared supercacpacitors reach 25.38 mAh·g-1 and 3.21 Wh·kg-1,and are 2.83 times and 2.17 times of activated carbon supercapacitor respectively.The hybrid supercapacitors possess good rate charge and discharge properties.Cycle stability of LiFePO4/AC hybrid supercapacitor is fine and leakage current is small under high discharge rates.Leakage current of hybrid supercapacitor is 0.25 mA after 1 600 s.