A high Rate, High Capacity and Long Life (LiFePO_4+AC)/Li_4Ti_5O_(12) Hybrid Battery-Supercapacitor

摘要

A hybrid battery-supercapacitor (LiFePO_4+AC)/Li_4Ti_5O_(12) using a Li_4Ti_5O_(12) anode and a LiFePO_4/activated carbon(AC) composite cathode was built. The electrochemical performances of the hybrid battery-supercapacitor (LiFePO_4+AC)/Li_4Ti_5O_(12) were characterized by constant current charge-discharge, rate charge-discharge, electrochemical impedance spectra, internal resistance, leakage current, self-discharge and cycle performance testing. The results show that (LiFePO_4+AC)/Li_4Ti_5O_(12) hybrid battery-supercapacitors have rapid charge-discharge performance, high energy density, long cycle life, low resistance, low leakage current and self-discharge rate, which meet the requirements of practical power supply and can be applied in auxiliary power supplies for hybrid electric vehicles. At 4C rate, the capacity loss of (LiFePO_4+AC)/Li_4Ti_5O_(12) hybrid battery-supercapacitors in constant current mode is no more than 7.71% after 2000 cycles, and the capacity loss in constant current- constant voltage mode is no more than 4.51% after 1500 cycles.