Improved electrochemical performance of hybrid supercapacitor using Zr doped Li4Ti5O12 anode

Abstract

The cylindrical hybrid supercapacitors are fabricated using the activated carbon as the cathode and Li4Ti5-xZrxO12 (0 <= x <= 0.6) as the anode. The x-ray diffraction patterns of the Li4Ti5-xZrxO12 (0 <= x < 0.6) exhibited that Zr entered into the Ti-site and the Li4Ti5-xZrxO12 (0 <= x <= 0.45) was well-crystallized without secondary phases. This increased lattice parameter and conductivity of Li4Ti5O12. However excessive Zr doping caused inferior electrochemical performance due to impurity phases. The bigger CV region of Li4Ti5-xZrxO12 (0.15 <= x <= 0.45) can be inferred that Zr leads more active electrochemical performance than that of Li4Ti5O12. The Zr also improved the initial charge-discharge capacitance as well as cycling stability. The hybrid supercapacitor using Li4Ti4.55Zr0.45O12 anode shows the most excellent electrochemical performance.