Preparation and characteristics of Li4Ti5O12 with various dopants as anode electrode for hybrid supercapacitor

Spinel-Li4Ti5O12 is successfully synthesized by a solid phase synthesis. The Li4Ti5O12 powders with various dopants (Al3+, Cr3+, Mg2+) synthesized at 800 °C are in accordance with the Li4Ti5O12 cubic spinel phase structure. The dopants are inserted into the lattice structure of Li4Ti5O12 without causing any changes in structural characteristics. In order to study the effect on various dopants, the hybrid supercapacitor is prepared by using un-doped Li4Ti5O12 and doped Li4Ti5O12 in this work. The electrochemical performance of the hybrid supercapacitor is characterized by impedance spectroscopy and cycle performance. The results show Cr3+ and Mg2+ dopants enhance the conductivity of Li4Ti5O12. Also, Al3+ substitution improves the reversible capacity and cycling stability of Li4Ti5O12. It is found that effect of dopant on the electrochemical performance of Li4Ti5O12 as electrode material for hybrid supercapacitor where the EDLC and the Li ion secondary battery coexist in one cell system.