Synthesis and electrochemical properties of Li4Ti5O12 spheres and its application for hybrid supercapacitors

There is a growing demand for hybrid supercapacitor systems to combine the advantages of both lithium-ion battery and supercapacitors for the application of electric vehicles. We describe in this paper one kind of hybrid supercapacitor comprising spherical Li4Ti5O12 as negative electrode and activated carbon (AC) as positive electrode in the non-aqueous electrolyte. The Li4Ti5O12 spheres were synthesized using a LiCl-KCl molten-salt method and TiO2 spheres as the template. The Li4Ti5O12 spheres revealed high discharge capacity (168 mAh g−1 at 0.2 C), and a good capacity retention with high coulombic efficiency after cycling, which can be potential anode material for lithium ion batteries and negative material for hybrid supercapacitor. The AC//LTO hybrid supercapacitor exhibits excellent capacity retention of 93% after 500 cycles and offers higher energy density and power density than the AC//AC symmetric supercapacitor. The presented AC//LTO hybrid supercapacitor could be a competitive candidate for the promising energy storage devices.