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

Highlights: • Li₄Ti₅O₁₂ (LTO) spheres are prepared by molten-salt and TiO₂ spheres as template. • The LTO spheres are potential for using as anode for AC//LTO hybrid capacitor. • The AC//LTO hybrid supercapacitor presents good electrochemical performance. - Abstract: 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