Li_4Ti_5O_(12) was synthesized by a facile gel-combustion method(GCM) with polyvinylpyrrolidone(PVP) as the polymer chelating agent and fuel.The structural and electrochemical properties of the sample were compared with the one prepared by the conventional solid-state reaction(SSR) through X-ray diffraction(XRD),scanning electron microscopy(SEM),cyclic voltammetry(CV),charge-discharge measurements,and electrochemical impedance spectroscopy(EIS),respectively.The sub-microscale Li_4Ti_5O_(12) oxides,with a high phase purity and good stoichiometry,can be obtained by annealing at 800 C.The grain size is smaller than that of the samples that were power prepared by SSR.Lithium-ion batteries with a GCM Li_4Ti_5O_(12) anode exhibit excellent reversible capacities of 167.6,160.7,152.9,and 144.2 mAh/g,at the current densities of 0.5 C,1 C,3 C and 5 C,respectively.The excellent cycling and rate performance can be attributed to the smaller particle size,lower charge-transfer resistance and larger lithium ion diffusion coefficient.It is therefore concluded that GCM Li_4Ti_5O_(12) is a promising candidate for applications in highrate lithium ion batteries.
