Structural, Optical, and Temperature-Dependent Electrical Transport Properties of Li4Ti5O12-Li2TiO3 Heterostructured Anode for Energy Storage
摘要
Li4Ti5O12-Li2TiO3 exhibits distinct phases of Li4Ti5O12 and Li2TiO3 in its heterostructure. Morphological analysis reveals highly crystalline samples with average particle size of 0.3–0.5 µm. A wide bandgap of 3.6 eV predicts low electronic conductivity of the composite. Both pure and composite samples exhibit oxidation states of +4 for Ti ions. Room-temperature electronic and ionic conductivity of 3.9 × 10−8 S cm−1 and 7 × 10−8S cm−1 for Li4Ti5O12 decrease slightly to 2 × 10−8S cm−1 and 4.5 × 10−8S cm−1 for the composite. In a temperature range of 20–300°C the heterostructure demonstrates increased conductivity from 10−8S cm−1 to 10−5S cm−1 in both grains and grain boundaries, attributed to increased interfaces. Arrhenius plots exhibit low activation energy of 0.32 eV for the composite. The structural and electrical properties of Li4Ti5O12-Li2TiO3 strongly influence its electrochemical performance as an anode.