Effect of Lithiation Voltage Limit on the Electrochemical Performance of High Surface Area Anatase TiO2 Nanoparticles and Its Application in Full-Cell Li-Ion Battery

摘要

Titania based anodes have received considerable interest due to its cycling stability and improved safety. Here, we report the electrochemical performance of high surface area anatase TiO2 nanoparticles synthesized via solvothermal technique. Prepared anatase TiO2 nanoparticles were below 15 nm in average particle size exhibiting high surface area of 251 m(2)/g and titanium existing in 4+ oxidation state. The electrodes studied by limiting the discharge voltage between 1.0 V and 0.01 V showed significant performance differences. Especially, specific capacity, Coulombic efficiency and storage mechanism of TiO2 depends strongly on lithiation voltage cut-off limit that is discussed in detail. It was established that discharging to 1.0 V showed better performance hence, subsequent studies the lithiation (discharge) was limited to 1.0 V. High rate capability of the electrodes were tested test up to 60 C and long cycle stability up to 1000 cycles (at 10 C rate). As an energy storage solution, a 2.0 V full-cell Li-ion battery was fabricated with the TiO2 nanoparticles as anode against surface modified LiCoO2 as cathode. The full-cell delivered specific capacities about 165 mAh/g and 105 mAh/g at current densities of 150 mA/g and 3765 mA/g respectively. It also exhibited 126 mAh/g capacity and 85 retention at the end of 100 cycles at a current density of 1000 mA/g. The full-cell delivered a maximum power density of 5.5 kW/kg and a corresponding energy density of 185 Wh/kg.