Superior catalytic effect of titania - porous carbon composite for the storage of hydrogen in MgH2 and lithium in a Li ion battery

Abstract

A novel nanocomposite (0.2TiO2 + AC) with two promising applications is demonstrated, (i) as an additive for promoting hydrogen storage in magnesium hydride, (ii) as an active electrode material for hosting lithium in Li ion batteries (surface area of activated carbon (AC): 491 m2/g, pore volume: 0.252 cc/g, size of TiO2 particles: 20–30 nm). Transmission electron microscopy study provides evidence that well dispersed TiO2 nanoparticles are enclosed by amorphous carbon nets. A thermogravimetry-differential scanning calorimetry (TG-DSC) study proves that the nanocomposite is thermally stable up to ∼400 °C. Volumetric hydrogen storage tests and DSC studies further prove that a 3 wt% of 0.2TiO2+AC nanocomposite as additive not only lowers the dehydrogenation temperature of MgH2 over 100 °C but also maintains the performance consistency. Moreover, as a working electrode for Li ion battery, 0.2TiO2+AC offers a reversible capacity of 400 mAh/g at the charge/discharge rate of 0.1C and consistent stability up to 43 cycles with the capacity retention of 160 mAh/g at 0.4C. Such cost effective-high performance materials with applications in two promising areas of energy storage are highly desired for progressing towards sustainable energy development.