Abstract:
Aim at the problem of LiAlH
4 exist excessive hydrogen release temperature and slow hydrogen release kinetics as hydrogen storage material, a modification method that preparing NiTiO
3 and doping it into LiAlH
4through mechanical ball milling was proposed. The effect of NiTiO
3 on dehydrogenation properties of LiAlH
4 were studied by temperature programmed desorption and isothermal desorption experiments, and the results show that the initial hydrogen release temperature of the LiAlH
4 doped with
w(NiTiO
3)=6% decreases to 73 ℃, reduced by 120 ℃ compared to pristine LiAlH
4; in isothermal hydrogen release test, the LiAlH
4 of doping 6% NiTiO
3 at 180 ℃ can release
w(H
2)=4.70% in 60 min, pristine LiAlH
4 hardly release hydrogen under the same conditions. The results show activation energy of dehydrogenation of
w(NiTiO
3)=6% LiAlH
4 decreases to 71.56 kJ/mol for the first step and 122.49 kJ/mol for the second step, indicating for improving the kinetic performance of hydrogen release. Through XRD analysis, ball milling process destroy stability of NiTiO
3 and make it amorphization, while amorphous NiTiO
3 can provide active sites and increase hydrogen diffusion channels for dehydrogenation reaction of LiAlH
4. The experimental results show that the modification method doping NiTiO
3 effectively improve dehydrogenation properties of LiAlH
4.