Improved Dehydrogenation Properties of LiBH₄ Using Catalytic Nickel- and Cobalt-based Mesoporous Oxide Nanorods

Lithium borohydride (LiBH₄ ) with a theoretical hydrogen storage capacity of 18.5 wt % has attracted intense interest as a high-density hydrogen storage material. However, high dehydrogenation temperatures and limited kinetics restrict its practical applications. In this study, mesoporous nickel- and cobalt-based oxide nanorods (NiCo₂ O₄ , Co₃ O₄ and NiO) were synthesized in a controlled manner by using a hydrothermal method and then mixed with LiBH₄ by ball milling. It is found that the dehydrogenation properties of LiBH₄ are remarkably enhanced by doping the as-synthesized metal oxide nanorods. When the mass ratio of LiBH₄ and oxides is 1:1, the NiCo₂ O₄ nanorods display the best catalytic performance owing to the mesoporous rod-like structure and synergistic effect of nickel and cobalt active species. The initial hydrogen desorption temperature of the LiBH₄ -NiCo₂ O₄ composite decreases to 80 °C, which is 220 °C lower than that of pure LiBH₄ , and 16.1 wt % H₂ is released at 500 °C for the LiBH₄ -NiCo₂ O₄ composite. Meanwhile, the composite also exhibits superior dehydrogenation kinetics, which liberates 5.7 wt % H₂ within 60 s and a total of 12 wt % H₂ after 5 h at 400 °C. In comparison, pure LiBH₄ releases only 5.3 wt % H₂ under the same conditions.