Nanoflower-engineered Co₃O₄@CoNi-LDO bimetallic oxide: A catalyst for revolutionizing hydrogen storage in LiAlH₄

The inherent thermodynamic stability and slow kinetics of LiAlH₄ pose significant challenges for its practical application in hydrogen storage. This study addresses these limitations by introducing nanoflower-structured layered double oxides (Co₃O₄@CoNi-LDO) as a performance-enhancing catalyst. The Co₃O₄@CoNi-LDO was synthesized through a hydrothermal process followed by calcination and subsequently incorporated into LiAlH₄ via mechanical ball milling. Experimental results demonstrate that the addition of 7 wt% Co₃O₄@CoNi-LDO substantially improves the hydrogen desorption properties of LiAlH₄. The hydrogen release temperatures for the two-step desorption process are reduced to 85.1 °C and 177.0 °C, respectively, with a total hydrogen release of approximately 6.87 wt% below 300 °C. Moreover, the activation energy of the two desorption steps is lowered by 20.0% and 46.3% compared to pristine LiAlH₄. The modified material also exhibits superior rehydrogenation performance, absorbing approximately 0.64 wt% hydrogen within 5 h-markedly better than pristine LiAlH₄. Mechanistic studies reveal that the in-situ formation of catalytically active species, such as Al₁₃Co₄ and Al₀.₉Ni₄.₂₂, anchored on the LiAlH₄ matrix, plays a pivotal role in facilitating hydrogen transfer. These catalytic sites effectively reduce the energy barriers for hydrogen desorption, enhancing the kinetics of the process. This work highlights the potential of Co₃O₄@CoNi-LDO nanoflowers as a highly effective catalyst for improving the hydrogen storage capabilities of LiAlH₄, paving the way for its application in advanced energy storage systems.