In Situ AlNi Derived From Ni/Dual‐Phase TiO2 for Hydrogen Storage Enhancement of MgH2

Why It Matters

The breakthrough lowers the temperature and energy barriers for MgH₂‑based hydrogen storage, making solid‑state systems more viable for commercial clean‑energy applications.

Key Takeaways

• 10 wt% Ni/Dp‑TiO₂ raises MgH₂ absorption to 4.28 wt% at 150 °C
• Desorption reaches 3.86 wt% H₂ at 250 °C within 2500 s
• Activation energy drops to 56 kJ mol⁻¹, enabling lower‑temperature operation
• AlNi/Dp‑TiO₂ acts as electron‑transfer medium, accelerating kinetics
• Combined Al phases lower hydrogenation and dehydrogenation enthalpies

Pulse Analysis

Magnesium hydride has long been hailed for its high gravimetric hydrogen capacity, yet its practical deployment has been hampered by slow absorption/desorption rates and the need for temperatures above 300 °C. Researchers have therefore pursued alloying and catalytic strategies to unlock MgH₂’s potential. By integrating nickel nanoparticles onto a mixed‑phase TiO₂ support and embedding this composite into an Al‑doped Mg matrix, the study creates an in‑situ AlNi/TiO₂ network that serves as an efficient electron conduit, directly addressing the kinetic bottleneck.

The experimental results are striking: a 10 wt% loading of Ni/Dp‑TiO₂ enables the Mg₉₀Al₁₀‑10 wt% catalyst to absorb 4.28 wt% hydrogen at just 150 °C and to release 3.86 wt% at 250 °C within a modest 2,500 seconds. This performance dwarfs the untreated alloy, which manages less than 1 wt% under the same conditions. The dehydrogenation activation energy collapses to 56 kJ mol⁻¹, and both hydrogenation and dehydrogenation enthalpies are reduced, reflecting a more favorable thermodynamic profile. Density functional theory calculations confirm that the AlNi/TiO₂ phase facilitates electron transfer, while Al‑rich intermetallics (Mg‑Al solid solution, Mg₁₇Al₁₂, Mg₂Al₃) further stabilize hydrogen intermediates.

For the broader hydrogen economy, such catalyst designs could shift solid‑state storage from a laboratory curiosity to a market‑ready technology. Lower operating temperatures translate to reduced system complexity, lighter thermal management, and lower overall cost—key criteria for automotive and grid‑scale applications. Future work will likely explore scaling the synthesis, integrating the catalyst into bulk MgH₂ modules, and pairing it with renewable hydrogen production to create closed‑loop, low‑carbon energy storage solutions.