This study explores how the chemical interaction between magnesium hydride (MgH) and the additive CrO influences the hydrogen/lithium storage characteristics of MgH. We have observed that a 5 wt.% CrO additive reduces the dehydrogenation activation energy of MgH by 68 kJ/mol and lowers the required dehydrogenation temperature by 80 °C. CrO added MgH was also tested as an anode in an Li ion battery, and it is possible to deliver over 90% of the total theoretical capacity (2038 mAh/g). Evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH. In depth characterization study by X-ray diffraction (XRD) technique provides convincing evidence that the CrO additive interacts with MgH and produces Cr / MgO byproducts. Gibbs free energy analyses confirm the thermodynamic feasibility of conversion from MgH/CrO to MgO/Cr, which is well supported by the identification of Cr(0) in the powder by X ray photoelectron spectroscopy (XPS) technique. Through high resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt nanoparticles. There is also convincing ground to consider that MgO rock salt accommodates Cr in the lattice. These observations support the argument that creation of active metal – metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH, both for the improved storage of hydrogen and lithium.

中文翻译：

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了解三氧化铬添加氢化镁对储氢和锂离子电池应用的催化作用

本研究探讨了氢化镁 (MgH) 与添加剂 CrO 之间的化学相互作用如何影响 MgH 的氢/锂存储特性。我们观察到，5 wt.% CrO 添加剂可将 MgH2 的脱氢活化能降低 68 kJ/mol，并将所需的脱氢温度降低 80 °C。添加了 MgH 的 CrO 也作为锂离子电池的阳极进行了测试，可以提供超过 90% 的总理论容量（2038 mAh/g）。只有在添加了 MgH 添加剂后，才发现电池反应可逆性得到改善的证据。通过 X 射线衍射 (XRD) 技术进行的深入表征研究提供了令人信服的证据，证明 CrO 添加剂与 MgH 相互作用并产生 Cr / MgO 副产品。吉布斯自由能分析证实了从 MgH/CrO 转化为 MgO/Cr 的热力学可行性，并通过 X 射线光电子能谱 (XPS) 技术鉴定粉末中的 Cr(0) 得到了很好的支持。通过高分辨率透射电子显微镜 (HRTEM) 和能量色散光谱 (EDS)，我们发现了 MgO 岩盐纳米颗粒表面存在 5 nm 尺寸的 Cr 纳米晶体的证据。还有令人信服的理由认为 MgO 岩盐在晶格中容纳了 Cr。这些观察结果支持这样的论点：活性金属-金属溶解岩盐氧化物界面的形成对于提高 MgH2 的反应性可能至关重要，同时对于改善氢和锂的储存也至关重要。