Palade Petru, Comanescu Cezar, Radu Cristian
National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania.
Faculty of Physics, University of Bucharest, Atomiștilor 405, 77125 Magurele, Romania.
Materials (Basel). 2023 Jan 2;16(1):427. doi: 10.3390/ma16010427.
Featuring a high hydrogen storage content of up to 20 wt%, complex metal borohydrides remain promising solid state hydrogen storage materials, with the real prospect of reversible behavior for a zero-emission economy. However, the thermodynamic barriers and sluggish kinetics are still barriers to overcome. In this context, nanoconfinement has provided a reliable method to improve the behavior of hydrogen storage materials. The present work describes the thermodynamic and kinetic enhancements of LiBH nanoconfined in MFeO (M=Co, Ni) ferrite-catalyzed graphene host. Composites of LiBH-catalysts were prepared by melt infiltration and investigated by X-ray diffraction, TEM, STEM-EDS and TPD. The role of ferrite additives, metal precursor treatment (Ar, Ar/H) and the effect on hydrogen storage parameters are discussed. The thermodynamic parameters for the most promising composite LiBH-graphene-NiFeO (Ar) were investigated by Kissinger plot method, revealing an E = 127 kJ/mol, significantly lower than that of neat LiBH (170 kJ/mol). The reversible H content of LiBH-graphene-NiFeO (Ar) after 5 a/d cycles was ~6.14 wt%, in line with DOE's target of 5.5 wt% storage capacity, while exhibiting the lowest desorption temperature peak of 349 °C. The composites with catalysts treated in Ar have lower desorption temperature due to better catalyst dispersion than using H/Ar.
复合金属硼氢化物具有高达20 wt%的高储氢含量，仍然是很有前景的固态储氢材料，有望实现零排放经济下的可逆行为。然而，热力学障碍和缓慢的动力学仍是需要克服的障碍。在此背景下，纳米限域为改善储氢材料的性能提供了一种可靠的方法。本工作描述了限域在MFeO（M = Co、Ni）铁氧体催化的石墨烯主体中的LiBH的热力学和动力学增强。通过熔体浸渗制备了LiBH - 催化剂复合材料，并通过X射线衍射、透射电子显微镜、扫描透射电子显微镜 - 能谱和程序升温脱附进行了研究。讨论了铁氧体添加剂的作用、金属前驱体处理（Ar、Ar/H₂）以及对储氢参数的影响。通过基辛格曲线法研究了最有前景的复合材料LiBH - 石墨烯 - NiFeO（Ar）的热力学参数，结果表明其活化能E = 127 kJ/mol，显著低于纯LiBH的活化能（170 kJ/mol）。LiBH - 石墨烯 - NiFeO（Ar）在5次吸/放氢循环后的可逆氢含量约为6.14 wt%，符合美国能源部5.5 wt%的储氢容量目标，同时其最低脱附温度峰值为349 °C。与使用H₂/Ar处理的催化剂相比，用Ar处理的催化剂制备的复合材料由于具有更好的催化剂分散性，因而具有更低的脱附温度。
