Piperopoulos Elpida, Fazio Marianna, Mastronardo Emanuela, Lanza Maurizio, Milone Candida
Department of Engineering, University of Messina, 98166 Messina, Italy.
National Interuniversity Consortium of Materials Science and Technology (INSTM), 50121 Florence, Italy.
Materials (Basel). 2021 Feb 26;14(5):1091. doi: 10.3390/ma14051091.
Thermochemical materials (TCM) are among the most promising systems to store high energy density for long-term energy storage. To be eligible as candidates, the materials have to fit many criteria such as complete reversibility of the reaction and cycling stability, high availability of the material at low cost, environmentally friendliness, and non-toxicity. Among the most promising TCM, the Mg(OH)/MgO system appears worthy of attention for its properties in line with those required. In the last few decades, research focused its attention on the optimization of attractive hydroxide performance to achieve a better thermochemical response, however, often negatively affecting its energy density per unit of volume and therefore compromising its applicability on an industrial scale. In this study, pure Mg(OH) was developed using different synthesis procedures. Reverse deposition precipitation and deposition precipitation methods were used to obtain the investigated samples. By adding a cationic surfactant (cetyl trimethylammonium bromide), deposition precipitation Mg(OH) (CTAB-DP-MH) or changing the precipitating precursor (N-DP-MH), the structural, physical and morphological characteristics were tuned, and the results were compared with a commercial Mg(OH) sample. We identified a correlation between the TCM properties and the thermochemical behavior. In such a context, it was demonstrated that both CTAB-DP-MH and N-DP-MH improved the thermochemical performances of the storage medium concerning conversion (64 wt.% and 74 wt.% respectively) and stored and released heat (887 and 1041 kJ/kgMg(OH)2). In particular, using the innovative technique not yet investigated for thermal energy storage (TES) materials, with NaOH as precipitating precursor, N-DP-MH reached the highest stored and released heat capacity per volume unit, ~684 MJ/m.
热化学材料（TCM）是用于长期储能的最具潜力的系统之一，能够存储高能量密度。要成为合格的候选材料，这些材料必须符合许多标准，例如反应的完全可逆性和循环稳定性、低成本下材料的高可用性、环境友好性和无毒。在最有前景的热化学材料中，Mg(OH)/MgO体系因其符合所需性能而值得关注。在过去几十年中，研究主要集中在优化有吸引力的氢氧化物性能以实现更好的热化学反应，然而，这往往会对其单位体积的能量密度产生负面影响，从而影响其在工业规模上的适用性。在本研究中，使用不同的合成方法制备了纯Mg(OH)。采用反向沉积沉淀法和沉积沉淀法获得了研究样品。通过添加阳离子表面活性剂（十六烷基三甲基溴化铵）、沉积沉淀Mg(OH)（CTAB-DP-MH）或改变沉淀前驱体（N-DP-MH），对结构、物理和形态特征进行了调整，并将结果与商业Mg(OH)样品进行了比较。我们确定了热化学材料性能与热化学行为之间的相关性。在这种情况下，结果表明，CTAB-DP-MH和N-DP-MH均提高了储能介质在转化方面的热化学性能（分别为64 wt.%和74 wt.%）以及储存和释放的热量（887和1041 kJ/kgMg(OH)2）。特别是，使用尚未用于热能存储（TES）材料研究的创新技术，以NaOH作为沉淀前驱体，N-DP-MH达到了最高的单位体积储存和释放热容量，约为684 MJ/m。
