Doppiu Stefania, Dauvergne Jean-Luc, Palomo Del Barrio Elena
Centro de Investigación Cooperativa de Energías Alternativas, CIC energiGUNE, 01510 Vitoria-Gasteiz, Spain.
Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain.
Nanomaterials (Basel). 2019 Feb 7;9(2):226. doi: 10.3390/nano9020226.
In this paper, the use of solid-state reactions for the storing of thermal energy at high temperature is proposed. The candidate reactions are eutectoid- and peritectoid-type transitions where all the components (reactants and reaction products) are in the solid state. To the best of our knowledge, these classes of reactions have not been considered so far for application in thermal energy storage. This study includes the theoretical investigation, based on the Calphad method, of binary metals and salts systems that allowed to determine the thermodynamic properties of interest such as the enthalpy, the free energy, the temperature of transition, the volume expansion and the heat capacity, giving guidelines for the selection of the most promising materials in view of their use for thermal energy storage applications. The theoretical investigation carried out allowed the selection of several promising candidates, in a wide range of temperatures (300⁻800 °C). Moreover, the preliminary experimental study and results of the binary Mn-Ni metallic system are reported. This system showed a complex reacting behavior with several discrepancies between the theoretical phase diagram and the experimental results regarding the type of reaction, the transition temperatures and enthalpies and the final products. The discrepancies observed could be due both to the synthesis method applied and to the high sensitivity of the material leading to partial or total oxidation upon heating even if in presence of small amount of oxygen (at the ppm level).
本文提出利用固态反应在高温下储存热能。候选反应是共析和包析型转变，其中所有组分（反应物和反应产物）均处于固态。据我们所知，这类反应迄今尚未被考虑用于热能储存。本研究包括基于相图计算（Calphad）方法对二元金属和盐体系进行理论研究，从而确定诸如焓、自由能、转变温度、体积膨胀和热容等相关热力学性质，为选择最有前景的材料用于热能储存应用提供指导。通过进行理论研究，在较宽温度范围（300⁻800 °C）内筛选出了几种有前景的候选材料。此外，还报道了二元Mn-Ni金属体系的初步实验研究及结果。该体系表现出复杂的反应行为，在反应类型、转变温度和焓以及最终产物方面，理论相图与实验结果存在若干差异。观察到的差异可能是由于所采用的合成方法以及该材料的高敏感性所致，即使存在少量氧气（ppm级别），加热时材料也会发生部分或完全氧化。
