基于第一性原理计算的SOEC双钙钛矿型氢电极材料设计及电极反应动力学研究

Key materials of solid oxide electrolysis cell (SOEC) is currently a research hotspot in the new energy material domain. However, Ni-YSZ cermet is still the typical hydrogen electrode material applied in SOEC. Although this material has a high electrical conductivity and some other advantages, there are still unsolved problems, such as aggregation of Ni caused by high temperature and high humidity, evaporation of Ni at high temperature, poisoning by impurities in the materials, etc. Double-perovskite oxides, which have unique crystal structures and generally have advantages like high catalytic activity, stable structure, redox stability, etc., can be a potential alternative hydrogen electrode material applied in SOEC. This project attempts to develop a double-perovskite-structured hydrogen electrode material which is more applicable to the special working environment of SOEC, and provides a new research idea in R&D of alternative hydrogen electrode materials for SOEC. To avoid the blindness of new materials R&D using "cooking method", this project is based on first-principle calculation, aims to predict material properties, purposefully design new hydrogen electrode materials, explore the reaction kinetics in the hydrogen electrode side, and establish theoretical basis of research on H2O(g) decomposition mechanism in double-perovskite hydrogen electrode of SOEC.

固体氧化物电解池（SOEC）关键材料是目前新能源材料领域的研究热点，但其氢电极材料仍以Ni-YSZ复合氢电极材料为主。该材料虽然具有高电导率等突出优点，但是也存在着诸如Ni高温高湿下易烧结团聚、Ni高温挥发、易杂质中毒等尚未解决的难题。双钙钛矿材料有独特的晶体结构，普遍具备结构稳定、氧化还原稳定、高混合电导、高催化活性等优点，是一种非常有希望替代Ni-YSZ的SOEC氢电极材料。本项目拟研发出一种更加适用于SOEC特殊工作环境的双钙钛矿结构氢电极新材料，为SOEC氢电极替代材料的研发提供一个新的研究思路。为避免“炒菜法”进行新材料研发的盲目性，特以第一性原理模拟计算为理论指导，预测材料的性能，有目的性地设计氢电极新材料，并深入探索氢电极侧电极反应动力学过程，为双钙钛矿材料作为SOEC氢电极催化H2O (g)分解机理的研究奠定理论基础。

本项目选择Sr2CoMoO6，Sr2CoNbO6，Sr2FeNbO6等几种双钙钛矿及其掺杂体系材料为研究对象，采用实验及第一性原理模拟计算研究了双钙钛矿材料本身的电性能、稳定性能以及作为SOEC氢电极材料催化分解水的电化学性能。实验研究及第一性原理模拟计算结果表明，Sr2FeNbO6电化学综合性能较好，是一种可以替代传统Ni-YSZ且更加适用于SOEC特殊工作环境下的双钙钛矿结构氢电极新材料。同时，根据第一性原理计算结果，我们揭示了氢电极侧电极反应动力学过程，提出了双钙钛矿材料作为SOEC氢电极催化分解H2O (g)机理。该项目结论及成果可为SOEC氢电极替代材料的研究提供实验依据及理论基础，相关研究思路及结论也可以用于SOFC电极材料的研发。