Xiang Duo, Gu Changdong, Xu Haoran, Deng Jiali, Zhu Peiwang, Xiao Gang
State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China.
State Key Laboratory of Silicon Materials, College of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China.
ACS Appl Mater Interfaces. 2021 Dec 8;13(48):57274-57284. doi: 10.1021/acsami.1c17592. Epub 2021 Nov 22.
Next-generation concentrated solar power plants with high-temperature energy storage requirements stimulate the pursuit of advanced thermochemical energy storage materials. Copper oxide emerges as an attractive option with advantages of high energy density and low cost. But its easy sinterability limits its reversibility and cyclic stability performance. In this work, aluminum-doped copper oxides are synthesized and evaluated via thermogravimetric analysis. The reversibility of Cu-Al oxides reaches 99.5% in the first redox cycle and maintains 81.1% of the initial capacity after 120 cycles. The Al element can modify the CuO particle surface in the form of CuAlO, which separates the copper oxide particles from each other during redox cycles to avoid agglomeration and participates in the redox reaction. Through DFT analysis, the introduction of Al is found to increase the formation energy of copper vacancies in copper oxides, which helps avoid the sintering problem and thus improves the oxidation rate. This study provides a generalizable operational mechanism of element doping and can serve as a guideline for the optimization of high-performance materials in thermochemical energy storage.
具有高温储能需求的下一代聚光太阳能发电厂刺激了对先进热化学储能材料的追求。氧化铜因其高能量密度和低成本的优势而成为一个有吸引力的选择。但其易于烧结的特性限制了其可逆性和循环稳定性性能。在这项工作中，通过热重分析合成并评估了铝掺杂的氧化铜。Cu-Al氧化物在第一个氧化还原循环中的可逆性达到99.5%，在120次循环后保持初始容量的81.1%。Al元素可以以CuAlO的形式修饰CuO颗粒表面，在氧化还原循环过程中将氧化铜颗粒彼此分离以避免团聚，并参与氧化还原反应。通过密度泛函理论（DFT）分析，发现Al的引入增加了氧化铜中铜空位的形成能，这有助于避免烧结问题，从而提高氧化速率。本研究提供了一种可推广的元素掺杂操作机制，并可作为热化学储能中高性能材料优化的指导方针。
