Entering new era of thermoelectric oxide ceramics with high power factor through designing grain boundaries
Entering new era of thermoelectric oxide ceramics with high power factor through designing grain boundaries
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DOI：
10.1016/j.rser.2023.113186
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发表时间：
2023-04
影响因子：
15.9
通讯作者：
Cesar-Octavio Romo-De-La-Cruz;Yun Chen;Liang Liang-Liang;Sergio A. Paredes-Navia;W. Wong-Ng;Xueyan Song
中科院分区：
文献类型：
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作者：
Cesar-Octavio Romo-De-La-Cruz;Yun Chen;Liang Liang-Liang;Sergio A. Paredes-Navia;W. Wong-Ng;Xueyan Song
热电氧化物陶瓷可以在利用热电发电机回收废热、加速清洁能源发电和实现净零排放方面发挥重要作用。2003年对单晶Ca3Co4O9+δ的热电性能进行了评价，其无因次热电优值（ZT）为0.87。由于多晶Ca3Co4O9+δ陶瓷具有低导电性和低塞贝克系数，因此其效率通常只有单晶的30%左右。为了提高Ca3Co4O9+δ多晶的热电性能，采用了一种独特的方法来驱动掺杂剂在晶界处的偏析，从而显著提高了氧化物的塞贝克系数、电导率和总能量转换效率。这篇综述利用了我们从五组掺杂剂中得到的相关结果，阐明了可以通过设计晶界来扭转它们对电性能的有害影响，并提供了显著改善电输运性能的设计领域。设计晶界的方法可用于选择适当尺寸的掺杂剂，最终使氧化物陶瓷的性能优于单晶。本文揭示了掺杂物晶界偏析的原子结构根源，提出了一种可行而有价值的方法，将晶界视为具有比晶内塞贝克系数高数量级的二维晶间二次相。这种晶间二次相的颜色可以独立调节，以解耦强相关的物理参数，同时在很宽的温度范围内提高塞贝克系数、电功率因数和z2。
Thermoelectric oxide ceramics could play a significant role in waste heat recovery using thermoelectric generators, accelerating clean energy generation and achieving net-zero emissions. In 2003, the thermoelectric performance of single-crystal Ca3Co4O9+δwas evaluated with a dimensionless thermoelectric figure-of-merit (ZT) of 0.87. Polycrystalline Ca3Co4O9+δceramics are typically only about 30% as efficient as single crystals since they have low electrical conductivity and low Seebeck coefficient. To improve the thermoelectric performance of polycrystalline Ca3Co4O9+δ, a unique approach was developed to drive dopants segregation at the grain boundaries to dramatically increase the Seebeck coefficient and electrical conductivity and total energy conversion efficiency of the oxide. This review exploited our pertinent results from five sets of dopants to elucidate that the grain boundary can be engineered to reverse their detrimental impact on electrical properties and provide the design domain to improve the electrical transport properties significantly. The approach to engineer the grain boundary can be used for the selection of dopants with the appropriate size that will ultimately result in oxide ceramics outperforming single-crystals. The present review unveils the atomic structure origin of the dopant segregation at grain boundaries and presents a feasible and valuable approach for treating the grain boundaries as a two-dimensional intergranular secondary phase complexion that is with magnitudes higher Seebeck coefficient than that of the intragrains. Such intergranular secondary phase complexion is independently tunable to decouple the strongly correlated physical parameters and simultaneously enhance the Seebeck coefficient, electrical power factor, andZTover a broad temperature range.