Thermoelectric properties of lower concentration K-doped Ca3Co4O9 ceramics
Ya-Nan Li(李亚男)1, Ping Wu(吴平)1, Shi-Ping Zhang(张师平)1, Sen Chen(陈森)1, Dan Yan(闫丹)1, Jin-GuangYang(杨金光)1, Li Wang(王立)2, Xiu-Lan Huai(淮秀兰)3
1 Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China; 2 School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; 3 Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
Abstract The tuning of electron and phonon by ion doping is an effective method of improving the performances of thermoelectric materials. A series of lower concentration K-doped Ca3-xKxCo4O9 (x=0, 0.05, 0.10, 0.15) polycrystalline ceramic samples are prepared by combining citrate acid sol-gel method with cold-pressing sintering method. The single-phase compositions and plate-like grain morphologies of all samples are confirmed by x-ray diffraction and field emission scanning electron microscope. The effects of lower concentration K doping on the thermoelectric properties of the material are evaluated systematically at high temperatures (300-1026 K). Low concentration K doping causes electrical conductivity to increase up to 23% with little effect on the Seebeck coefficient. Simultaneously, the thermal conductivity of K-doped sample is lower than that of the undoped sample, and the total thermal conductivity reaches a minimum value of approximately 1.30 W·m-1·K-1, which may be suppressed mainly by the phonon thermal conduction confinement. The dimensionless figure-of-merit ZT of Ca2.95K0.05Co4O9 is close to 0.22 at 1026 K, representing an improvement of about 36% compared with that of Ca3Co4O9, suggesting that lower concentration K-doped Ca3Co4O9 series materials are promising thermoelectric oxides for high-temperature applications.
(Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides))
Fund: Project supported by the National Key R&D Program of China (Grant No.2016YFB0601101) and the National Natural Science Foundation of China (Grant No.51476173).
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.
