P掺杂β-FeSi2材料的制备与热电输运性能
Preparation and Thermoelectric Transport Properties of P-doped β-FeSi2
程俊 1张家伟 1仇鹏飞 2陈立东 1史迅1
作者信息
- 1. 中国科学院 上海硅酸盐研究所,高性能陶瓷和超微结构国家重点实验室,上海 200050;中国科学院大学材料科学与光电技术学院,北京 100049
- 2. 中国科学院 上海硅酸盐研究所,高性能陶瓷和超微结构国家重点实验室,上海 200050;中国科学院大学材料科学与光电技术学院,北京 100049;中国科学院大学 杭州高等研究院,化学与材料科学学院,杭州 310024
- 折叠
摘要
β-FeSi2 作为一种绿色环保、高温抗氧化的热电材料,在工业余热回收领域具有潜在的应用价值.虽然磷(P)是一种理想的β-FeSi2 硅(Si)位的n型掺杂元素,但是P掺杂β-FeSi2 易出现第二相,从而限制了其热电性能的提升.本研究采用感应熔炼法合成了一系列FeSi2-xPx(x=0,0.02,0.04,0.06)样品,极大程度地避免了第二相的产生,并系统研究了P掺杂对β-FeSi2 热电输运性能的影响.结果表明,P在β-FeSi2 中的掺杂极限约为 0.04,与前期的理论缺陷计算结果相符.此外,P掺杂优化了β-FeSi2的热电性能,在850 K时,FeSi1.96P0.04的最高热电优值ZT约为0.12,远高于已有的研究结果(673 K,最高ZT仅为 0.03).然而,与同为n型Co和Ir掺杂的β-FeSi2 相比(其载流子浓度可达 1022 cm-3),P掺杂β-FeSi2 的载流子浓度较低,最高仅为 1020 cm-3,这导致其电声散射效应较弱,从而限制了整体热电性能的提升.若能提高其载流子浓度,则热电性能有望得到进一步提升.
Abstract
β-FeSi2,an environmentally friendly and high temperature oxidation-resistant thermoelectric material,has potential applications in the field of industrial waste heat recovery.Previous studies have shown that phosphorus(P),an ideal n-type dopant in the silicon(Si)site of β-FeSi2,can easily lead to the formation of a secondary phase,thereby limiting the enhancement of thermoelectric performance.In this study,a series of FeSi2-xPx(x=0,0.02,0.04,0.06)samples were synthesized using an induction melting method,which greatly inhibited the formation of the secondary phase.Then,the influence of P doping on the electrical and thermal transport properties of β-FeSi2 was studied.The results indicate that the solubility limit of P in β-FeSi2 is about 0.04,consistent with earlier theoretical predictions based on the defect formation energy.It is also discovered that P doping enhanced the thermoelectric performance of β-FeSi2,culminating in an optimal figure of merit(ZT)of FeSi1.96P0.04 approximately 0.12 at 850 K,which is much higher than the previous results(ZT about 0.03 at 673 K).However,compared to β-FeSi2 doped with other n-type elements like cobalt(Co)and iridium(Ir),which can achieve carrier concentrations up to 1022 cm-3,P-doped β-FeSi2 exhibits lower carrier concentrations,with the highest of only 1020 cm-3.This results in a weaker electron-phonon scattering effect,which in turn constrains the overall enhancement of the thermoelectric performance.If the carrier concentration could be further increased,the thermoelectric performance of the material is expected to evolve significantly.
关键词
β-FeSi2/热电材料/P掺杂/感应熔炼/载流子浓度/电声散射Key words
β-FeSi2/thermoelectric material/P doping/induction melting/carrier concentration/electron-phonon scattering引用本文复制引用
基金项目
国家自然科学基金(52122213)
国家重点研发计划(2023YFB3809400)
出版年
2024
国家科技期刊平台
NSTL
万方数据