发表机构
Indian Institute of Technology Bhilai; Université Paris-Saclay（印度理工学院比莱分校; 巴黎萨克雷大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过组分工程调控LaCoO3基高熵钙钛矿的阳离子种类与浓度，而非仅最大化构型熵，实现了声子与电子输运的解耦；其中非等摩尔B位组分在保持低热导率的同时降低极化子跳跃势垒，使功率因子和热电优值显著提升至等摩尔类似物的约2.7倍。
AI 中文摘要
声子和电子输运的解耦仍然是开发高性能热电材料的核心挑战。构型熵最大化被广泛用作解耦声子和电子输运的设计原则。本研究探讨了组分工程化的LaCoO$_3$基高熵钙钛矿，以确定是否可以通过调节阳离子种类和浓度而非最大化构型熵来改善热电输运。通过固相反应制备了La$_{1-x}$Sr$_x$(CoFeMnCrNi)O$_3$（$x=0.0$--$0.2$）以及选定的非等摩尔A位和B位钙钛矿组分。所得样品主要为单相，经X射线衍射和Rietveld精修确认，与计算的尺寸无序参数一致。多阳离子无序引入了显著的质子和应变场波动，促进了声子散射。所有样品均表现出p型、热激活的电输运行为，与绝热小极化子跳跃模型一致。Sr取代逐渐降低跳跃势垒和电阻率，而非等摩尔B位工程在保持低热导率的同时部分恢复了电输运。La$_{0.9}$Sr$_{0.1}$Co$_{0.4}$Cr$_{0.3}$Ni$_{0.1}$Fe$_{0.1}$Mn$_{0.1}$O$_3$具有富Co和富Cr的B位组分，结合了Co相关的混合价态和自旋态简并，维持了较大的Seebeck系数，同时通过Cr调控载流子浓度，并将极化子跳跃势垒降低至0.19 eV。该组分在1100 K下实现了40--43 $μ$W/(m K$^2$)的功率因子和$zT\sim0.072$，约为其等摩尔类似物的2.7倍。这些结果表明，针对性的阳离子化学和质量对比，而非仅靠构型熵最大化，为多组分氧化物热电材料中平衡电子和声子输运提供了有效策略。
英文摘要
The decoupling of phonon and electron transport remains a central challenge in the development of high-performance TE materials. Configurational-entropy maximization is widely invoked as a design principle for decoupling phonon and electron transport. This study investigates compositionally engineered LaCoO$_3$-based high-entropy perovskites to determine whether thermoelectric transport can be improved by tuning cation identity and concentration rather than maximizing configurational entropy. La$_{1-x}$Sr$_x$(CoFeMnCrNi)O$_3$ ($x=0.0$--$0.2$) and selected non-equimolar A- and B-site perovskite compositions were prepared by solid-state reaction. The obtained samples are predominantly single-phase, as confirmed by X-ray diffraction and Rietveld refinement, consistent with the calculated size-disorder parameters. Multication disorder introduces substantial mass and strain-field fluctuations that promote phonon scattering. All samples exhibit p-type, thermally activated electrical transport consistent with adiabatic SPH. Sr substitution progressively reduces the hopping barrier and $ρ$, whereas non-equimolar B-site engineering partially recovers electrical transport while retaining low k. La$_{0.9}$Sr$_{0.1}$Co$_{0.4}$Cr$_{0.3}$Ni$_{0.1}$Fe$_{0.1}$Mn$_{0.1}$O$_3$, featuring a Co-rich and Cr-rich B-site composition, combines Co-associated mixed valence and spin-state degeneracy that sustain a large alpha with Cr-mediated control of carrier concentration and a reduced polaron hopping barrier of 0.19eV. This composition achieves a power factor of 40--43 $μ$W/(m K$^2$) and a $zT\sim0.072$ at 1100K, approximately 2.7 times that of its equimolar analogue. These results demonstrate that targeted cation chemistry and mass contrast, rather than configurational-entropy maximization alone, provide an effective strategy for balancing electronic and phonon transport in multicomponent oxide TE.
Comments17 Pages, 10 Figures, 3 Tables
