Investigation of Mn Single and Co-Doping in Thermoelectric CoSb<sub>3</sub>-Skutterudite: A Way Toward a Beneficial Composite Effect
Cédric Bourgès, Wenhao Zhang, Krushna Kumari Raut, Yuka Owada, Naoyuki Kawamoto, Masanori Mitome, Kazuaki Kobayashi, Jean‐François Halet, David Berthebaud, Takao Mori
Abstract
High Resolution Image Download MS PowerPoint Slide We report here the first in-depth theoretical and experimental investigations of Mn substitution within the CoSb 3 -skutterudite. A systematic and comprehensive approach was employed to first determine the feasibility of single/cosubstitution for Mn with Te and then assess its effect. Subsequently, experimental realization of the samples was conducted. We were able to highlight a low solubility limit of Mn as a single dopant and provide evidence that the substitution stabilizes p -type conduction, as predicted via density functional theory calculations. Then, we reveal the prevalent formation of the composite MnTe/CoSb 3 -skutterudite phases instead of the expected favorable cosubstitution. This unexpected composite formation induces a beneficial effect, maximizing the Seebeck coefficient and leading to a record power factor (PF) of ≈ 4.7 mW/m K 2 at 725 K for an unfilled skutterudite compound (PF = S 2 σ with S, Seebeck coefficient; σ, electrical conductivity).