Rapid synthesis of high thermoelectric performance higher manganese silicide with in-situ formed nano-phase of MnSi

P-type higher manganese silicides with in-situ formed nano-MnSi phase were prepared by a rapid melt-spinning process combined with a spark plasma sintering method (MS-SPS). Because of the in-situ formed multi-scale nano-MnSi phase, the electrical conductivity of the samples increases dramatically while the Seebeck coefficient maintains relatively high values owing possibly to an energy filtering effect. The thermal conductivity of the samples is reduced significantly with respect to that of the samples prepared by the traditional method. The MS-SPS-prepared MnSi1.75 shows a much improved ZT of 0.62 at 800 K, which represents an enhancement of 100% compared with the samples synthesized by the traditional method.

Representative nano-MnSi phase (a) and enhanced ZT value (b) of bulk MnSi1.75 materials.Figure optionsDownload as PowerPoint slideResearch highlights
► Multi-scale nano-MnSi second phase were obtaied by a melt-spinning process.
► Nano-MnSi phase increases the Seebeck coefficient and the electrical simultaneously.
► Nano-MnSi phase degreased thermal conductivity.
► The MS-SPS-prepared MnSi1.75 shows excellent TE performance and high densities.