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Tin sulfide (SnS) has analogous structural features to tin selenide (SnSe), but contains more abundant resources as compared with SnSe. SnS has elicited attention as a potential eco-friendly thermoelectric (TE) material. However, the intrinsic carrier concentration of SnS is very low, thereby hindering the performance improvement of the material. This study proposes that the TE properties of polycrystalline Nadoped SnS (synthesized through an improved chemical coprecipitation) can be significantly enhanced. The maximum power factor (PF) of 362 μW m−1K−2at 873 K was achieved, presenting a state-of-the-art value for the polycrystalline SnS. Considering the merits of the improved electrical properties and lower thermal conductivity of SnS, the highest ZTwas up to 0.52 at 873 K even without intentional chemical doping. This study offers an effective approach for improving the PF to achieve high ZTin SnS. Hence, we expect that this new perspective can be extended to other dopants and broaden the scope of synthesis technology. SnS作为一种与SnSe特征结构相似且元素丰度更高的热电材料, 受到越来越多的关注, 但是其较低的本征载流子浓度限制了热电性能的提升. 本工作利用了一种改进的化学共沉淀方法调节基体中Na+含量来提高载流子浓度, 进而提升了多晶SnS的热电性能. 最大功率因子在873 K达到362 μW m−1K−2, 高于目前关于多晶SnS的最高报道值. 得益于提升的电输运性能以及较低的热导率, ZT值在873 K达到0.52. 该工作为其他热电化合物的掺杂改性技术提供了新思路.

Cu12Sb4S13tetrahedrite has received great attention as an earth-abundant and environmental-friendly thermoelectric material. This work aims to uncover the thermoelectric performance-enhancing effect and the mechanism of nickel doping on tetrahedrite. A series of Cu12−xNixSb4S13−δ(x= 0.5, 0.7, 1.0, 1.5 and 2.0) compounds were synthesized by mechanical alloying combined with spark plasma sintering. It is found that the thermal conductivity sharply reduces with increasing Ni content over the entire temperature range, < 0.9 W m−1K−1, accompanied with an enhanced thermoelectric power factor. The model predicted that the reduced lattice thermal conductivity is attributed to mid-frequency phonon scattering, caused by precipitates and dislocations resulting from Ni doping. Consequently, a high ZTvalue up to 0.95 at 723 K was achieved for Cu11NiSb4S13−δ, corresponding to a ∼46% increase over non-doped Cu12Sb4S13−δ. Furthermore, the cyclic measurement showed that the Ni-doped tetrahedrites displayed high chemical stability. Cu12Sb4S13是一种储量丰富、 环境友好的天然矿物, 被热电领域普遍关注. 本研究旨在揭示Ni掺杂提高黝铜矿材料热电性能的机理. 采用机械合金化(MA)结合放电等离子体烧结(SPS)的方法制备出Cu12−xNixSb4S13−δ(x= 0.5, 0.7, 1.0, 1.5, 2.0)样品. 实验结果表明, 在测量温度范围内(323–723 K), 随着Ni含量的增加, 样品的热导率急剧下降(< 0.9 W m−1K−1), 同时热电功率因子逐渐增加. 理论模型计算表明, 晶格热导率的降低主要来源于Ni掺杂引起的析出相及位错对中频声子的强散射作用. 由于较低的热导率和较高的功率因子, Cu11NiSb4S13−δ样品在723 K时获得最高ZT值0.95, 相对于未掺杂样品, 其热电性能提高了46%. 同时, 热循环测试表明, 通过Ni掺杂提高了黝铜矿热电材料的化学稳定性.