Abstract Multi-walled carbon nanotubes/sodium cobalt oxide (MWCNTs/Na x CoO 2 ) composites were successfully obtained via a flame sintering method. Such sintering is accountable for a surface densification that can preserve the MWCNTs entity within the composites. Raman spectroscopy confirmed the presence of MWCNTs in the composites, with Na x CoO 2 being present as a single phase (γ) as revealed by X-ray diffraction. EDX results suggested non-uniform distribution of MWCNTs within the Na x CoO 2 material, although their presence resulted in increased electrical conductivity through enhancements in charge mobility. The effect of MWCNTs addition on the thermoelectric performance of Na x CoO 2 was examined. Addition of MWCNTs results in increased levels of phonon scattering in the composites, leading to decreased thermal conductivity. Although Seebeck coefficients decreased due to an increase in charge density, the thermoelectric efficiency of the composites reported as ZT values was enhanced in comparison to those in material without added MWCNTs, with optimum conditions found in composites derived from 0.25 wt%MWCNTs/Na x CoO 2 (with ZT enhancement by ca. 60% at 398 K).

中文翻译：

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低成本火焰烧结技术制备多壁碳纳米管/钴酸钠的热电表征

摘要 采用火焰烧结法成功制备了多壁碳纳米管/钴酸钠（MWCNTs/Na x CoO 2 ）复合材料。这种烧结是表面致密化的原因，可以在复合材料中保留 MWCNTs 实体。拉曼光谱证实复合材料中存在多壁碳纳米管，X 射线衍射显示 Na x CoO 2 以单相 (γ) 形式存在。EDX 结果表明 MWCNT 在 Na x CoO 2 材料内的分布不均匀，尽管它们的存在通过提高电荷迁移率而导致增加的电导率。研究了添加多壁碳纳米管对 Na x CoO 2 热电性能的影响。添加多壁碳纳米管会导致复合材料中声子散射水平增加，从而导致热导率降低。