Enhancement of thermoelectric performance of NaxCo2O4 with Ag dispersion by precipitation from Ag+ aqueous solution
Enhancement of thermoelectric performance of NaxCo2O4 with Ag dispersion by precipitation from Ag+ aqueous solution
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DOI：
10.1007/s10971-010-2261-2
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发表时间：
2010-06
影响因子：
2.5
通讯作者：
Mikio Ito;Junji Sumiyoshi
中科院分区：
文献类型：
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作者：
Mikio Ito;Junji Sumiyoshi
采用柠檬酸络合法（CAC）和Ag沉淀法在NaxCo 2 O 4粉体上制备了NaxCo 2 O 4/Ag热电复合材料。研究了合成工艺对NaxCo 2 O 4/Ag复合材料微观结构和热电性能的影响。当NaxCo 2 O 4CAC粉末浸渍在CH 3COOAg水溶液中并干燥时，在NaxCo 2 O 4粉末的表面上沉淀出尺寸小于300 nm的细小Ag颗粒。在后续烧结过程中，沿NaxCo 2 O 4晶粒间的界面沿着存在长度为5 μm、厚度为1 μm的Ag相。在这项研究中获得的Ag颗粒的尺寸被发现是小于那些常规制备的NaxCo 2 O 4/Ag复合材料。Ag颗粒的精细分散对抑制金属相Ag的加入引起的热导率的增加和提高NaxCo 2 O 4/Ag复合材料的热电性能是有效的，这表明CAC法和从CH 3COOAg水溶液中沉淀Ag的合成技术是制备NaxCo 2 O 4/Ag热电复合材料的重要工艺。
Thermoelectric NaxCo2O4/Ag composites were synthesized by citric acid complex (CAC) method and Ag precipitation from CH3COOAg aqueous solution on the NaxCo2O4powders. Effects of the synthesis process on microstructure and thermoelectric performance of NaxCo2O4/Ag composites were investigated. When the NaxCo2O4CAC powders were dipped in CH3COOAg aqueous solution and dried, fine Ag particles less than around 300 nm in size were precipitated on the surface of NaxCo2O4powders. After the subsequent sintering process, the flaky Ag phase, the length and thickness of which were up to 5 and 1 μm, respectively, existed along interfaces between NaxCo2O4grains. The sizes of Ag particles obtained in this study were found to be smaller than those of the conventionally prepared NaxCo2O4/Ag composites. The fine dispersion of Ag grains was effective for suppressing the increase in thermal conductivity due to the addition of metallic phase, Ag, and for improving the thermoelectric performance of NaxCo2O4/Ag composites, suggesting that the synthesis technique composed of the CAC method and Ag precipitation from CH3COOAg aqueous solution is significantly important process for thermoelectric NaxCo2O4/Ag composites.