The Ba-, La- and Ag-doped polycrystalline Ca2.9M0.1Co4O9 （M=Ca, Ba, La, Ag） thermoelectric bulk samples were pre- pared via citrate acid sol-gel synthesis method followed by spark plasma sintering technique. The bul...The Ba-, La- and Ag-doped polycrystalline Ca2.9M0.1Co4O9 （M=Ca, Ba, La, Ag） thermoelectric bulk samples were pre- pared via citrate acid sol-gel synthesis method followed by spark plasma sintering technique. The bulk samples were characterized and analyzed with regard to their phase compositions, grain orientations as well as microstructures. The high temperature thermoelec- tric transport properties of the bulk samples were studied in detail. All bulk samples were found to be single-phased with modified body texture. The electrical resistivity was modulated as a result of carrier concentration modification, however the carrier transport process was not influenced; the Seebeck coefficient was deteriorated simultaneously. The total thermal conductivity was remarkably reduced, on account of the decreasing of phonon thermal conductivity. The thermoelectric properties of the Ba-, La-, and Ag-doped bulk samples were optimized, and the Ba-doped Ca2.9Ba0.1Co4O9 system was found to have the highest dimensionless figure of merit ZT0.20 at 973 K, which was remarkably higher than that of the un-doped sample.展开更多
锂离子电池的性能随着正极材料、负极材料和电解液的快速发展而不断提高.过渡金属氧化物(TMs)作为有前景的负极材料,具有高理论容量和低成本的优点.由于更高的锂离子嵌入电压,过渡金属氧化物也具有更高的安全性.其中, Co3O4具有较高的...锂离子电池的性能随着正极材料、负极材料和电解液的快速发展而不断提高.过渡金属氧化物(TMs)作为有前景的负极材料,具有高理论容量和低成本的优点.由于更高的锂离子嵌入电压,过渡金属氧化物也具有更高的安全性.其中, Co3O4具有较高的可逆理论比容量(896 mA h g-1).但在充放电过程中,由于Co3O4粉化、电导率低、体积膨胀大,导致容量衰减较快和倍率性能较差[1,2].将低成本、环境友好的Ca离子取代部分Co离子可以形成C轴取向的层状氧化物Ca3Co4O9.展开更多
利用微波技术合成了Ca3Co4O9化合物,考察了微波加热时间对产物纯度和微观结构的影响;再利用微波及常规烧结技术制备了Ca3Co4O9热电陶瓷片,考察了烧结时间、烧结方式对材料微观结构和热电性能的影响.结果表明:二次微波烧结30 min制备的...利用微波技术合成了Ca3Co4O9化合物,考察了微波加热时间对产物纯度和微观结构的影响;再利用微波及常规烧结技术制备了Ca3Co4O9热电陶瓷片,考察了烧结时间、烧结方式对材料微观结构和热电性能的影响.结果表明:二次微波烧结30 min制备的热电陶瓷片在所测试温度范围内具有低电阻率、高塞贝克系数及最佳功率因子,其中966 K时微波产物的最大功率因子为0.141 m W/m K2,而常规高温烧结产物的功率因子为0.120 m W/m K2.展开更多
基金Foundation item： Project supported by National Natural Science Foundation of China （50801002）, Beijing Municipal Natural Science Foundation （2112007） and the Education Department of Henan Province Science and Technology Research Projects （13B430895）
文摘The Ba-, La- and Ag-doped polycrystalline Ca2.9M0.1Co4O9 （M=Ca, Ba, La, Ag） thermoelectric bulk samples were pre- pared via citrate acid sol-gel synthesis method followed by spark plasma sintering technique. The bulk samples were characterized and analyzed with regard to their phase compositions, grain orientations as well as microstructures. The high temperature thermoelec- tric transport properties of the bulk samples were studied in detail. All bulk samples were found to be single-phased with modified body texture. The electrical resistivity was modulated as a result of carrier concentration modification, however the carrier transport process was not influenced; the Seebeck coefficient was deteriorated simultaneously. The total thermal conductivity was remarkably reduced, on account of the decreasing of phonon thermal conductivity. The thermoelectric properties of the Ba-, La-, and Ag-doped bulk samples were optimized, and the Ba-doped Ca2.9Ba0.1Co4O9 system was found to have the highest dimensionless figure of merit ZT0.20 at 973 K, which was remarkably higher than that of the un-doped sample.
文摘锂离子电池的性能随着正极材料、负极材料和电解液的快速发展而不断提高.过渡金属氧化物(TMs)作为有前景的负极材料,具有高理论容量和低成本的优点.由于更高的锂离子嵌入电压,过渡金属氧化物也具有更高的安全性.其中, Co3O4具有较高的可逆理论比容量(896 mA h g-1).但在充放电过程中,由于Co3O4粉化、电导率低、体积膨胀大,导致容量衰减较快和倍率性能较差[1,2].将低成本、环境友好的Ca离子取代部分Co离子可以形成C轴取向的层状氧化物Ca3Co4O9.
文摘利用微波技术合成了Ca3Co4O9化合物,考察了微波加热时间对产物纯度和微观结构的影响;再利用微波及常规烧结技术制备了Ca3Co4O9热电陶瓷片,考察了烧结时间、烧结方式对材料微观结构和热电性能的影响.结果表明:二次微波烧结30 min制备的热电陶瓷片在所测试温度范围内具有低电阻率、高塞贝克系数及最佳功率因子,其中966 K时微波产物的最大功率因子为0.141 m W/m K2,而常规高温烧结产物的功率因子为0.120 m W/m K2.
