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
Ca3CO4O9 （CCO） and Ca2.95K0.05Co4O9 （CKCO） powders have been prepared by the polyacrylamide gel method. CKCO shows increased capacity and better cycling stability compared with CCO. After cycled for 50 cycles at 0...Ca3CO4O9 （CCO） and Ca2.95K0.05Co4O9 （CKCO） powders have been prepared by the polyacrylamide gel method. CKCO shows increased capacity and better cycling stability compared with CCO. After cycled for 50 cycles at 0.5 C, CKCO retains a capacity of 223 mAh.g-1, almost twice than CCO. The electrochemical impedance spectroscopy （EIS） tests shows the CKCO sample has a lower initial charge transfer resistance （Rot） and undergoes smaller Rot change during cycling than the CCO sample, indicating improved electrochemical performance by K-doping.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Ca3CO4O9 （CCO） and Ca2.95K0.05Co4O9 （CKCO） powders have been prepared by the polyacrylamide gel method. CKCO shows increased capacity and better cycling stability compared with CCO. After cycled for 50 cycles at 0.5 C, CKCO retains a capacity of 223 mAh.g-1, almost twice than CCO. The electrochemical impedance spectroscopy （EIS） tests shows the CKCO sample has a lower initial charge transfer resistance （Rot） and undergoes smaller Rot change during cycling than the CCO sample, indicating improved electrochemical performance by K-doping.
