La3+ was selected to elevate the lattice electronic conductivity of LiFePO4,and LiFePO4/(C+La3+) cathode powders were synthesized by microwave heating using a domestic microwave oven for 35 min. The microstructures and morphologies of the synthesized materials were investigated by XRD and SEM. The electrochemical performances were evaluated by galvanostatic charge-discharge. The electrochemical performance of LiFePO4 with different La3+ contents was studied. Results indicated that the initial specific discharge capacity of LiFePO4/(C+La3+) composites with 2% La3+ (116.3 mAh/g) was better than that of LiFePO4/C (105.4 mAh/g). The addition of La3+ further improved the electrochemical properties. So the codoping is an effective method to improve the electrochemical performance.
BaZr1-xScxO3-0.5x (x=0.07,0.10,0.13,0.16) powders were prepared by solid-state reaction method,and ZnO was used as sintering aid.Samples with different amount of ZnO additive were sintered at 1450·C for 6 h in air.Single cubic perovskite phase proton conductors were obtained.Conductivity was measured by electrochemical workstation.It was shown that Sc doping could increase conductivity through enhancing the carrier concentration in the material,but excessive Sc content might decrease the carrier concentration because of its charge compensation.ZnO had an influence on carrier concentration and mobility and affected the electrical conductivity.2 mol% ZnO and 13 mol% ScO1.5 doped sample showed the highest DC conductivity of 3.6×10-3 S·cm-1 tested at 800·C in wet hydrogen atmosphere.
Guo, Ruisong Wu, Lijun Ren, Jianxun Zhang, Jianfang Jiang, Hong
Heterogeneous composite BaZr0.1Y0.9O2.95/Na2SO4 was designed and fabricated with Y-doped BaZrO3 as matrix and Na2SO4 as dispersant by conventional powder processing to improve the total conductivity of barium zirconate. The electrical conduction of the composite was studied by electrical and electrochemical methods. Microstructure of the heterogeneous composite was examined by SEM. The experimewtal results show that the protonic conductivity of Y-doped BaZrO3 is greatly improved upon incorporating Na2SO4 in the material. Microstructure observation indicates that a multiphase structure with Na2SO4 disperses at the grain boundaries of BaZr0.1Y0.9O2.95. Electromotive force (EMF) measurements under fuel cell conditions reveal that the total ionic transport number of the composite is more than 0.9 at 750 ℃.
