Preparation And Characterization Of Lithiated Ni-based Cathode

Solid oxide fuel cell (SOFC) is a kind of efficient energy conversiondevice which converts chemical energy to electrical power directly.However, it is difficult to commercialize traditional SOFCsoperating at high temperature due to the strict demands forelectrode materials and related technologies. Naturally, SOFCsoperating at intermediate temperature becomes a trend for laterresearch and thus synthesizing novel cathode materials withexcellent electrocatalytic performance and high stability atintermediate temperature is of necessity.In this work, nickel-based mixed transition-metal oxideNi0.79Co0.2Zn0.01O（NCZ）has been prepared with EDTA-Citriccombined complexing method and on the basis ofaforementioned NCZ, lithiated NCZ cathode Li0.2Ni0.79Co0.2Zn0.01O2（LNCZ） has been synthesized successfully by solid statereaction method. The results from room-temperature XRD showthat both NCZ and LNCZ are single phase with the same structure. Moreover, output characteristics and polarizationdegrees of the cells Ni-Ce0.8Sm0.2O1.9∣SDC∣SDC-NCZ andNi-Ce0.8Sm0.2O1.9∣SDC∣SDC-LNCZ have been tested by I-V、I-Pand impedance measurements and the results reveal that LNCZowns higher electrochemical performance and lowerpolarization resistance under the same conditions. Themaximum power density of the single cell Ni-Ce0.8Sm0.2O1.9∣SDC∣SDC-LNCZ achieves1459mW/cm2、1146mW/cm2、764mW/cm2、440mW/cm2and polarization resistances of the cell are0.004Ωcm2、0.024Ωcm2、0.109Ωcm2、0.357Ωcm2at700℃,650℃,600℃,550℃, respectively, better than the cell Ni-Ce0.8Sm0.2O1.9∣SDC∣SDC-NCZ with the maximum power densities898mW/cm2、584m W/c m2、326mW/cm2、150mW/cm2a n d p o l a r i z a t i o nresistances0.049Ωcm2、0.124Ωcm2、0.292Ωcm2、0.811Ωcm2atcorresponding temperatures. Thus, Lithiated NCZ oxide,possessing excellent electrochemical capability, is a desiredcathode for IT-SOFCs.Then, we have synthesized nickel-based oxide Ni1/3Co1/3Mn1/3Oδ（NCM）and Lithiated NCM cathode Ni1/3Co1/3Mn1/3O2（LNCM）usingmethods above and from XRD we know that LiNi1/3Co1/3Mn1/3O2possesses layered structure. More research has been made for NCMand LNCM about their electrochemical and polarization degrees and it is found LNCM owns better electrochemical performance thanNCM. For the single cell Ni-Ce0.8Sm0.2O1.9∣SDC∣SDC-LNCM, themaximum power densities782mW/cm2、450mW/cm2、245mW/cm2、117mW/cm2and polarization resistances0.042Ωcm2、0.114Ωcm2、0.331Ωcm2、0.961Ωcm2have been attained at700℃,650℃,600℃,550℃, respectively, indicating lithiated NCM is a promising butundesired cathode for IT-SOFCs and worth further improvement.