Modification of a first-generation solid oxide fuel cell cathode with Co3O4 nanocubes having selectively exposed crystal planes

Co 3 O 4 nanocubes with exposed (001) planes were prepared and employed for use as first-generation Sr-doped LaMnO 3 (LSM) cathodes in solid oxide fuel cells to improve the cell performance. Theoretical simulations suggest that the Co 3 O 4 (001) plane has the smallest oxygen adsorption and oxygen dissociation energies compared with other planes, thus favouring cathode reactions in solid oxide fuel cells (SOFCs). Experimental studies consistently demonstrate that a cell using an LSM cathode made with Co 3 O 4 nanocubes with selective (001) surfaces exhibits a peak power density of 500 mW cm −2 at 600 °C, while the power output for a cell using unselective (commercial) Co 3 O 4 nanoparticles is only 179 mW cm −2 at the same temperature. The electrochemical study indicates that the use of Co 3 O 4 nanoparticles with exposed (001) surfaces obviously accelerates the cathode reactions and thus decreases the polarisation resistance, which is the key to improving fuel cell performance. This study demonstrates the feasibility of using the crystal planes of metal oxides to improve the fuel cell performance and provides a new way to design SOFC cathodes.