Electrochemical performance of the AB_5-type hydrogen storage alloy adding Co_3O_4

Effects of Co3O4 on the electrochemical performance of AB5-type hydrogen storage alloy electrode were studied by galvanostatic charge-discharge,cyclic voltammetry,linear polarization and AC impedance methods.The doped electrodes were easier to activate and a second discharge platform was observed at the voltage of 1.15 V.The maximum specific discharge capacity of electrodes with 5% and 10% Co3O4 added increased by 21.2 mAh/g and 36.0 mAh/g comparing to the blank electrode,respectively.The cycle stability of doped electrodes was fine,the capacity retain rate of electrodes with 5% and 10% Co3O4 added was 95.73% and 97.37% at the 100th cycle,respectively.The improving of electrochemical performance was caused by some Co3O4 reformed Co-Co(OH)2 reversible redox in alkaline electrolyte.Co3O4 improved the activity of electrode surface and decreased charge-transfer resistance,moderate Co3O4 addition could improve the heavy load discharge ability of alloy electrode.