微波辅助制备不规则Co3O4花球及其电化学性能

Preparation and Electrochemical Properties of Irregular Flower-like Co3O4 Microspheres by Microwave Assisted Method

以六水合硝酸钴、苯甲酰丙酮为原料,利用微波法合成了Co3O4花球前驱体,并在500℃空气条件下锻烧得到不规则Co3O4花球。通过XRD、SEM、TEM对不规则Co3O4花球的微观结构和表面形貌进行了表征。电化学测试结果表明,不规则Co3O4花球负极材料在0.1 A/g的电流密度下,首次充电比容量达到816 m A·h/g,循环100圈后,比容量保持率为89.2%;倍率性能测试结果表明,电流密度从0.1 A/g增加到1 A/g时,比容量有一定的衰减,但电流密度恢复到0.1 A/g时,比容量几乎恢复到原来的水平;阻抗测试结果表明,不规则Co3O4花球负极材料循环前内阻为335Ω,50圈循环后内阻减小到240Ω。制备的不规则Co3O4花球具有较高的充电比容量、良好的循环性能和倍率性能。

Irregular flower-like Co3O4 microspheres were obtained by annealing the precursor at 500 ℃in air,in which the precursor was synthesized by using cobalt nitrate and benzoyl acetone as raw materials under microwave irradiation. The microstructure and morphology of sample were characterized by XRD,SEM and TEM. The as-prepared irregular flower-like Co3O4 microspheres were used as anode materials,whose charge/discharge properties and cycle performance were examined in detail. The electrochemical test results showed that the first charge specific capacity reached 816 m A · h/g at a current density of 0. 1 A/g. After 100 cycles,the specific capacity retention rate was 89. 2%.Meanwhile,the rate performance test results demonstrated that when the current density was increased from 0. 1 A/g to 1 A/g,the specific capacity exhibited a certain attenuation trend. But when the current density was restored to 0. 1 A/g,the specific capacity was almost at its original level. Electrochemical impedance spectroscopy（EIS） studies revealed that the internal resistance before circulation was 335Ω,however,it was reduced to 240 Ω after 50 cycles. All these suggested that the irregular flower-like Co3O4 microspheres had a high charge specific capacity,good cycle performance and excellent rate property.