【摘要】 以ZnCl₂、CoCl₂·6H₂O和草酸为原料,利用氨水为配位剂和溶液pH值调节剂,采用配位共沉淀-热分解法制备纤维状多孔钴酸锌粉末;采用X射线衍射仪、扫描电镜、透射电镜、红外光谱仪以及比表面积仪对ZnCo₂O₄粉末的形貌和结构进行了表征,考察了溶液pH值对前驱体粉末形貌和分散性的影响,并通过电化学工作站以及蓝电测试系统考察了不同热分解温度下的ZnCo₂O₄粉末作为锂离子电池负极材料的电化学性能以及钴酸锌粉末的脱嵌锂机制。结果表明:氨与锌钴离子配合生成草酸锌钴氨复盐是形成纤维状钴酸锌前驱体粉末的内在机制;热分解得到的钴酸锌粉末继承了前驱体的形貌,呈纤维状,比表面积为141 m²·g^-1,平均孔径为8. 7 nm。热分解温度为350℃时所得的钴酸锌粉末在100 mA·g^-1的电流密度下,起始比容量为1 504 mAh·g^-1,循环50次后,可逆比容量保持在987. 2 mAh·g^-1,可逆容量保持率为96. 2%;并且在500 mA·g^-1的电流密度下,其容量仍能保持在565. 7 mAh·g^-1,表明该纤维状钴酸锌粉末具有良好的循环性能和倍率性能。更多还原

【Abstract】 Porous fibrous ZnCo₂O₄ powders were synthesized by coordination precipitation-thermal decomposition method using ZnCl₂,CoCl₂·6 H₂ O and oxalic acid as raw materials,and ammonia as coordination agent and pH adjustor. The morphology and structure of ZnCo₂O₄ powders were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,infrared spectroscopy and N₂ adsorption/desorption analysis. The effect of solution pH value on the morphology of the precursor was investigated. The electrochemical properties and the litihation/de-lithiation mechanism of the as-prepared ZnCo₂O₄ powders at different decomposition temperature were also tested by CHI and LAND exam system. The results indicated that generation of ammonia-containing cobalt-zinc oxalate complex salt,which results from the coordination of ammonia with cobalt and zinc ions,is the intrinsic mechanism of the formation of precursor’s fibrous morphology. The as-prepared ZnCo₂O₄ powders inherit the morphology of the precursor with porous fibrous structure,specific surface area of 141 m²·g^-1 and average pore diameter of 8. 7 nm. These favorable characteristics contribute to satisfactory cycling performance and reasonable rating performance of the resultant ZnCo₂O₄ powders as anode materials of lithium battery. At a current density of 100 mA·g^-1,the porous fibrous ZnCo₂O₄ powders obtained at the decomposition temperature displayed delivered an initial capacity of 1 504 mAh·g^-1 and kept the reversible specific capacity of987. 2 mAh·g^-1 after 50 charge/discharge cycles with a reversible capacity retention of 96. 2%. Furthermore,the material was able to remain a capacity of 565. 7 mAh·g^-1 at a current density as high as 500 mA·g^-1.更多还原