前驱体对四氧化三钴形貌的影响与表征
来源期刊：中国有色金属学报2011年第2期
论文作者：杨幼平 张平民 刘人生 黄可龙
文章页码：442 - 449
关键词：四氧化三钴；前驱体；形貌；水热法；热分解；电化学性能
Key words：Co3O4; precursor; morphology; hydrothermal method; thermal decomposition; electrochemical performance
摘 要：以Co(CH3COO)2·4H2O为钴源，聚乙二醇(PEG)20 000为表面活性剂，在水-正丁醇溶剂体系中，分别以氢氧化钾、碳酸铵和草酸为沉淀剂，采用沉淀法制备氢氧化钴、碱式碳酸钴和草酸钴前驱体。氢氧化钴前驱体于160 ℃通过水热氧化法，可制得立方体状四氧化三钴(Co3O4)；碱式碳酸钴和草酸钴前驱体采用水热-热分解法分别于 450 ℃和400 ℃煅烧3 h可制得球链状和棒状Co3O4。用热重分析、红外光谱、X射线衍射和透射电镜对所制得前驱体和产物Co3O4的形貌和结构进行表征，并对所制备的不同形貌Co3O4进行电化学性能测试。研究结果表明：产物Co3O4的形貌与其前驱体和制备方法有关，当采用氢氧化钴前驱体可制备平均晶粒度约为15 nm的立方体状Co3O4；当采用碱式碳酸钴和草酸钴前驱体可分别制得直径约为40 nm、长约为100 nm的球链状Co3O4和直径约为0.1 μm、长度可达1 μm的棒状Co3O4。通过对不同形貌的Co3O4进行循环充放电测试，可知纳米级Co3O4的电化学性能优于微米级Co3O4的；立方体状Co3O4的电化学性能优于其他形貌Co3O4的电化学性能，其循环10次后的充电比容量为406 mA·h/g。
Abstract: The Co(OH)2, Co2(OH)2CO3 and CoC2O4 precursors were prepared by precipitation method using Co(CH3COO)2·4H2O as cobalt source, polyethylene glycol(PEG) 20 000 as surfactant, water-n-butanol as solvent system, and KOH, (NH4)2CO3 and H2C2O4·2H2O as precipitating agent, respectively. The nanocubic Co3O4 was synthesized through Co(OH)2 precursor at 160 ℃ by hydrothermal oxidation method. The catenuliform-like and rod-like Co3O4 powders were obtained when Co2(OH)2CO3 and CoC2O4 precursors were calcined at 450 ℃ and 400 ℃ for 3 h by hydrothermal-thermal decomposition method, respectively. The morphology and structure of precursor and Co3O4 product were characterized by thermogravimetry(TG), infrared(IR) spectrum, X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The electrochemical performance of as-prepared Co3O4 with different morphologies was tested. The results show that the morphologies of Co3O4 change with the precursors prepared using different precipitating agents and methods. The cubic Co3O4 with particle size of 15 nm can be obtained using Co(OH)2 as precursor, and catenuliform-like Co3O4 with about 40 nm in diameter and 100 nm in length and rod-like Co3O4 with about 0.1 μm in diameter and 1 μm in length can be obtained using Co2(OH)2CO3 and CoC2O4 as precursors, respectively. The electrochemical performance of nano-Co3O4 is superior to that of micro-Co3O4. The cubic Co3O4 shows the best electrochemical performance in all the as-prepared Co3O4 samples, and its specific charge capacity retains 406 mA·h/g after 10 discharge-charge cycles.
基金信息：国家自然科学基金资助项目
