锂离子电池负极材料钴酸锌的制备及电化学性能研究
发布时间：2019-01-27 16:13
【摘要】：锂离子电池其有能量密度高、循环寿命长、无记忆效应等一系列优点,近年来逐渐成为新能源研究应用领域的主要研究方向之一。电极材料对锂离子电池的性能有着重要影响,其中过渡金属氧化物负极材料具有远高于碳类负极材料的理论容量而成为研究的热点。尖晶石型钴酸盐由于具有较高的放电比容量及热稳定性,低毒性、低成本等优点而备受人们关注。但其充放电过程中体积变化大、导电性差等缺点制约了其应用和进一步发展。研究表明,通过纳米化、形貌调控及元素掺杂等可有效改善上述问题,从而有效提高其电化学性能。本文以ZnCo2O4作为研究对象,以硝酸锌为锌源、硝酸钴为钴源、尿素为沉淀剂及CTAB为表面活性剂,采用溶剂热法制备前驱体,再经高温煅烧制得ZnCo2O4粉体。试验中,首先对尿素/CTAB比、加热温度、保温时间、煅烧温度等不同工艺参数用控制变量法进行对比实验,研究它们对材料结构、形貌及电化学性能的影响,在此基础上优选出最佳试验条件,所制备电池经50次循环后的放电比容量仍达261.9mAh/g。对结构中Co位原子进行了 Fe元素掺杂,研究不同掺Fe量对材料结构、形貌以及电化学性能的影响。研究表明,Fe掺杂可有效提高电池的循环稳定性,其中ZnCo1.6Fe0.4O4经50次循环后的放电比容量高达296.8mAh/g。鉴于镍基氧化物具有较高的倍率性能,本文还研究了 Ni元素掺杂的影响。对于ZnCo2-xNixO4,当x=0.2时,所制得材料具有较好的循环性能和倍率性能,在电流密度100mA/g下循环50次后的放电比容量仍能达到352mAh/g,显示出良好的应用前景。
[Abstract]:Lithium ion battery has a series of advantages such as high energy density, long cycle life, no memory effect and so on. In recent years, lithium ion battery has gradually become one of the main research directions in the field of new energy research and application. Electrode materials have an important impact on the performance of lithium ion batteries, among which transition metal oxide anode materials have much higher theoretical capacity than carbon negative electrode materials and become the focus of research. Spinel cobalt salts have attracted much attention due to their high discharge specific capacity, thermal stability, low toxicity and low cost. However, its application and further development are restricted by its large volume change and poor conductivity during charge and discharge. The results show that the above problems can be effectively improved by nanocrystalline, morphology control and element doping, and their electrochemical properties can be improved effectively. In this paper, ZnCo2O4 precursor was prepared by solvothermal method with zinc nitrate as zinc source, cobalt nitrate as cobalt source, urea as precipitant and CTAB as surfactant, and then ZnCo2O4 powder was prepared by high temperature calcination. In the experiment, the effects of urea / CTAB ratio, heating temperature, holding time and calcination temperature on the structure, morphology and electrochemical properties of the materials were studied by controlling variable method. After 50 cycles, the discharge specific capacity of the battery is still up to 261.9 mAh/ g. The Co atoms in the structure were doped with Fe elements. The effects of different Fe contents on the structure, morphology and electrochemical properties of the materials were investigated. The results show that Fe doping can effectively improve the cycle stability of the battery. The specific discharge capacity of ZnCo1.6Fe0.4O4 after 50 cycles is up to 296.8 mAh / g. In view of the high rate performance of nickel based oxides, the effect of doping of Ni elements was also studied. For ZnCo2-xNixO4, with x = 0.2, the material has good cycling performance and rate performance, and the discharge specific capacity of the material after 50 cycles at current density 100mA/g can still reach 352 mAh / g, which shows a good application prospect.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912
本文编号：2416433
[Abstract]:Lithium ion battery has a series of advantages such as high energy density, long cycle life, no memory effect and so on. In recent years, lithium ion battery has gradually become one of the main research directions in the field of new energy research and application. Electrode materials have an important impact on the performance of lithium ion batteries, among which transition metal oxide anode materials have much higher theoretical capacity than carbon negative electrode materials and become the focus of research. Spinel cobalt salts have attracted much attention due to their high discharge specific capacity, thermal stability, low toxicity and low cost. However, its application and further development are restricted by its large volume change and poor conductivity during charge and discharge. The results show that the above problems can be effectively improved by nanocrystalline, morphology control and element doping, and their electrochemical properties can be improved effectively. In this paper, ZnCo2O4 precursor was prepared by solvothermal method with zinc nitrate as zinc source, cobalt nitrate as cobalt source, urea as precipitant and CTAB as surfactant, and then ZnCo2O4 powder was prepared by high temperature calcination. In the experiment, the effects of urea / CTAB ratio, heating temperature, holding time and calcination temperature on the structure, morphology and electrochemical properties of the materials were studied by controlling variable method. After 50 cycles, the discharge specific capacity of the battery is still up to 261.9 mAh/ g. The Co atoms in the structure were doped with Fe elements. The effects of different Fe contents on the structure, morphology and electrochemical properties of the materials were investigated. The results show that Fe doping can effectively improve the cycle stability of the battery. The specific discharge capacity of ZnCo1.6Fe0.4O4 after 50 cycles is up to 296.8 mAh / g. In view of the high rate performance of nickel based oxides, the effect of doping of Ni elements was also studied. For ZnCo2-xNixO4, with x = 0.2, the material has good cycling performance and rate performance, and the discharge specific capacity of the material after 50 cycles at current density 100mA/g can still reach 352 mAh / g, which shows a good application prospect.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912
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