新型铝离子电池正极材料的制备及电化学性能研究

发布时间：2018-01-24 18:30

本文关键词： 铝离子电池山峰形Ni_3S_2 第一性原理花瓣状MoS_2 绣球形CoS　出处：《青岛科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：铝离子电池由于其独特的三个电子参与氧化还原反应特性,使其具有高的理论容量,加之良好的安全特性、低的可燃性、低廉的成本,因此,其被认为是一种很有前途的新型储能器件。此外,由于过渡金属硫化物的S_2-离子和Al3+离子之间有较弱的离子键,有利于Al3+的嵌入/脱出正极材料,因此被视为铝离子电池正极材料很好的候选材料。本文通过水热法制备出系列过渡金属硫化物正极材料,优选出最佳工艺条件并对正极材料进行性能测试、表征,最后建立了性能优化机理模型,主要内容如下:(1)以泡沫Ni和硫代乙酰胺为原料,通过原位合成的方法直接在泡沫Ni基板上合成出了3D山峰形Ni_3S_2/Ni正极材料。着重研究了硫代乙酰胺浓度、反应温度及反应时间等工艺参数对电化学性能的影响规律,并通过条件实验优选出制备Ni_3S_2/Ni的工艺参数。研究结果表明,优选工艺参数为:硫代乙酰胺浓度为0.33m Mol/L、反应温度为150oC、反应时间为15h。优选工艺条件下,制备产物具有较大放电容量(236m Ah/g),较高的放电电压平台(0.7V)以及良好的循环稳定性(90次循环)。此外,基于实验和第一性原理计算,揭示了Ni_3S_2/Ni正极材料的充放电机理为Al3+嵌入/脱出Ni_3S_2正极材料形成Alx Ni_3S_2固溶体。(2)以钼酸钠和硫代乙酰胺为原料,去离子水为溶剂,采用水热法制备出具有优异电化学性能的花瓣状纳米结构Mo S_2正极材料。着重研究了反应温度、反应时间等工艺参数对产物形貌及电化学性能的影响规律,并通过条件实验优选出制备Mo S_2的工艺参数。研究结果表明,优选工艺参数为:反应温度200oC、反应时间为28小时。优选工艺条件下,制备产物的首次放电容量可以达到127.8m Ah/g,经过50次循环,电池的放电容量依然维持在44.4m Ah/g左右,库伦效率维持在110%。此外,基于电化学反应示意图和电化学反应方程式,揭示了Mo S_2正极材料的充放电机理。(3)以氯化钴为钴源,硫脲为硫源,去离子水和乙二醇为溶剂,采用水热的方法制备出具有优异电化学性能绣球形纳米结构Co S正极材料。着重研究了反应温度、反应时间等工艺参数对产物形貌及电化学性能的影响规律,并通过条件实验优选出制备Co S的工艺参数。研究结果表明,优选工艺参数为:反应温度为150oC、反应时间为15h时。优选工艺条件下,制备产物具有最大的放电容量(179.2m Ah/g),高的放电电压平台(0.55V),好的循环稳定性(50次循环)。此外,基于电化学基本原理,揭示了Co S正极材料的充放电机理。
[Abstract]:Aluminum ion batteries have high theoretical capacity, good safety, low flammability and low cost because of their unique characteristics of three electrons involved in the redox reaction. It is considered to be a promising new type of energy storage device. In addition, due to the transition metal sulfides, there is a weak ionic bond between the S _ 2- ion and the Al3 ion. It is considered as a good candidate material for aluminum ion battery cathode material because of its favorable embedding / removing cathode material of Al3. In this paper, a series of transition metal sulfide cathode materials were prepared by hydrothermal method. The optimum process conditions were selected, and the properties of the cathode materials were tested and characterized. Finally, the performance optimization mechanism model was established. The main contents are as follows: 1) the foam Ni and thioacetamide were used as raw materials. The 3D peak shape Ni_3S_2/Ni cathode material was synthesized directly on the foamed Ni substrate by in-situ synthesis. The concentration of thioacetamide was studied emphatically. The influence of reaction temperature and reaction time on the electrochemical properties of Ni_3S_2/Ni was studied. The optimum technological parameters are as follows: thioacetamide concentration is 0.33m mol / L, reaction temperature is 150oC, reaction time is 15h. The prepared product has a large discharge capacity of 236m / g, a high discharge voltage platform of 0.7V) and a good cycle stability of 90 cycles. Based on experiments and first-principles calculations. The charge-discharge mechanism of Ni_3S_2/Ni cathode materials is that Al3 intercalates / deletes Ni_3S_2 cathode materials to form Alx Ni_3S_2 solid solution. Sodium molybdate and thioacetamide were used as raw materials. The petal-like nanostructure Mo / S _ 2 cathode material with excellent electrochemical properties was prepared by hydrothermal method in deionized water. The reaction temperature was studied emphatically. The influence of reaction time and other process parameters on the morphology and electrochemical performance of the product was studied. The optimum process parameters are as follows: reaction temperature 200oC, reaction time 28h. Under the optimum conditions, the first discharge capacity of the product can reach 127.8 m Ah/g. After 50 cycles, the discharge capacity of the battery is still about 44.4 m Ah/g, and the Coulomb efficiency is 110. In addition, based on the schematic diagram of electrochemical reaction and the equation of electrochemical reaction. The charge-discharge mechanism of Mo-S2 cathode material was revealed. The cobalt chloride was used as cobalt source, thiourea as sulfur source, deionized water and ethylene glycol as solvent. Nanostructured Co S cathode materials with excellent electrochemical properties were prepared by hydrothermal method. The reaction temperature was studied emphatically. The influence of reaction time on the morphology and electrochemical performance of the product was studied. The optimum process parameters are as follows: the reaction temperature is 150oC, the reaction time is 15h, and the maximum discharge capacity of the product is 179.2m Ah路 g). In addition, the charging and discharging mechanism of Co S cathode materials is revealed based on the basic principle of electrochemistry.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;TM912

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