溶液法制备电池级四氟硼酸锂及电化学性能研究
发布时间：2018-08-28 08:16
【摘要】：随着经济的快速发展,环境污染、能源短缺已成为每个人都不得不面对的问题。锂离子电池因其具有比能量高、循环寿命长、无记忆效应、安全环保等优点,吸引了能源、交通、环境、航天等各方面的广泛关注。电解质是锂离子电池一个不可或缺的组成部分,性能优良的电解质是锂离子电池获得高电压、高能量密度等优点的保证。四氟硼酸锂(LiBF_4)作为锂离子电池的电解质具有热稳定性好、对水分相对不敏感、毒性小、安全性高、能有效防止A1集电极的腐蚀、制备成本低等优点,是锂离子电池电解液中的重要组成,有较好的市场前景。本文采用溶液法,以氢氟酸、硼酸和碳酸锂为原料制备电池级电解质LiBF_4。利用IR、XRD、AAS、ICP-AES及DTA等对四氟硼酸锂产物进行了表征,通过电池测试系统及电化学工作站对产物四氟硼酸锂的电化学性能进行测试。本文主要研究内容有以下几个方面:(1)以氢氟酸、硼酸和碳酸锂为原料,溶液法制备电池级四氟硼酸锂产品,考查了反应温度、原料的摩尔比、蒸发量、结晶温度等因素对四氟硼酸锂产品产率及纯度的影响。通过单因素实验及正交实验得到最佳工艺条件为反应温度7.5℃、原料摩尔比n(氢氟酸):n(硼酸):n(碳酸锂)为4.05:1.00:0.56、乙醇蒸发量占溶剂量的65%、结晶温度15℃。在此条件下得到四氟硼酸锂纯度为99.22%(原子吸收法测得),产品产率90.08%。(2)利用红外光谱对自制的产物进行结构分析、X射线衍射法对产物进行定性分析,证明自制产品中得到目标产物LiBF_4。利用原子吸收法测定目标产物LiBF_4的锂离子,利用ICP-AES测定产物中的锂离子及其他金属杂质离子,利用重量法(沉淀重量法和滴定重量法)对样品中的氟硼酸根进行测定,上述三种纯度分析结果表明最佳条件下样品纯度很高,高达99.00%以上。利用热分析对四氟硼酸锂进行表征,其在DTA图谱中290～300℃处有吸热峰,说明目标产物LiBF_4有良好的热稳定性。(3)将自制LiBF_4配制成电解液并制成纽扣电池,利用电池测试系统及电化学工作站对其进行电化学性能测定,证明其具有高充放电电压及良好的循环性能。实验表明溶液法制备电池级LiBF_4工艺可行。该工艺反应条件温和,副产物为水和二氧化碳易除去,产品纯度高,溶剂循环利用,解决了传统方法中一直采用腐蚀性、强毒性的试剂等致命缺点。
[Abstract]:With the rapid development of economy and environmental pollution, energy shortage has become a problem that everyone has to face. Li-ion battery has attracted wide attention in energy, transportation, environment and aerospace due to its advantages such as high specific energy, long cycle life, no memory effect, safety and environmental protection. Electrolyte is an indispensable part of lithium-ion battery, and the excellent electrolyte is the guarantee of obtaining high voltage and high energy density of lithium-ion battery. Lithium tetrafluoroborate (LiBF_4) as an electrolyte for lithium-ion batteries has the advantages of good thermal stability, relatively insensitive to water, low toxicity, high safety, and can effectively prevent corrosion of A1 collector and lower preparation cost. It is an important component of lithium ion battery electrolyte and has a good market prospect. In this paper, battery-grade electrolyte LiBF_4. was prepared from hydrofluoric acid, boric acid and lithium carbonate by solution method. The products of lithium tetrafluoroborate were characterized by IR,XRD,AAS,ICP-AES and DTA. The electrochemical properties of lithium tetrafluoroborate were tested by battery test system and electrochemical workstation. The main contents of this paper are as follows: (1) the battery grade lithium tetrafluoroborate was prepared by solution method using hydrofluoric acid, boric acid and lithium carbonate as raw materials. The reaction temperature, molar ratio of raw materials and evaporation were investigated. Effect of crystallization temperature on the yield and purity of lithium tetrafluoroborate. By single factor experiment and orthogonal experiment, the optimum conditions are as follows: reaction temperature 7.5 鈩，
本文编号：2208816
[Abstract]:With the rapid development of economy and environmental pollution, energy shortage has become a problem that everyone has to face. Li-ion battery has attracted wide attention in energy, transportation, environment and aerospace due to its advantages such as high specific energy, long cycle life, no memory effect, safety and environmental protection. Electrolyte is an indispensable part of lithium-ion battery, and the excellent electrolyte is the guarantee of obtaining high voltage and high energy density of lithium-ion battery. Lithium tetrafluoroborate (LiBF_4) as an electrolyte for lithium-ion batteries has the advantages of good thermal stability, relatively insensitive to water, low toxicity, high safety, and can effectively prevent corrosion of A1 collector and lower preparation cost. It is an important component of lithium ion battery electrolyte and has a good market prospect. In this paper, battery-grade electrolyte LiBF_4. was prepared from hydrofluoric acid, boric acid and lithium carbonate by solution method. The products of lithium tetrafluoroborate were characterized by IR,XRD,AAS,ICP-AES and DTA. The electrochemical properties of lithium tetrafluoroborate were tested by battery test system and electrochemical workstation. The main contents of this paper are as follows: (1) the battery grade lithium tetrafluoroborate was prepared by solution method using hydrofluoric acid, boric acid and lithium carbonate as raw materials. The reaction temperature, molar ratio of raw materials and evaporation were investigated. Effect of crystallization temperature on the yield and purity of lithium tetrafluoroborate. By single factor experiment and orthogonal experiment, the optimum conditions are as follows: reaction temperature 7.5 鈩，
本文编号：2208816
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