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高品质六氟磷酸锂晶体的绿色制备工艺及应用
赵永锋
Thesis Advisor王跃思
2018-07
Degree Grantor中国科学院研究生院
Degree Name硕士
Degree Discipline化学工程
Keyword六氟磷酸锂,工艺设计,离子液体,超级电容器
Abstract

本论文开发了一种以氟化氢溶剂法为基础来合成电池级六氟磷酸锂的生产工艺技术,设计并完成了200吨/年工艺流程设计与计算,并根据工艺特点对关键设备进行了选型设计,完成了全工艺的流程设计,同时实现了六氟磷酸锂绿色工艺的流程开发,通过优化获得了较为理想的电池级六氟磷酸锂产品,其可减少了传统合成工艺的三废排放。具体结论如下:(1)研究了一种双釜法半间歇连续制备电池级六氟磷酸锂的绿色工艺,极大地提高了原料利用率,提高了工艺的生产效率。模型计算表明,改进氟化氢精制采出方案,采用塔顶气、液相同时采出的方法,可避免原料中的四氟化硅等轻组分进入无水氟化氢中,并获得了99.99 %的无水氟化氢产品。氟化氢精制塔的操作压力对精制操作的总能耗影响较大,操作压力越大,精制塔的操作负荷越大。(2)试验表明,不锈钢喷涂含氟化物腐蚀性能优良,喷涂PTFE或PFA塑料的复合材质,可极大地避免了不锈钢的腐蚀。对电池级六氟磷酸锂合成工艺进行了初步设计,初步完成了工艺流程验证和设备的初步设计选型,同时完成了工艺的平衡估算过程。(3)本论文通过制备的纳米复合TiO2(B)@C/rGO电极和离子液体/锂盐电解液进行匹配,获得的纳米复合超级电容器具有优异的电化学性能。本研究建立了一套新颖的高压准固态超级电容器装置。通过采用离子液体电解质和离子凝胶聚合物的复合物为隔膜,实现了高功率、高能量密度准固态杂化电容器的应用,构筑的负极材料不仅提高了电导率,而且还引入了额外的法拉第电容。制备出的TiO2(B)@C/rGO电极具有更高的比容量、更好的倍率性能和较低的内阻的特点。精确优化的准固态4 V TiO2(B)@C/rGO ASC固态杂化电容器具有49.5 Wh/kg的高能量密度和1.92 kW/kg的高功率密度。当工作温度提高到40 ℃,采用离子电解质以及离子聚合物为隔膜,最大的能量密度和功率密度达到59.4 Wh/kg和17.3 kW/kg。;LiPF6 is the most important electrolyte salt considering that new energy technologies are highly pursued to overcome the energy shortage and environment pollution issues. Note that the purity of LiPF-6 should be carefully enhanced to minmize side reactions during the electrochemistry process. This thesis was conducted to obtain a green production technology of battery-grade LiPF6 via a hydrogen fluoride solvent method. One craft process of an annual output 200 tons has been designed and optimized. Key equipments for the process have been designed and/or selected, the material balance and energy balance have been optimized to reduce the waste emissions. In addition, the application of as-obtained LiPF6 in Li-ion supercapacitor has been explored. Specific findings can be briefly summarized as follows:(1) Study of a semi batch Double pot method for continuous preparation of LiPF6 was systemically conducted to increase the efficient utilization of atoms and the production process efficiency. Our model calculation shows that improved hydrogen fluoride refining recovery scheme, adopting a method of extracted the gas and liquid at the top of the tower, can avoid the emission of light group four silicon tetrafluoride in the raw material. Therefore, anhydrous hydrofluoric acid products of 99.99 % was readily obtained. This model also indicated that hydrogen fluoride refining tower operating pressure plays a critical role on the total energy consumption of of the refining operation, and greater operating load of the refining tower was required accordingly once the operating pressure was improved.(2) The corrosion resistance of stainless steel can be enhanced greatly by being sprayed with PTFE or PFA plastics. The synthetic process of battery-grade LiPF6 was designed. In addition, process verification and key equipments selection was initially carried out to support some information for scalable production. Moreover, the equilibriums of materials and energy of the process were also estimated and optimized.(3) The application of LiPF-6 salt in new energy devices was exploited. Formulated ionic liquid/Lithium salt electrolyte and ionogel separators were prepared to achieve better performance of nano composite super-capacitor. The high power density was realized readily via both the modification of nanocarbons, which not only improve the electric conductivity but introduce extra Faradic capacitance. The as-prepared TiO2(B)@C/rGO electrode exhibits enhanced specific capacity, rate capability and lower innerresistance. Carefully optimized quasi-solid-state 4 V TiO2(B)@C/rGO ASC device shows a high energy density of 49.5 Wh/Kg at a power density of 1.92 KW/Kg. The maximum energy and power density could even reach to 59.4 Wh/kg and 17.3 kW/kg when the working temperature was increased to 40 ℃. This work provides a novel prototype for designing high-performance ASC device through formulated electrolytes as well as ionogel separators in a comprehensive compatibility mode. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/26914
Collection中国科学院过程工程研究所
研究所(批量导入)
Recommended Citation
GB/T 7714
赵永锋. 高品质六氟磷酸锂晶体的绿色制备工艺及应用[D]. 中国科学院研究生院,2018.
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