废旧磷酸盐类及混合锂离子电池回收再利用研究

发布时间：2018-07-03 13:07

本文选题：废旧锂离子电池 + 磷酸盐正极材料　；参考：《哈尔滨工业大学》2017年博士论文

【摘要】：锂离子电池广泛应用于各种消费类电子产品和电动汽车领域,导致锂和钴等金属的资源需求量迅速增加,探索合理的回收方法,实现对废旧锂离子电池回收及再利用是缓解资源紧张,消除环境污染的有效方法。目前,人们对废旧钴酸锂电池的回收研究较多,而针对磷酸盐类以及各类混合锂离子电池的回收再利用研究还很少。基于此,本论文针对废旧磷酸亚铁锂,磷酸钒锂以及各种类型混合锂离子电池进行回收,探讨废旧锂离子电池中活性物质与集流体的分离机制,建立针对不同类型锂离子电池的分离方法;优化金属离子的回收工艺,使用同步辐射X射线吸收和扫描电镜等手段研究回收产品的物理化学性能;实现回收产品再制备电极材料,考察再制备材料的物理性能及电化学性能。探讨废旧锂离子电池中活性物质与集流体的分离方法,对于废旧磷酸盐类锂离子电池,采用600℃热处理1 h,分解粘结剂实现活性物质与集流体的分离,同时将Fe2+氧化为Fe3+,利于后续磷酸铁的回收利用;整体回收混合废旧锂离子电池,采用碱溶液溶解铝箔实现活性物质与集流体的分离,最佳的反应条件氢氧化钠的浓度为30 g·L-1,温度为50℃,时间为1 h;回收废旧锂离子电池正极片采用0.5 mol·L-1氢氧化钠溶液溶解微量的铝箔,造成活性物质与集流体接触界面缺陷,在超声辅助下分离活性物质与集流体,并探讨了超声辅助的分离机制。研究废旧锂离子电池中金属离子的回收方法,将废旧磷酸亚铁锂电池分离得到的活性物质溶于硫酸中实现铁和锂的浸出,最佳浸出条件为:硫酸浓度为2.5 mol?L-1,液固比为10 m L?g-1,温度为60℃,时间为4 h,铁和锂的浸出率分别98%和97%。使用氨水调整p H值为2,沉淀磷酸铁,探讨了表面活性剂对回收产品的粒度及表面形貌的影响,结果表明加入非离子型表面活性剂回收的产品粒径较小且粒度分布更为均匀,同步辐射X射线吸收测试结果显示,加入非离子型表面活性剂回收的产品与商品化磷酸铁中铁元素具有相同的局域结构。LiFePO4和Li3V2(PO4)3材料的特征相近,制备方法类似,研究从废旧LiFePO4和Li3V2(PO4)3混合锂离子电池中回收Li、Fe和V,再制备x LiFePO4-y Li3V2(PO4)3的方法。通过热处理分离活性物质与集流体分离后,调节活性物质中Li、Fe、V和P摩尔比,经球磨、锻烧,制备不同比例的x LiFePO4-y Li3V2(PO4)3(x:y=5:1,7:1,9:1)复合电极材料,其结果对于磷酸钒锂电池回收再利用新工艺路线的研发有指导作用。将混合废旧锂离子电池(包括Li Co O2、Li Mn2O4、Li NixCoy Mnz O2和LiFePO4)分离活性物质与集流体后,硫酸与过氧化氢的混合物浸出活性物质中的金属离子,为了保证回收产品的纯度,进行了杂质去除研究,采用沉淀法去除铁离子,铜萃取剂去除铜离子,磷酸酯类萃取剂进一步去除铁、铝和铜等其它杂质,氢氧化钠共沉淀镍钴锰避免了金属离子的分离提纯,直接制备三元锂离子电池前驱体。研究回收产品的再利用,以优化条件下回收获得的磷酸铁和碳酸锂为原料,碳热还原法再制备Li FePO4/C。采用XAFS对再制备的LiFePO4/C与商品化产品进行对比发现,加入非离子表面活性剂回收产品再制备的LiFePO4/C与商品化产品最为接近。将优化条件下再制备LiFePO4/C为正极材料,组装成半电池后,首次充放电容量分别为155.4 m Ah?g-1和153.3 m Ah?g-1,表现出与商品化的产品相类似的电化学性能。废旧LiFePO4和Li3V2(PO4)3混合回收再制备的x LiFePO4-y Li3V2(PO4)3复合材料与纯化学试剂制备的复合材料有相似的电化学性能,解决了废旧Li3V2(PO4)3电池难于回收的现状,为废旧锂离子电池资源化回收探索了新的途径。以废旧混合锂离子电池回收的前驱体和碳酸锂为原料,固相法再制备Li(Ni1/3Co1/3Mn1/3)O2,组装成的半电池后,首次放电容量为148.8 m Ah?g-1,100次循环效率为97%,再制备的产品与纯化学试剂制备的样本进行对比,两者具有相似的物理性能和电化学性能,并形成了可实施的磷酸铁锂电池、磷酸钒锂电池以及各种混合锂离子电池回收再利用的工艺技术。
[Abstract]:Lithium ion batteries are widely used in all kinds of consumer electronics and electric vehicles, leading to a rapid increase in resource demand for lithium and cobalt metals. To explore a reasonable recovery method and to realize recycling and reuse of waste lithium ion batteries is an effective method to relieve resources and eliminate environmental pollution. There are many researches on the recovery of batteries, and the recovery and reuse of various kinds of phosphates and various kinds of hybrid lithium ion batteries are very few. Based on this, this paper deals with the recycling of waste lithium phosphate, lithium phosphate and various types of mixed lithium ion batteries, and discusses the separation mechanism of the active substances and the fluid collection in the waste lithium ion battery. The separation method for different types of lithium ion batteries was established, the recovery process of metal ions was optimized, the physical and chemical properties of the recycled products were studied by means of synchrotron radiation X ray absorption and scanning electron microscopy. The physical and electrochemical properties of the recycled products were realized, and the waste lithium was studied. The separation method of the active substance and the collector in the subbattery is used for the waste phosphate lithium ion battery. The heat treatment of the waste phosphate lithium-ion battery is 1 h at 600 C. The separation of the active substance from the fluid is decomposed by the decomposition of the binder. At the same time, the Fe2+ is oxidized to Fe3+, which is beneficial to the recovery and utilization of the subsequent iron phosphate; the whole waste lithium ion battery is recovered and dissolved in the alkali solution. The aluminum foil can separate the active material from the concentrated fluid. The optimum reaction condition is that the concentration of sodium hydroxide is 30 g. L-1, the temperature is 50 C and the time is 1 h. The recycled waste lithium ion battery positive electrode dissolves the trace aluminum foil with 0.5 mol. L-1 sodium hydroxide solution, resulting in the contact interface defect of the active material and the fluid collector. The recovery method of metal ions in waste lithium ion batteries was studied. The recovery method of metal ions in waste lithium ion batteries was studied. The leaching of iron and lithium was achieved by dissolving the active substance separated from the waste lithium phosphate lithium battery in sulfuric acid. The optimum leaching condition was as follows: the concentration of sulfuric acid was 2.5 mol? L-1, the liquid to solid ratio was 10 m L? G-1, and the temperature was 6 The leaching rate of iron and lithium was 4 h, the leaching rate of iron and lithium was 98% and 97%. using ammonia water to adjust P H value to 2 and precipitate iron phosphate. The effect of surface active agent on the grain size and surface morphology of the recycled products was discussed. The results showed that the particle size of the products recovered by the addition of non ionic surfactants was smaller and the particle size distribution was more uniform, and the X ray absorption of synchrotron radiation was obtained. The test results show that the products recovered from non ionic surfactants are similar to the local structure.LiFePO4 and Li3V2 (PO4) 3 materials in the commercialized iron phosphate, and the preparation method is similar. The recovery of Li, Fe and V from the waste LiFePO4 and Li3V2 (PO4) 3 lithium ion batteries was studied, and x LiFePO4-y Li3V2 (3) was prepared. By separating the active substances from the fluid by heat treatment and adjusting the molar ratio of Li, Fe, V and P in the active substances, the X LiFePO4-y Li3V2 (PO4) 3 (x:y=5:1,7:1,9:1) composite electrode materials with different proportions are prepared by ball milling and forging. The results have a guiding role for the research and development of the new process route for recycling and reuse of the lithium vanadium lithium battery. After separating active substances from waste lithium ion batteries (including Li Co O2, Li Mn2O4, Li NixCoy Mnz O2 and LiFePO4), the metal ions in the active substances are leached from the mixture of sulfuric acid and hydrogen peroxide. In order to ensure the purity of the recycled products, the impurity removal is studied. The iron ions are removed by precipitation method and copper extractant is used to remove the copper ionization. The phosphate extractants further remove the other impurities such as iron, aluminum and copper, and the co precipitation of Ni, CO and Mn by sodium hydroxide to avoid the separation and purification of metal ions. The precursor of three yuan lithium ion battery is prepared directly. The reutilization of the recycled products is studied. The recovery of iron phosphate and lithium carbonate obtained under the optimized conditions is used as the raw material, and the carbon thermo reduction method is used to prepare the L I FePO4/C. uses XAFS to compare the reproduced LiFePO4/C and commercialized products, and it is found that the LiFePO4/C which is prepared by adding non-ionic surfactants is the closest to the commercialized product. The initial charge and discharge capacity is 155.4 m Ah, g-1 and 153, respectively, after the preparation of LiFePO4/C as positive material under the optimized condition. .3 m Ah? G-1 shows electrochemical properties similar to that of commercialized products. Waste LiFePO4 and Li3V2 (PO4) 3 mixed recovery and recycled x LiFePO4-y Li3V2 (PO4) 3 composite has similar electrochemical properties with pure chemical reagents. It solves the current status of waste recycling 3 batteries, which is used for waste lithium ion electricity. A new way is explored for the recycling of pool resources. Using the precursors and lithium carbonate recycled by waste lithium ion batteries as raw materials, Li (Ni1/3Co1/3Mn1/3) O2 is prepared by solid phase method, and the first discharge capacity is 148.8 m Ah? G-1100 secondary circulation efficiency of 97% after solid phase preparation, and the products prepared are compared with the samples prepared by pure chemical reagents. Both of them have similar physical and electrochemical properties, and have formed an enforceable technology for reusing lithium iron phosphate battery, lithium phosphate battery and all kinds of lithium ion batteries.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X705

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