废旧锂离子动力电池中镍钴锰酸锂正极材料的回收及再利用

发布时间：2018-04-14 19:07

本文选题：废旧锂离子电池 + 回收及再利用　；参考：《郑州大学》2017年硕士论文

【摘要】：废旧锂离子动力电池中含一些有价金属元素,如:钴、镍等,和一些有毒化学物质,如:氟化物。因此,在废旧锂离子动力电池中,尤其是正极材料的回收及再利用对节约自然资源和保护环境显得非常重要。但是,就目前而言,有关废旧锂离子动力电池中镍钴锰酸锂正极材料的回收及再利用的研究比较少。针对上述问题,本文对以镍钴锰酸锂(以下简称“三元”)为正极材料的废旧锂离子动力电池的回收及再利用展开研究。本文主要研究内容包括:(1)对废旧三元锂离子动力电池进行前期的电化学性能(剩余容量、内阻、电压等)评估,并与同系列的新电池作对比。确定这些电池是否已达到无法满足在高性能电动设备中应用的废旧程度。(2)对无法满足在高性能电动设备中应用的电池,进行人工拆解回收。首先,为了确保废旧电池放电完全,拆解前通过多次对比实验,选择最佳浓度的氯化钠水溶液使电池短路并完全放电。然后,将废旧电池实施拆解,正/负极片、隔膜得到单独分离。拆解后,用有机溶剂(1-甲基-2-吡咯烷酮,简称“NMP”)将正极活性物质和集流体铝箔分离,并研究了不同的固液比、水浴温度及超声时间对正极活性物质和集流体铝箔分离的影响。随后,将回收料在不同温度下煅烧,为确定杂质碳和粘结剂(偏二氟乙烯,简称“PVDF”)等有机物质是否完全去除,通过X射线粉末晶体衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(FT-IR)、热重分析(TGA)等手段进行表征。最后,将除杂后的材料组装成纽扣电池对其进行电化学性能研究。(3)以煅烧后的三元回收料为原料,通过两种途径重新合成三元材料来提高回收料的比容量。第一种是共沉淀法,依据感应耦合等离子体(ICP)测试回收料的金属含量,采用柠檬酸作为浸取剂和络合剂来合成目标产物。并从柠檬酸浓度、过氧化氢的加入量、液料比、水浴温度以及磁力搅拌时间等5个方面对回收料的溶解率做了系列研究。第二种是高温固相法,通过在回收料中直接添加锂源经高温焙烧合成目标产物。研究了添加不同质量比锂源合成的材料,对其进行XRD、SEM等手段表征。最后,将此材料组装成纽扣电池进行充放电测试,确定出最佳的添加锂源质量比。
[Abstract]:Some valuable metal elements, such as cobalt, nickel, etc., and some toxic chemicals, such as fluoride, are found in waste lithium ion power batteries.Therefore, it is very important to save natural resources and protect the environment in the waste lithium ion power battery, especially the recovery and reuse of cathode materials.However, at present, there are few researches on the recovery and reuse of nickel cobalt manganese manganese cathode materials in waste lithium ion power batteries.In order to solve the above problems, the recovery and reuse of waste lithium ion batteries with nickel cobalt lithium manganese oxide (hereinafter referred to as "ternary") as cathode materials are studied in this paper.The main contents of this paper are as follows: (1) the electrochemical performance (residual capacity, internal resistance, voltage, etc.) of the waste lithium-ion battery is evaluated and compared with the new battery of the same series.It is determined whether these batteries have reached the level of scrap which can not be used in high performance electric equipment.) the batteries that can not be used in high performance electric equipment are manually disassembled and recovered.Firstly, in order to ensure the discharge of the waste battery is complete, the optimal concentration of sodium chloride aqueous solution is selected to make the battery short circuit and discharge completely through several comparative experiments before disassembly.Then, the waste battery is disassembled, the positive / negative plates and the diaphragm are separated separately.After disassembly, the active material of positive electrode was separated from the liquid collecting aluminum foil by using organic solvent 1 methyl 2 pyrrolidone (NMP), and the different solid-liquid ratio was studied.The effects of water bath temperature and ultrasonic time on the separation of positive active substances from liquid-collecting aluminum foil.The recycled material was then calcined at different temperatures to determine whether organic substances such as impurity carbon and binder (vinylidene fluoride, or "PVDF") were completely removed,It was characterized by X-ray powder crystal diffraction, scanning electron microscope (SEM), FT-IR, TGA and so on.Finally, the impurity removal material was assembled into a button battery to study its electrochemical performance. The calcined ternary recovery material was used as the raw material to improve the specific capacity of the recovered material through two ways.The first is the coprecipitation method. The metal content of the recovered material is measured by inductively coupled plasma ICP- (ICP). Citric acid is used as the leaching agent and the complex agent to synthesize the target product.The dissolution rate of the recovered material was studied from five aspects such as the concentration of citric acid, the amount of hydrogen peroxide, the ratio of liquid to material, the temperature of water bath and the time of magnetic stirring.The second is high temperature solid state method, which can directly add lithium source to the recycled material and calcinate the target product at high temperature.The synthetic materials with different mass ratios of lithium were studied and characterized by means of XRDX SEM.Finally, the material was assembled into a button battery for charge and discharge tests, and the optimum mass ratio of added lithium source was determined.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X705

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