技术领域Technical field
本发明属于锂电池资源回收技术领域，尤其涉及一种电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法。The invention belongs to the technical field of lithium battery resource recovery, and in particular relates to a method for electrochemical yin and yang coupling wet recovery of decommissioned lithium iron phosphate batteries.
背景技术Background technique
目前，全球正面临着环境污染和能源危机的加剧问题。因此，全球能源转型升级、碳减排要求不断提高，促进世界各国加快了新能源汽车产业发展的步伐。研究预计在2025年前后，普通燃油汽车将全面被新能源汽车所替代(销量将仅占乘用车总销量的50％左右)，而纯电动汽车、混合动力汽车和生物燃料汽车等新能源汽车成为未来汽车行业的发展方向。Currently, the world is facing the intensification of environmental pollution and energy crisis. Therefore, global energy transformation and upgrading and carbon emission reduction requirements continue to increase, prompting countries around the world to accelerate the pace of development of the new energy vehicle industry. Research predicts that around 2025, ordinary fuel vehicles will be completely replaced by new energy vehicles (sales will only account for about 50% of total passenger vehicle sales), while new energy vehicles such as pure electric vehicles, hybrid vehicles, and biofuel vehicles Become the future development direction of the automotive industry.
锂离子型动力电池是新能源汽车的关键部件，其中磷酸铁锂(LiFePO4)电池凭借优异的循环性能和安全性能，在大型乘用车(电动大巴、公交车等)领域已经得到了广泛应用。然而，经过长期循环过程中锂的大量损耗和电化学副反应，以及电极表面结构的非晶态转变和氧耗，导致磷酸铁锂电池容量衰减并最终失效报废，其使用寿命通常为4-8年。近几年进入了磷酸铁锂电池规模化退役阶段，每年将有超过100万吨废旧锂离子电池。退役磷酸铁锂电池含有大量锂、铁、镍和钴等有色金属资源，若不能妥善处置，不仅将带来锂资源浪费，而且其电解液中的含氟组分等会给环境带来潜在威胁。此外，随着碳酸锂价格不断攀升，回收退役磷酸铁锂电池的经济效益逐渐凸显，新兴的回收退役磷酸铁锂电池的技术和工艺陆续涌现。Lithium-ion power batteries are key components of new energy vehicles. Among them, lithium iron phosphate (LiFePO4 ) batteries have been widely used in the field of large passenger vehicles (electric buses, buses, etc.) due to their excellent cycle performance and safety performance. . However, after long-term cycling, the massive loss of lithium and electrochemical side reactions, as well as the amorphous transformation of the electrode surface structure and oxygen consumption, lead to capacity attenuation of lithium iron phosphate batteries and eventually failure and scrapping. Their service life is usually 4-8 Year. In recent years, we have entered the stage of large-scale decommissioning of lithium iron phosphate batteries, and there will be more than 1 million tons of waste lithium-ion batteries every year. Retired lithium iron phosphate batteries contain a large amount of non-ferrous metal resources such as lithium, iron, nickel and cobalt. If not properly disposed of, not only will there be a waste of lithium resources, but the fluorine-containing components in the electrolyte will also pose potential threats to the environment. . In addition, as the price of lithium carbonate continues to rise, the economic benefits of recycling retired lithium iron phosphate batteries have gradually become more prominent, and emerging technologies and processes for recycling retired lithium iron phosphate batteries have emerged one after another.
目前，退役磷酸铁锂电池处理工艺主要分为和火法冶金和湿法浸出。其中，火法冶金处理流程长，容易造成Li结渣，导致有价金属的综合回收率较低。湿法浸出通过浸出、除杂、富集过程使退役磷酸铁锂中的有价金属进入溶液并进行回收，具有金属回收率和除杂效率高、技术适应性强的优点。FeLiPO4具有稳定性较高的橄榄石结构，且失效的磷酸铁锂材料上的导电剂、黏结剂和石墨包覆层也会严重阻碍其分解。为实现锂元素的充分提取，湿法浸出工艺需要通过强酸浸出剂(如HCl、H2SO4、H3PO4等无机强酸)以及氧化剂(H2O2)的辅助破坏其化学结构。当前，在梯级回收退役磷酸铁锂电池中有价金属过程中，往往会使用络合剂和萃取剂，提高回收渣相的金属纯度。因此，湿法浸出存在回收过程复杂、节约化学品用量/能源消耗之间的失衡等缺点，增加工艺安环的成本，无法高效和绿色回收退役磷酸铁锂电池。At present, the treatment processes for decommissioned lithium iron phosphate batteries are mainly divided into pyrometallurgy and wet leaching. Among them, the pyrometallurgical treatment process is long and can easily cause slag formation, resulting in a low comprehensive recovery rate of valuable metals. Wet leaching allows valuable metals in decommissioned lithium iron phosphate to enter the solution and be recovered through the process of leaching, impurity removal, and enrichment. It has the advantages of high metal recovery rate, high impurity removal efficiency, and strong technical adaptability. FeLiPO4 has a highly stable olivine structure, and the conductive agent, binder and graphite coating layer on the failed lithium iron phosphate material will also seriously hinder its decomposition. In order to fully extract lithium, the wet leaching process requires the assistance of strong acid leaching agents (such as HCl, H2 SO4 , H3 PO4 and other inorganic strong acids) and oxidants (H2 O2 ) to destroy its chemical structure. Currently, in the process of cascade recovery of valuable metals in decommissioned lithium iron phosphate batteries, complexing agents and extractants are often used to improve the metal purity of the recovered slag phase. Therefore, wet leaching has the disadvantages of complex recycling process, imbalance between chemical consumption/energy consumption, increased process safety and environmental costs, and cannot efficiently and greenly recycle retired lithium iron phosphate batteries.
如：专利CN 116750746A通过使用大量氧化剂、还原剂和络合剂，实现磷、铁、锂的全组分回收。然而，未反应的酸或还原剂/氧化剂，最终都会进入流出物中，增加废液量，并造成二次污染。专利CN 102897804 A通过反应-萃取耦合法，以二氧化碳为碳源得到纯度较高的碳酸锂，加入有机萃取剂，打破热力学限制，促使反应向生成碳酸锂产物方向进行。这种方法需要对萃取剂进行油水相分离和反萃再生，工艺流程复杂，增加能耗和成本。专利CN115947353 A通过电解含Cl-电解液，生成氯气，并于水反应生成HCl、HClO和HClO3，进而促进磷酸铁锂废料的氧化分解，使得锂浸出。该方法对设备具有很强的腐蚀性，造成处理成本和维护成本升高。For example: Patent CN 116750746A achieves full component recovery of phosphorus, iron and lithium by using a large amount of oxidants, reducing agents and complexing agents. However, unreacted acid or reducing/oxidizing agents will eventually enter the effluent, increasing the amount of waste liquid and causing secondary pollution. Patent CN 102897804 A uses carbon dioxide as the carbon source to obtain higher-purity lithium carbonate through a reaction-extraction coupling method. An organic extractant is added to break the thermodynamic limitations and promote the reaction to generate lithium carbonate products. This method requires oil-water phase separation and stripping regeneration of the extraction agent, which complicates the process and increases energy consumption and cost. Patent CN115947353 A generates chlorine gas through electrolysis of Cl- containing electrolyte, and reacts with water to generate HCl, HClO and HClO3 , thereby promoting the oxidative decomposition of lithium iron phosphate waste and causing lithium leaching. This method is highly corrosive to the equipment, resulting in higher disposal and maintenance costs.
因此，针对现有退役磷酸铁锂电池的湿法回收过程中存在的各种问题，需要开发一种新的方式以实现退役磷酸铁锂电池的高效回收。Therefore, in view of various problems existing in the wet recycling process of retired lithium iron phosphate batteries, a new method needs to be developed to achieve efficient recycling of retired lithium iron phosphate batteries.
发明内容Contents of the invention
为解决上述技术问题，本发明提供了一种电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法，通过电解实现对退役磷酸铁锂电池的氧化分解，无需添加任何辅助剂，在阳极上Fe2+离子直接氧化为Fe3+，促进磷酸铁锂的解离过程；同时在阴极上定向双电子ORR产生的H2O2与磷酸铁锂反应生产磷酸铁和·OH，而·OH的自催化效应会进一步促进磷酸铁锂的定向活化解构，该方法具有工艺条件温和、成本低、无二次污染等优点。In order to solve the above technical problems, the present invention provides an electrochemical anode-coupled wet method for recycling retired lithium iron phosphate batteries. The oxidative decomposition of retired lithium iron phosphate batteries is achieved through electrolysis without adding any auxiliary agent. Fe on the anode isThe 2+ ions are directly oxidized to Fe3+ to promote the dissociation process of lithium iron phosphate; at the same time, the H2 O2 generated by the directional two-electron ORR on the cathode reacts with the lithium iron phosphate to produce iron phosphate and ·OH, and the self-dissociation of ·OH The catalytic effect will further promote the directional activation and deconstruction of lithium iron phosphate. This method has the advantages of mild process conditions, low cost, and no secondary pollution.
本发明的目的是提供一种电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法，包括以下步骤，The object of the invention is to provide a method for electrochemical yin-positive coupling wet recycling of decommissioned lithium iron phosphate batteries, which includes the following steps:
S1、对退役磷酸铁锂电池进行预处理，得到磷酸铁锂废料；S1. Preprocess retired lithium iron phosphate batteries to obtain lithium iron phosphate waste;
S2、采用包括工作电极、对电极和参比电极的电化学体系对电解液进行电解，在阴阳电极上的电子直接氧化和间接氧化作用下，所述磷酸铁锂废料被氧化分解，得到含磷酸铁和Li+的混合液；所述电解液中包括浓度为0.01mol/L-0.2mol/L的酸溶液；所述电解液中还包括S1所述的磷酸铁锂废料；S2. Use an electrochemical system including a working electrode, a counter electrode and a reference electrode to electrolyze the electrolyte. Under the direct oxidation and indirect oxidation of electrons on the anode and anode electrodes, the lithium iron phosphate waste is oxidized and decomposed to obtain phosphoric acid. A mixed solution of iron and Li+ ; the electrolyte includes an acid solution with a concentration of 0.01 mol/L-0.2 mol/L; the electrolyte also includes the lithium iron phosphate waste described in S1;
S3、对S2所述的含磷酸铁和Li+的混合液进行过滤处理，得到磷酸铁和含Li+滤液；S3. Filter the mixed liquid containing iron phosphate and Li+ described in S2 to obtain iron phosphate and Li+ -containing filtrate;
S4、向S3所述的含Li+滤液中通入二氧化碳进行沉锂反应，反应结束后进行过滤处理，得到碳酸锂。S4. Pass carbon dioxide into the Li+ -containing filtrate described in S3 to perform a lithium precipitation reaction. After the reaction is completed, filter the solution to obtain lithium carbonate.
在本发明的一个实施例中，在S1中，所述预处理是对退役磷酸铁锂电池进行放电、拆解、破碎、筛分、材料区分。In one embodiment of the present invention, in S1, the pretreatment includes discharging, dismantling, crushing, screening, and material differentiation of retired lithium iron phosphate batteries.
在本发明的一个实施例中，在S1中，所述酸溶液的浓度优选为0.02mol/L、0.04mol/L、0.06mol/L、0.08mol/L、0.1mol/L、0.12mol/L、0.14mol/L、0.16mol/L、0.18mol/L。In one embodiment of the present invention, in S1, the concentration of the acid solution is preferably 0.02mol/L, 0.04mol/L, 0.06mol/L, 0.08mol/L, 0.1mol/L, 0.12mol/L , 0.14mol/L, 0.16mol/L, 0.18mol/L.
在本发明的一个实施例中，在S1中，所述磷酸铁锂废料中铁的质量占比为30％-40％，锂的质量占比为2％-6％。In one embodiment of the present invention, in S1, the mass proportion of iron in the lithium iron phosphate waste is 30%-40%, and the mass proportion of lithium is 2%-6%.
在本发明的一个实施例中，在S2中，所述工作电极和对电极为活化石墨烯气凝胶GA电极；所述参比电极为Ag/AgCl电极。In one embodiment of the present invention, in S2, the working electrode and the counter electrode are activated graphene aerogel GA electrodes; the reference electrode is an Ag/AgCl electrode.
在本发明的一个实施例中，所述活化石墨烯气凝胶GA电极以活化石墨烯气凝胶GA作为电极材料，以泡沫镍作为电极基底；所述活化石墨烯气凝胶GA是由石墨烯气凝胶GA经HNO3煮沸和N2焙烧制备得到。In one embodiment of the present invention, the activated graphene airgel GA electrode uses activated graphene airgel GA as the electrode material and nickel foam as the electrode base; the activated graphene airgel GA is made of graphite The olefin aerogel GA was prepared by HNO3 boiling and N2 roasting.
在本发明的一个实施例中，所述HNO3煮沸的煮沸时间为5min-30min；所述N2焙烧的焙烧温度为360℃-540℃。In one embodiment of the present invention, the boiling time of HNO3 boiling is 5min-30min; the roasting temperature ofN2 roasting is 360°C-540°C.
进一步地，所述HNO3煮沸的煮沸时间为10min-20min，如11min、12min、13min、14min、15min、16min、17min、18min、19min；所述N2焙烧的焙烧温度为400℃-500℃，如410℃、420℃、430℃、440℃、450℃、460℃、470℃。Further, the boiling time of the HNO3 boiling is 10min-20min, such as 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min; the roasting temperature of theN2 roasting is 400℃-500℃, Such as 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃.
在本发明的一个实施例中，所述活化石墨烯气凝胶GA电极的制备具体包括以下步骤：In one embodiment of the present invention, the preparation of the activated graphene airgel GA electrode specifically includes the following steps:
S21、将石墨烯气凝胶GA溶于HNO3中，经行煮沸、洗涤；S21. Dissolve the graphene airgel GA in HNO3 , boil and wash;
S22、N2氛围下，对经S21洗涤后的石墨烯气凝胶GA进行焙烧，得到活化石墨烯气凝胶GA；Under S22 and N2 atmosphere, the graphene aerogel GA washed with S21 is roasted to obtain activated graphene aerogel GA;
S23、将S2所述的活化石墨烯气凝胶GA通过物理方法压片附着在泡沫镍上，形成所述的活化石墨烯气凝胶GA电极。S23. Press the activated graphene airgel GA described in S2 and attach it to the nickel foam through physical methods to form the activated graphene airgel GA electrode.
在本发明的一个实施例中，在S2中，所述电解的条件为：电极电位为0V-5V，电解时间为0.75h-5h。In one embodiment of the present invention, in S2, the electrolysis conditions are: the electrode potential is 0V-5V, and the electrolysis time is 0.75h-5h.
进一步地，在S2中，所述电解的条件为：电极电位为0.1V-2V，电解时间为0.75h-3h。Further, in S2, the electrolysis conditions are: the electrode potential is 0.1V-2V, and the electrolysis time is 0.75h-3h.
优选地，在S2中，所述电解的条件为：电极电位为0.3V-1V，如0.4V、0.5V、0.6V、0.7V、0.8V、0.9V；电解时间为0.75h-2h，如1h、1.25h、1.5h、1.75h。Preferably, in S2, the electrolysis conditions are: the electrode potential is 0.3V-1V, such as 0.4V, 0.5V, 0.6V, 0.7V, 0.8V, 0.9V; the electrolysis time is 0.75h-2h, such as 1h, 1.25h, 1.5h, 1.75h.
在本发明的一个实施例中，在S2中，所述电解液和所述磷酸铁锂废料的质量比为4.5-10：1。In one embodiment of the present invention, in S2, the mass ratio of the electrolyte and the lithium iron phosphate waste is 4.5-10:1.
进一步地，在S2中，所述电解液和所述磷酸铁锂废料的质量比为4.5-8：1。Further, in S2, the mass ratio of the electrolyte and the lithium iron phosphate waste is 4.5-8:1.
优选地，在S2中，所述电解液和所述磷酸铁锂废料的质量比为4.5-6：1，如(5：1)、(5.5：1)。Preferably, in S2, the mass ratio of the electrolyte and the lithium iron phosphate waste is 4.5-6:1, such as (5:1), (5.5:1).
在本发明的一个实施例中，在S2中，所述酸选自硫酸、磷酸、甲酸、乙酸、草酸和柠檬酸中的一种或多种。In one embodiment of the present invention, in S2, the acid is selected from one or more of sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid and citric acid.
在本发明的一个实施例中，在S2中，所述氧化分解的原理如下：In one embodiment of the present invention, in S2, the principle of the oxidative decomposition is as follows:
阳极上发生反应如下：The reaction at the anode is as follows:
Fe2+-e-→Fe3+Fe2+ -e- → Fe3+
即，在直接氧化作用下，磷酸铁锂废料被氧化解离。That is, under direct oxidation, lithium iron phosphate waste is oxidized and dissociated.
阴极上发生反应如下：The reaction at the cathode is as follows:
O2+2H++2e-→H2O2O2 +2H+ +2e- →H2 O2
H2O2+Fe2+→Fe3++OH-+·OHH2 O2 +Fe2+ →Fe3+ +OH- +·OH
Fe2++·OH→Fe3++OH-Fe2+ +·OH→Fe3+ +OH-
即，在阴极上具有两种间接氧化作用，阴极上定向双电子ORR产生的H2O2对磷酸铁锂废料粉末具有间接氧化作用，反应生成磷酸铁和·OH，而·OH的自催化效应会进一步促进磷酸铁锂废料的定向活化解构。That is, there are two indirect oxidations on the cathode. The H2 O2 generated by the directional two-electron ORR on the cathode has an indirect oxidation effect on the lithium iron phosphate waste powder, and the reaction generates iron phosphate and ·OH, and the autocatalytic effect of ·OH It will further promote the directional activation and deconstruction of lithium iron phosphate waste.
在本发明的一个实施例中，在S4中，所述沉锂反应的温度为10℃-100℃，时间为0.1h-5h。In one embodiment of the present invention, in S4, the temperature of the lithium precipitation reaction is 10°C-100°C, and the time is 0.1h-5h.
进一步地，在S4中，所述沉锂反应的温度为20℃-90℃，时间为0.3h-3h。Further, in S4, the temperature of the lithium precipitation reaction is 20°C-90°C, and the time is 0.3h-3h.
优选地，在S4中，所述沉锂反应的温度为30℃-60℃，如35℃、40℃、45℃、50℃、55℃；时间为0.5h-2h，如0.75h、1h、1.25h、1.5h、1.75h。Preferably, in S4, the temperature of the lithium precipitation reaction is 30°C-60°C, such as 35°C, 40°C, 45°C, 50°C, 55°C; the time is 0.5h-2h, such as 0.75h, 1h, 1.25h, 1.5h, 1.75h.
在本发明的一个实施例中，回收的磷酸铁和碳酸锂可再应用于锂离子电池。In one embodiment of the present invention, the recycled iron phosphate and lithium carbonate can be reused in lithium-ion batteries.
本发明的技术方案相比现有技术具有以下优点：The technical solution of the present invention has the following advantages compared with the existing technology:
(1)本发明所述的方法通过电解低浓介质，实现对磷酸铁锂电池的氧化分解。整个过程无需消耗电解液，无需消耗过量的酸和碱以中和溶液，减少废液排放，无二次污染，显著降低成本。另外，酸浓度较低的电解液有利于磷酸铁沉淀的形成，减少溶液中Fe3+离子含量，提高后续回收锂产品的纯度。(1) The method of the present invention achieves oxidative decomposition of lithium iron phosphate batteries by electrolyzing low-concentration media. The entire process does not require the consumption of electrolyte or excessive acid and alkali to neutralize the solution, reducing waste liquid discharge, no secondary pollution, and significantly reducing costs. In addition, electrolytes with lower acid concentrations are conducive to the formation of iron phosphate precipitation, reducing the Fe3+ ion content in the solution and improving the purity of subsequent recovered lithium products.
(2)本发明所述的方法无需添加任何辅助剂，如O2、Cl2、H2O2等等，减少运输和储存成本，降低对设备的要求，简化工艺流程，操作简单，无二次污染且可连续生产等优点。(2) The method of the present invention does not require the addition of any auxiliary agents, such as O2 , Cl2 , H2 O2 , etc., which reduces transportation and storage costs, lowers requirements for equipment, simplifies the process flow, and is simple to operate. It has the advantages of less pollution and continuous production.
(3)本发明所述的方法可以用连续、长周期生产，能够带来更好的环境和经济效益，具有良好的应用前景。(3) The method of the present invention can be used for continuous and long-term production, can bring better environmental and economic benefits, and has good application prospects.
附图说明Description of the drawings
为了使本发明的内容更容易被清楚地理解，下面根据本发明的具体实施例并结合附图，对本发明作进一步详细的说明，其中：In order to make the content of the present invention easier to understand clearly, the present invention will be further described in detail below based on specific embodiments of the present invention and in conjunction with the accompanying drawings, wherein:
图1为本发明电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法的工艺流程图；Figure 1 is a process flow chart of the method for recycling decommissioned lithium iron phosphate batteries by electrochemical yin and yang coupling wet method according to the present invention;
图2为本发明电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法的原理示意图；Figure 2 is a schematic diagram of the principle of the method of electrochemical yin-positive coupling wet recycling of decommissioned lithium iron phosphate batteries according to the present invention;
图3为本发明实施例的活化石墨烯气凝胶GA的表征图；其中，a为SEM图像，b为拉曼光谱图；Figure 3 is a characterization diagram of the activated graphene airgel GA according to the embodiment of the present invention; a is a SEM image, and b is a Raman spectrum;
图4为本发明工作电极的电性能测试图；其中，a为电子自旋共振(ESR)光谱，b为恒流充放电曲线，c为长周期循环曲线。Figure 4 is an electrical performance test chart of the working electrode of the present invention; where a is the electron spin resonance (ESR) spectrum, b is the constant current charge and discharge curve, and c is the long-period cycle curve.
具体实施方式Detailed ways
下面结合附图和具体实施例对本发明作进一步说明，以使本领域的技术人员可以更好地理解本发明并能予以实施，但所举实施例不作为对本发明的限定。The present invention will be further described below in conjunction with the accompanying drawings and specific examples, so that those skilled in the art can better understand and implement the present invention, but the examples are not intended to limit the present invention.
在本发明中，除非另有说明，实施例中预处理是对退役磷酸铁锂电池进行放电、拆解、破碎、筛分等，将隔膜、黏接剂、铝箔等材料分开处理。In the present invention, unless otherwise stated, the pretreatment in the embodiment includes discharging, dismantling, crushing, screening, etc. of retired lithium iron phosphate batteries, and separately processing separators, adhesives, aluminum foil and other materials.
在本发明中，除非另有说明，实施例中采用的活化石墨烯气凝胶GA电极的制备具体包括以下步骤：(1)将100mg石墨烯气凝胶GA在4mL HNO3中煮沸15min，然后用超纯水多次洗涤；(2)在N2氛围下的管式炉中，经洗涤后的石墨烯气凝胶GA于450℃焙烧1h，得到活化石墨烯气凝胶GA；(3)将活化石墨烯气凝胶GA通过物理方法压片附着在泡沫镍上，形成活化石墨烯气凝胶GA电极，干燥备用。In the present invention, unless otherwise stated, the preparation of the activated graphene aerogel GA electrode used in the examples specifically includes the following steps: (1) Boil 100 mg graphene aerogel GA in 4 mL HNO3 for 15 min, and then Wash multiple times with ultrapure water; (2) In a tube furnace underN2 atmosphere, the washed graphene aerogel GA is roasted at 450°C for 1 hour to obtain activated graphene aerogel GA; (3) The activated graphene airgel GA is pressed onto the nickel foam through physical methods to form an activated graphene airgel GA electrode, which is dried and ready for use.
实施例1Example 1
参照图1所示，本发明的电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法，具体包括以下步骤：Referring to Figure 1, the electrochemical anode-coupled wet method of recycling retired lithium iron phosphate batteries of the present invention specifically includes the following steps:
S1、退役磷酸铁锂电池经过预处理，得到Fe的质量占比约35％，Li的质量占比4.4％的磷酸铁锂废料粉末；S1. The retired lithium iron phosphate battery is preprocessed to obtain lithium iron phosphate waste powder with a mass proportion of Fe of about 35% and a mass proportion of Li of 4.4%;
S2、以0.1M H2SO4溶液为电解液，以活化石墨烯气凝胶GA电极作为工作电极/对电极(阴阳电极)，以Ag/AgCl电极作为参比电极，并且接入CHI760E电化学工作站，控制电极电位为0.6V，电解时间为1h，进行碳酸铁锂废料的电化学氧化分解，得到含磷酸铁和Li+的混合液；其中，电解液中还包括磷酸铁锂废料，电解液和磷酸铁锂废料的质量比为5：1；S2. Use 0.1MH2 SO4 solution as the electrolyte, use the activated graphene airgel GA electrode as the working electrode/counter electrode (anode and cathode), use the Ag/AgCl electrode as the reference electrode, and connect to the CHI760E electrochemical workstation , control the electrode potential to 0.6V, and the electrolysis time to 1 hour, conduct electrochemical oxidation and decomposition of lithium iron carbonate waste, and obtain a mixed solution containing iron phosphate and Li+ ; among which, the electrolyte also includes lithium iron phosphate waste, electrolyte and The mass ratio of lithium iron phosphate waste is 5:1;
S3、待电解结束后，对含磷酸铁和Li+的混合液进行过滤，然后使用水洗涤两次，在100℃烘箱中干燥2h，得到磷酸铁和含Li+滤液；S3. After the electrolysis is completed, filter the mixture containing iron phosphate and Li+ , then wash it twice with water, and dry it in an oven at 100°C for 2 hours to obtain the filtrate containing iron phosphate and Li+ ;
S4、向含Li+滤液中通入二氧化碳进行沉锂反应，其中反应温度为40℃，反应时间1h，待Li+沉淀反应完毕后过滤处理，然后使用水洗涤两次，在80℃真空干燥箱中干燥4h，得到碳酸锂沉淀。S4. Pour carbon dioxide into the filtrate containing Li+ to perform lithium precipitation reaction, where the reaction temperature is 40°C and the reaction time is 1 hour. After the Li+ precipitation reaction is completed, filter it, then wash it twice with water, and dry it in a vacuum drying oven at 80°C. Dry for 4 hours to obtain lithium carbonate precipitate.
经检测，本实施例中退役磷酸铁锂电池中Li+的浸出率(电解后电解液中Li元素质量/电解前磷酸铁锂废料粉末中Li元素质量×100％)为99.55％，本实施例中碳酸锂沉淀中铁元素原子占比为0.076％，其电解原理如图2所示。After testing, the leaching rate of Li+ in the decommissioned lithium iron phosphate battery in this example (mass of Li element in the electrolyte after electrolysis/mass of Li element in the lithium iron phosphate waste powder before electrolysis × 100%) is 99.55%. The proportion of iron atoms in the lithium carbonate precipitation is 0.076%. The electrolysis principle is shown in Figure 2.
实施例2Example 2
本发明的电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法，具体包括以下步骤：The electrochemical anode-coupled wet method for recycling retired lithium iron phosphate batteries of the present invention specifically includes the following steps:
S1、退役磷酸铁锂电池经过预处理，得到Fe的质量占比约35％，Li的质量占比4.4％的磷酸铁锂废料粉末；S1. The retired lithium iron phosphate battery is preprocessed to obtain lithium iron phosphate waste powder with a mass proportion of Fe of about 35% and a mass proportion of Li of 4.4%;
S2、以0.1M H3PO4溶液为电解液，以活化石墨烯气凝胶GA电极作为工作电极/对电极(阴阳电极)，以Ag/AgCl电极作为参比电极，并且接入CHI760E电化学工作站，控制电极电位为0.6V，电解时间为1h，进行碳酸铁里废料的电化学氧化分解，得到含磷酸铁和Li+的混合液；其中，电解液中还包括磷酸铁锂废料，电解液和磷酸铁锂废料的质量比为5：1；S2. Use 0.1MH3 PO4 solution as the electrolyte, use the activated graphene airgel GA electrode as the working electrode/counter electrode (anode and cathode), use the Ag/AgCl electrode as the reference electrode, and connect to the CHI760E electrochemical workstation , control the electrode potential to 0.6V, and the electrolysis time to 1 hour, perform electrochemical oxidation and decomposition of the waste in iron carbonate, and obtain a mixed solution containing iron phosphate and Li+ ; among which, the electrolyte also includes lithium iron phosphate waste, electrolyte and The mass ratio of lithium iron phosphate waste is 5:1;
S3、待电解结束后，对含磷酸铁和Li+的混合液进行过滤，然后使用水洗涤两次，在100℃烘箱中干燥2h，得到磷酸铁和含Li+滤液；S3. After the electrolysis is completed, filter the mixture containing iron phosphate and Li+ , then wash it twice with water, and dry it in an oven at 100°C for 2 hours to obtain the filtrate containing iron phosphate and Li+ ;
S4、向含Li+滤液中通入二氧化碳进行沉锂反应，其中反应温度为40℃，反应时间1h，待Li+沉淀反应完毕后过滤处理，然后使用水洗涤两次，在80℃真空干燥箱中干燥4h，得到碳酸锂沉淀。S4. Pour carbon dioxide into the filtrate containing Li+ to perform lithium precipitation reaction, where the reaction temperature is 40°C and the reaction time is 1 hour. After the Li+ precipitation reaction is completed, filter it, then wash it twice with water, and dry it in a vacuum drying oven at 80°C. Dry for 4 hours to obtain lithium carbonate precipitate.
经检测，本实施例中退役磷酸铁锂电池中Li+的浸出率为99.18％，本实施例中碳酸锂沉淀中铁元素原子占比为0.051％。After testing, the leaching rate of Li+ in the retired lithium iron phosphate battery in this example is 99.18%, and the proportion of iron atoms in the lithium carbonate precipitation in this example is 0.051%.
实施例3Example 3
本发明的电化学阴阳耦合湿法回收退役磷酸铁锂电池的方法，具体包括以下步骤：The electrochemical anode-coupled wet method for recycling retired lithium iron phosphate batteries of the present invention specifically includes the following steps:
S1、退役磷酸铁锂电池经过预处理，得到Fe的质量占比约35％，Li的质量占比4.4％的磷酸铁锂废料粉末；S1. The retired lithium iron phosphate battery is preprocessed to obtain lithium iron phosphate waste powder with a mass proportion of Fe of about 35% and a mass proportion of Li of 4.4%;
S2、以0.1M乙酸溶液为电解液，以活化石墨烯气凝胶GA电极作为工作电极/对电极(阴阳电极)，以Ag/AgCl电极作为参比电极，并且接入CHI760E电化学工作站，控制电极电位为0.6V，电解时间为1h，进行碳酸铁里废料的电化学氧化分解，得到含磷酸铁和Li+的混合液；其中，电解液中还包括磷酸铁锂废料，电解液和磷酸铁锂废料的质量比为5：1；S2. Use 0.1M acetic acid solution as the electrolyte, use the activated graphene airgel GA electrode as the working electrode/counter electrode (anode and cathode), use the Ag/AgCl electrode as the reference electrode, and connect to the CHI760E electrochemical workstation to control The electrode potential is 0.6V and the electrolysis time is 1 hour. Electrochemical oxidation and decomposition of the waste in iron carbonate is carried out to obtain a mixed solution containing iron phosphate and Li+ ; among which, the electrolyte also includes lithium iron phosphate waste, electrolyte and iron phosphate The mass ratio of lithium waste is 5:1;
S3、待电解结束后，对含磷酸铁和Li+的混合液进行过滤，然后使用水洗涤两次，在100℃烘箱中干燥2h，得到磷酸铁和含Li+滤液；S3. After the electrolysis is completed, filter the mixture containing iron phosphate and Li+ , then wash it twice with water, and dry it in an oven at 100°C for 2 hours to obtain the filtrate containing iron phosphate and Li+ ;
S4、向含Li+滤液中通入二氧化碳进行沉锂反应，其中反应温度为40℃，反应时间1h，待Li+沉淀反应完毕后过滤处理，然后使用水洗涤两次，在80℃真空干燥箱中干燥4h，得到碳酸锂沉淀。S4. Pour carbon dioxide into the filtrate containing Li+ to perform lithium precipitation reaction, where the reaction temperature is 40°C and the reaction time is 1 hour. After the Li+ precipitation reaction is completed, filter it, then wash it twice with water, and dry it in a vacuum drying oven at 80°C. Dry for 4 hours to obtain lithium carbonate precipitate.
经检测，本实施例中退役磷酸铁锂电池中Li+的浸出率为99.04％，本实施例中碳酸锂沉淀中铁元素原子占比为0.088％。After testing, the leaching rate of Li+ in the retired lithium iron phosphate battery in this example is 99.04%, and the proportion of iron atoms in the lithium carbonate precipitation in this example is 0.088%.
对比例1Comparative example 1
基本同实施例1，不同之处在于：活化石墨烯气凝胶GA电极的焙烧温度为350℃。It is basically the same as Example 1, except that the baking temperature of the activated graphene airgel GA electrode is 350°C.
经检测，本对比例中退役磷酸铁锂电池中Li+的浸出率为94.37％，本实施例中碳酸锂沉淀产品中铁元素原子占比为0.824％。After testing, the leaching rate of Li+ in the retired lithium iron phosphate battery in this comparative example is 94.37%. In this example, the proportion of iron atoms in the lithium carbonate precipitation product is 0.824%.
对比例2Comparative example 2
基本同实施例1，不同之处在于：活化石墨烯气凝胶GA电极焙烧550℃。It is basically the same as Example 1, except that the activated graphene airgel GA electrode is baked at 550°C.
经检测，本对比例中退役磷酸铁锂电池中Li+的浸出率为96.33％，本实施例中碳酸锂沉淀产品中铁元素原子占比为0.501％。After testing, the leaching rate of Li+ in the retired lithium iron phosphate battery in this comparative example is 96.33%. In this example, the proportion of iron atoms in the lithium carbonate precipitation product is 0.501%.
对比例3Comparative example 3
基本同实施例1，不同之处在于：电解液和磷酸铁锂废料的质量比为4：1。It is basically the same as Example 1, except that the mass ratio of electrolyte and lithium iron phosphate waste is 4:1.
经检测，本对比例中退役磷酸铁锂电池中Li+的浸出率为97.16％，本实施例中碳酸锂沉淀产品中铁元素原子占比为0.182％。After testing, the leaching rate of Li+ in the retired lithium iron phosphate battery in this comparative example is 97.16%. In this example, the proportion of iron atoms in the lithium carbonate precipitation product is 0.182%.
对比例4Comparative example 4
基本同实施例1，不同之处在于：电解时间为0.5h。It is basically the same as Example 1, except that the electrolysis time is 0.5h.
经检测，本对比例中退役磷酸铁锂电池中Li+的浸出率为85.64％，本实施例中碳酸锂沉淀产品中铁元素原子占比为1.557％。After testing, the leaching rate of Li+ in the decommissioned lithium iron phosphate battery in this comparative example is 85.64%, and the proportion of iron atoms in the lithium carbonate precipitation product in this example is 1.557%.
测试例1Test example 1
对实施例中采用的活化石墨烯气凝胶GA电极的表面形貌进行了表征，结果如图3所示。从图3a的扫描电镜图可以看出，GA是由石墨烯薄片组成的高多孔结构，其比表面积为143.2m2/g，平均孔直径为3.5nm。从图3b的拉曼光谱图可以看出，活化石墨烯气凝胶GA电极材料在1358cm-1和1591cm-1处的两个清晰峰分别对应于无序碳的D带和石墨碳的G带，其ID/IG值分别为0.98，表明存在高活性的缺陷位点。结果表明，活化石墨烯气凝胶GA优异的电子、结构和催化性能可以增强ORR的质量传递和电催化性能。The surface morphology of the activated graphene airgel GA electrode used in the example was characterized, and the results are shown in Figure 3. It can be seen from the scanning electron microscope image in Figure 3a that GA is a highly porous structure composed of graphene flakes, with a specific surface area of 143.2m2 /g and an average pore diameter of 3.5nm. It can be seen from the Raman spectrum in Figure 3b that the two clear peaks of the activated graphene airgel GA electrode material at 1358cm-1 and 1591cm-1 respectively correspond to the D band of disordered carbon and the G band of graphitic carbon. , whose ID/IG values are 0.98 respectively, indicating the existence of highly active defect sites. The results show that the excellent electronic, structural and catalytic properties of activated graphene aerogel GA can enhance the mass transfer and electrocatalytic performance of ORR.
测试例2Test example 2
基于实施例1，对工作电极进行电性能测试，电子自旋共振(ESR)谱图如图4a所示。从图4a可以看出，活化石墨烯气凝胶GA电极具有较强的ESR强度，表明活化石墨烯气凝胶GA的氧空位浓度较高，有利于电极定向双电子自选共振的氧化还原反应。在电流密度为0.2A/g条件下进行了恒流充放电(GCD)试验，以确定活化石墨烯气凝胶GA电极材料的电容，如图4b所示。从图4b可以看出，在0.2A/g时的放电时间较大，且具有良好的电容。在5A/g电流密度条件下，活化石墨烯气凝胶GA电极的长周期循环曲线，如图4c所示。从图4c可以看出，活化石墨烯气凝胶GA电极具有优越的充电放电性能和良好的10,000次循环的循环稳定性。结果表明，活化石墨烯气凝胶GA电极材料具有优异的稳定性并且可以重复利用。Based on Example 1, the electrical properties of the working electrode were tested, and the electron spin resonance (ESR) spectrum is shown in Figure 4a. As can be seen from Figure 4a, the activated graphene airgel GA electrode has strong ESR intensity, indicating that the oxygen vacancy concentration of the activated graphene airgel GA is high, which is conducive to the redox reaction of the electrode's directional two-electron self-selected resonance. A constant current charge and discharge (GCD) test was conducted at a current density of 0.2A/g to determine the capacitance of the activated graphene airgel GA electrode material, as shown in Figure 4b. As can be seen from Figure 4b, the discharge time at 0.2A/g is larger and has good capacitance. The long-period cycle curve of the activated graphene airgel GA electrode under the current density of 5A/g is shown in Figure 4c. As can be seen from Figure 4c, the activated graphene airgel GA electrode has superior charge-discharge performance and good cycle stability for 10,000 cycles. The results show that the activated graphene airgel GA electrode material has excellent stability and can be reused.
显然，上述实施例仅仅是为清楚地说明所作的举例，并非对实施方式的限定。对于所属领域的普通技术人员来说，在上述说明的基础上还可以做出其它不同形式变化或变动。这里无需也无法对所有的实施方式予以穷举。而由此所引申出的显而易见的变化或变动仍处于本发明创造的保护范围之中。Obviously, the above-mentioned embodiments are only examples for clear explanation and are not intended to limit the implementation. For those of ordinary skill in the art, other changes or modifications may be made based on the above description. An exhaustive list of all implementations is neither necessary nor possible. The obvious changes or modifications derived therefrom are still within the protection scope of the present invention.
| Application Number | Priority Date | Filing Date | Title |
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| CN202311450093.3ACN117383588A (en) | 2023-11-02 | 2023-11-02 | An electrochemical yin and yang coupled wet method for recycling retired lithium iron phosphate batteries |
| PCT/CN2023/132496WO2025091578A1 (en) | 2023-11-02 | 2023-11-20 | Method for recovering spent lithium iron phosphate battery by using electrochemical cathode and anode coupling wet process |
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| CN202311450093.3ACN117383588A (en) | 2023-11-02 | 2023-11-02 | An electrochemical yin and yang coupled wet method for recycling retired lithium iron phosphate batteries |
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| WO (1) | WO2025091578A1 (en) |
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| CN119240758A (en)* | 2024-12-04 | 2025-01-03 | 中蓝长化工程科技有限公司 | A method for simultaneously recovering retired lithium iron phosphate and ternary lithium battery black powder |
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