WO2013166929A1

WO2013166929A1 - Graphene composite material for negative electrode of lithium-ion battery and preparation method thereof

Info

Publication number: WO2013166929A1
Application number: PCT/CN2013/074995
Authority: WO
Inventors: 丁兆龙; 王振中
Original assignee: 常州第六元素材料科技股份有限公司
Priority date: 2012-05-11
Filing date: 2013-04-28
Publication date: 2013-11-14
Also published as: CN102683657B; CN102683657A

Abstract

The invention relates to a graphene composite material for a negative electrode of a lithium-ion battery and a preparation method thereof, which belong to the technical field of electrodes preparation of the lithium-ion battery. The preparation method of the graphene composite material for the negative electrode of the lithium-ion battery comprises the steps of: oxidizing a graphene material in a concentrated acid environment; mixing the obtained graphene material with a titanium source after ultrasonic dispersion; drying and calcining to obtain the graphene composite material. The graphene composite material for the negative electrode of the lithium-ion battery, provided by the invention, has high conductivity. The obtained electrode has low resistance and good structural stability in a charge/discharge cycle. The prepared lithium-ion secondary battery has the advantages of high capacity, high safety, excellent cycle performance and long-term durability.

Description

一种锂离子电池负极用石墨烯复合材料及其制备方法 Graphene composite material for negative electrode of lithium ion battery and preparation method thereof

技术领域 Technical field

本发明涉及一种锂离子电池负极用复合材料及其制备方法，进一步地，涉及一种锂离子电池负极用的石墨烯复合材料及其制备方法，属于锂离子电池电极制备技术领域。 The invention relates to a composite material for a lithium ion battery negative electrode and a preparation method thereof, and further relates to a graphene composite material for a lithium ion battery negative electrode and a preparation method thereof, and belongs to the technical field of lithium ion battery electrode preparation.

背景技术 Background technique

锂离子电池由于能量密度高，循环性能好等优点，自其商业化以来已经得到了广泛的应用。特别是随着混合动力汽车和电动汽车行业的迅速发展，锂离子电池作为其中的重要储能装置受到了越来越多的重视。锂离子电池负极是电池的重要组成部分，它的结构与性能直接影响锂离子电池的容量和循环性能。目前商用的锂离子电池负极材料以石墨为主，但是其容量较低（理论容量仅为 Lithium-ion batteries have been widely used since their commercialization due to their high energy density and good cycle performance. Especially with the rapid development of the hybrid vehicle and electric vehicle industry, lithium ion batteries have received more and more attention as important energy storage devices. The negative electrode of lithium-ion battery is an important part of the battery, and its structure and performance directly affect the capacity and cycle performance of the lithium-ion battery. Currently, commercial lithium-ion battery anode materials are mainly graphite, but their capacity is low (the theoretical capacity is only

372mAh/g), 在需要高能量输出的领域的应用受到限制。金属氧化物如 Ti0₂、 Sn0₂等作为锂离子电池负极材料具有很高的比容量，然而这些金属氧化物存在离子扩散率低、在电极中的电子传输性差、高倍率放电时界面电阻高、容量衰减迅速等缺陷，限制了金属氧化物作为锂离子电池负极材料的发展和应用。 372 mAh/g) is limited in applications where high energy output is required. Metal oxides such as Ti0 ₂ and SnO ₂ have high specific capacity as negative electrode materials for lithium ion batteries. However, these metal oxides have low ion diffusivity, poor electron transport in electrodes, and high interface resistance at high rate discharge. Defects such as rapid capacity decay limit the development and application of metal oxides as anode materials for lithium ion batteries.

为了提高锂离子电池的充放电速率，一种有效的方法是使金属氧化物与导电添加剂结合形成混合纳米结构，例如与常规碳添加剂（Super-P或乙炔黑）结合，或与碳纳米管（CNT) 结合，或与 Ru0₂结合。尽管这些复合材料取得了显著的效果，但一些用于提高比表面的材料（如 R_U0₂和CNT)本身是昂贵的，而且需要很高的含量（例如 20%或更高）来确保在电极中的电子传输性。为了提高金属氧化物高倍率放电性能并降低成本，需要一种能够与金属氧化物以纳米尺寸结合的具有高比表面积和高导电性的材料。 In order to increase the charge and discharge rate of a lithium ion battery, an effective method is to combine a metal oxide with a conductive additive to form a hybrid nanostructure, such as a conventional carbon additive (Super-P or acetylene black), or with a carbon nanotube ( CNT) binds, or binds to Ru0 ₂ . Although these composites have achieved significant results, some materials used to increase the specific surface (such as R _U 0 ₂ and CNT) are inherently expensive and require high levels (eg 20% or higher) to ensure Electron transportability in the electrode. In order to improve the high rate discharge performance of metal oxides and reduce the cost, it is required to be able to Size combined materials with high specific surface area and high electrical conductivity.

石墨烯（Graphene) 是单原子厚度的碳原子层，是碳原子以 sp²杂化碳原子形成的厚度仅为单层原子的六角平面的排列成蜂巢晶格 (Honeycomb Crystal Lattice)的单层二维晶体。石墨烯具有极其优良的导电性及巨大的比表面积，可以作为金属氧化物负极材料的改性材料。 Graphene is a layer of carbon atoms with a single atomic thickness. It is a single layer of carbon honeycombs formed by sp ² hybridized carbon atoms and arranged in a hexagonal plane of a single layer of atoms to form a honeycomb lattice (Honeycomb Crystal Lattice). Dimensional crystal. Graphene has excellent electrical conductivity and a large specific surface area, and can be used as a modified material for a metal oxide negative electrode material.

CN 101969113 A公开了一种石墨烯基二氧化锡复合锂离子电池负极材料的制备方法，其过程为将锡源前驱体与氧化石墨烯混合，通过水热法制备二氧化锡 /石墨烯复合材料。其具体地包括：首先制备氧化石墨烯纳米片并分散于乙醇溶液中；然后向上述悬浮液中加入一定量的模板剂、四氯化锡和氢氧化钠，搅拌均匀转入高压反应釜于 160°C烘箱中反应 20h，经干燥、过滤、洗涤、再干燥，制得二氧化锡 /石墨烯复合材料。该方法工艺简单，条件温和，成本低廉。通过此法制得的复合材料中二氧化锡颗粒生长均匀，粒径可控制在 2-3nm。经电化学测试，证明所得到的材料具有良好的电化学性能，能够大大提高电子导电能力，为锂离子电池的应用提供了一种加工工艺简单、成本低廉、容量高且安全的锂离子电池负极。然而，该方法制得的二氧化锡 /石墨烯复合材料虽然能够一定程度上提高材料的容量和循环性能，但是提高程度有限，容量衰减也较快（首次可逆容量为 1000mAh/g，经 20个循环后比容量降为 600mAh/g)。而且 Sn0₂作为电极材料在充放电过程中体积变化高达 200~300%，上述方法制得的复合材料没有形成理想的缓冲结构来容纳二氧化锡在充放电过程中的体积膨胀。 CN 101969113 A discloses a method for preparing a negative electrode material of a graphene-based tin dioxide composite lithium ion battery, which comprises mixing a tin source precursor with graphene oxide and preparing a tin dioxide/graphene composite by hydrothermal method. . Specifically, the method comprises the following steps: first preparing a graphene oxide nanosheet and dispersing it in an ethanol solution; then adding a certain amount of a template agent, tin tetrachloride and sodium hydroxide to the suspension, and uniformly transferring the mixture into a high pressure reactor at 160 The reaction was carried out in an oven at ° C for 20 h, dried, filtered, washed and dried to obtain a tin dioxide/graphene composite. The method is simple in process, mild in condition and low in cost. The tin dioxide particles in the composite material prepared by the method are uniformly grown, and the particle diameter can be controlled at 2-3 nm. Electrochemical test proves that the obtained material has good electrochemical performance, can greatly improve the electronic conductivity, and provides a lithium ion battery anode with simple processing, low cost, high capacity and safety for lithium ion battery applications. . However, the tin dioxide/graphene composite prepared by this method can improve the capacity and cycle performance of the material to a certain extent, but the degree of improvement is limited, and the capacity attenuation is also fast (the first reversible capacity is 1000 mAh/g, after 20 The specific capacity after the cycle is reduced to 600 mAh/g). Moreover, the volume change of Sn0 ₂ as an electrode material during charging and discharging is as high as 200-300%. The composite material prepared by the above method does not form an ideal buffer structure to accommodate the volume expansion of tin dioxide during charge and discharge.

文献（Adv. Energy Mater. 2011, 1, 1079-1084 )报道了一种基于多孔石墨烯的硅-石墨烯层状复合材料和基于该负极活性材料的锂离子二次电池，其特点是把成簇的硅夹在具有多孔结构的石墨烯纳米片之间，具体过程为：首先利用 Humers 法制备氧化石墨烯，然后将氧化石墨烯分散到 70%浓度的硝酸溶液中，加入一定量的硅纳米粒子并利用超声波粉碎机对其超声 lh，随后经过抽滤、干燥、高温煅烧最终获得硅-多孔石墨烯层状复合材料。该材料具有发达的空隙结构，超大的比表面积，良好的结构稳定性。基于该负极活性材料的锂离子二次电池具有电池容量高（1100mAh/g)、循环寿命长、高循环稳定性（循环 150次容量保持 99.9%)、快充慢放（15分钟充满，持续使用 1周）的特点。但硅与 8110₂同样在充放电过程中存在体积效应，所以该硅 /多孔石墨烯层状复合材料难以保证使用过程中的结构稳定，限制了其在锂离子电池中的应用。 The literature (Adv. Energy Mater. 2011, 1, 1079-1084) reports a porous graphene-based silicon-graphene layered composite material and a lithium ion secondary battery based on the anode active material, which is characterized by The silicon of the cluster is sandwiched between the graphene nanosheets having a porous structure by first preparing the graphene oxide by the Humers method, then dispersing the graphene oxide into a 70% nitric acid solution, and adding one Quantitative silicon nanoparticles were ultrasonicated for 1 h using an ultrasonic pulverizer, followed by suction filtration, drying, and high-temperature calcination to finally obtain a silicon-porous graphene layered composite. The material has a developed void structure, an extra large specific surface area, and good structural stability. The lithium ion secondary battery based on the negative electrode active material has a high battery capacity (1100 mAh/g), long cycle life, high cycle stability (remaining cycle capacity of 99.9%), fast charge and slow release (15 minutes full, continuous use) 1 week) features. However, silicon has the same volume effect as the 8110 ₂ during charging and discharging. Therefore, the silicon/porous graphene layered composite material is difficult to ensure structural stability during use, which limits its application in lithium ion batteries.

开发一种电容量高、循环性能好并且容量衰减低、体积效应小的锂离子电池负极材料对于开发高性能锂离子电池是非常有意义的。 The development of a lithium ion battery anode material with high capacitance, good cycle performance, low capacity attenuation, and small volume effect is of great significance for the development of high performance lithium ion batteries.

发明内容 Summary of the invention

针对现有技术中锂离子电池负极材料的电容量低、循环性能不好，并且容量衰减严重，而且在充放电过程中体积变化大的不足，本发明公开一种锂离子电池负极用石墨烯复合材料，所述材料将石墨烯与二氧化钛纳米粒子复合，从而结合了石墨烯比表面积大的特点和二氧化钛在脱嵌锂过程中结构变化小的特点，制得电容量高、循环性好、容量衰减低、体积效应小的锂离子电池负极材料。 In view of the prior art, the negative electrode material of the lithium ion battery has low capacitance, poor cycle performance, serious capacity attenuation, and large volume change during charging and discharging, and the invention discloses a graphene composite for a negative electrode of a lithium ion battery. The material combines graphene with titanium dioxide nanoparticles to combine the characteristics of large specific surface area of graphene and small structural change of titanium dioxide during deintercalation of lithium, thereby obtaining high capacitance, good cycleability, and capacity reduction. A low-volume, low-volume lithium-ion battery anode material.

二氧化钛的脱嵌锂电压较高（大约为 1.5V), 并且在有机电解液中的溶解度较小，脱嵌锂过程中的结构变化小，可以避免脱嵌锂过程中的材料体积变化引起的结构变化，从而保证使用的安全性，提高电极材料的循环性能和使用寿命。但是二氧化钛的电导率较低，不能够广泛用于锂离子电池的负极材料中。 The deintercalation lithium voltage of titanium dioxide is relatively high (about 1.5V), and the solubility in the organic electrolyte is small, and the structural change during the process of deintercalating lithium is small, and the structure caused by the volume change of the material during the deintercalation of lithium can be avoided. Changes, thus ensuring the safety of use, improving the cycle performance and service life of the electrode material. However, titanium dioxide has a low electrical conductivity and cannot be widely used in a negative electrode material of a lithium ion battery.

本发明结合石墨烯极其优良的导电性和巨大的比表面积，将二氧化钛进行改性，弥补二氧化钛电导率低的缺点。而且二氧化钛的价格低廉、环境友好、制备工艺简单，是锂离子电池负极材料的合适选择。本发明的目的之一在于提供一种锂离子电池负极用石墨烯复合材料的制备方法。所述方法是将石墨烯类材料在浓酸环境中氧化，超声分散后与钛源混合，经干燥煅烧后制得。 The invention combines the extremely excellent electrical conductivity and the large specific surface area of the graphene to modify the titanium dioxide to make up for the disadvantage of low conductivity of the titanium dioxide. Moreover, titanium dioxide is a suitable choice for the anode material of lithium ion batteries because of its low price, environmental friendliness and simple preparation process. One of the objects of the present invention is to provide a method for preparing a graphene composite material for a negative electrode of a lithium ion battery. The method is characterized in that the graphene-based material is oxidized in a concentrated acid environment, ultrasonically dispersed, mixed with a titanium source, and dried and calcined.

优选地，本发明所述石墨烯类材料选自石墨烯或石墨烯衍生材料。 Preferably, the graphene-based material of the present invention is selected from graphene or graphene-derived materials.

由此，本领域技术人员能够获知的石墨烯类材料均可用于本发明，尤其是具有大的比表面积和好的导电性的石墨烯材料或者石墨烯衍生材料。所谓的石墨烯衍生材料是指在石墨烯材料上引入基团得到的衍生材料，例如石墨烯加氢或者加氟反应后得到的衍生材料，或者石墨烯与聚合物进行结合得到的衍生材料等。石墨烯通过与一些贵金属纳米粒子或者与有机导电高分子材料等形成的复合材料，在电容性能方面表现非常优异。石墨烯衍生材料的获得已经有很多报道，本领域技术人员有能力获得，此处不再赘述。 Thus, graphene-based materials which can be known to those skilled in the art can be used in the present invention, especially graphene materials or graphene-derived materials having a large specific surface area and good electrical conductivity. The so-called graphene-derived material refers to a derivative material obtained by introducing a group onto a graphene material, for example, a derivative material obtained by hydrogenating or adding a fluorine-containing reaction, or a derivative material obtained by combining graphene with a polymer. Graphene is excellent in capacitance performance by a composite material formed with some noble metal nanoparticles or an organic conductive polymer material. There have been many reports on the acquisition of graphene-derived materials, which are available to those skilled in the art and will not be described herein.

优选地，本发明所述石墨烯类材料具有三维结构，且表面含有大量纳米级微孔。进一步优选地，所述石墨烯类材料的电导率 100mS/m，例如电导率为 102mS/m的石墨烯类材料、 118mS/m的石墨烯类材料、 144mS/m的石墨烯类材料等，或者表面具有孔径在 2nm-100nm范围内的微孔的石墨烯类材料，例如石墨烯类材料的表面微孔孔径为 2-4nm、 3-7nm、 4.5-8.8nm、 7-10nm等，更加适合于本发明。本发明最优选比表面积范围在 1500cm²/g-3000cm²/g内的石墨烯类材料，例如比表面积为 1505cm²/g、 1670cm²/g、 2030cm²/g、 2800cm²/g、 2908cm²/g、 3000cm²/g等的石墨烯类材料。 Preferably, the graphene-based material of the present invention has a three-dimensional structure and the surface contains a large number of nano-scale micropores. Further preferably, the graphene-based material has an electric conductivity of 100 mS/m, for example, a graphene-based material having an electric conductivity of 102 mS/m, a graphene-based material of 118 mS/m, a graphene-based material of 144 mS/m, or the like, or A graphene-based material having micropores having a pore diameter in the range of 2 nm to 100 nm, for example, a graphene-based material having a surface micropore diameter of 2-4 nm, 3-7 nm, 4.5-8.8 nm, 7-10 nm, etc., is more suitable for this invention. The most preferred specific surface area of the graphite-based material, the scope of the invention in ^{^{1500cm 2 / g-3000cm 2 /}} g , for example, a specific surface area of ^{^{1505cm 2 / g, 1670cm 2 /}} g, 2030cm 2 / g, 2800cm 2 / g, 2908cm 2 Graphene-based material of /g, 3000 cm ² /g, and the like.

本领域技术人员能够获知的可以制备出表面有大量纳米级微孔的石墨烯材料或者石墨烯衍生材料的方法均可用于实现本发明，典型但非限制性的实例有微波膨化处理氧化石墨烯、利用水合肼等强还原剂还原氧化石墨烯、电化学还原氧化石墨烯、高温加热处理氧化石墨烯等。所述的制备表面有大量微米级孔的石墨烯材料或石墨烯衍生材料的方法，本领域技术人员可以根据掌握的专业知识和查阅相关资料获得。 A method known to those skilled in the art for preparing a graphene material or a graphene-derived material having a large number of nano-scale micropores on the surface can be used to carry out the invention, and a typical but non-limiting example is microwave expansion treatment of graphene oxide, The use of a strong reducing agent such as hydrazine hydrate to reduce graphene oxide, electrochemical reduction of graphene oxide, high temperature heat treatment of graphene oxide, and the like. The preparation surface has a large number of micron holes The method of graphene material or graphene-derived material can be obtained by those skilled in the art based on the professional knowledge and relevant materials.

本发明特别优选能够制备出电导率 100mS/m和 /或表面有大量孔径范围为 2nm-100nm的微孔和 /或比表面积范围在 1500cm²/g-3000cm²/g 内的石墨烯衍生材料的方法用于本发明。例如 CN 102070140 A公开了一种制备高比表面积石墨烯材料的方法。 Conductivity of 100mS / m and / or the surface of the present invention can be prepared particularly preferably have a large pore diameter in the range of 2nm 100nm-micropores and / or a specific surface area in the range of the graphene material derived ^{^{1500cm 2 / g-3000cm 2 /}} g of The method is used in the present invention. For example, CN 102070140 A discloses a process for preparing a high specific surface area graphene material.

CN 102070140 A公开了一种利用强碱处理得到高比表面积石墨烯材料的方法，利用强碱和碳在高温下的反应，热处理或者微波辐照得到的石墨烯粉末进行进一步化学处理，从而快速的、大批量的在石墨烯表面腐蚀出纳米量级的微孔，极大地提高其比表面积，并且高温处理可进一步还原石墨烯，从而保证所得到材料的高导电性。 CN 102070140 A公开的方法制备得到的石墨烯材料不仅具有三维、多孔的结构，其比表面积高达 1500m²/g-3000m²/g，同时所得到的石墨烯材料还具有高的导电性。 CN 102070140 A discloses a method for obtaining a high specific surface area graphene material by treatment with a strong alkali, which utilizes a reaction of a strong base and carbon at a high temperature, heat treatment or microwave irradiation to obtain a graphene powder for further chemical treatment, thereby rapidly Large quantities of micropores are etched on the surface of graphene to greatly increase the specific surface area, and high temperature treatment can further reduce graphene, thereby ensuring high conductivity of the obtained material. The graphene material prepared by the method disclosed in CN 102070140 A has not only a three-dimensional, porous structure, but also a specific surface area of up to 1500 m ² /g to 3000 m ² /g, and the obtained graphene material also has high conductivity.

优选地，本发明所述表面含有大量纳米级微孔的具有三维结构的石墨烯类材料的制备过程为：将热处理或者微波辐照得到的石墨烯粉末与强碱反应，经过后处理制备得到。 Preferably, the preparation process of the graphene-based material having a three-dimensional structure containing a large number of nano-scale micropores on the surface of the present invention is: reacting the graphene powder obtained by heat treatment or microwave irradiation with a strong base, and preparing by post-treatment.

具体地，制备表面含有大量纳米级微孔的具有三维结构的石墨烯材料步骤包括：（1 ) 将氧化石墨置于水中，进行超声处理，得到氧化石墨悬浮液；（2 ) 配置强碱水溶液；（3 ) 将步骤（2 ) 的强碱水溶液加入到步骤（1 ) 的氧化石墨悬浮液中，搅拌，蒸发，干燥；（4)将步骤（3 )干燥后所得到的固体烧结；（5 ) 将步骤（4) 得到的固体进行水洗、过滤、干燥。 Specifically, the step of preparing a graphene material having a three-dimensional structure containing a plurality of nano-scale micropores includes: (1) placing the graphite oxide in water and performing ultrasonic treatment to obtain a graphite oxide suspension; (2) configuring a strong alkali aqueous solution; (3) adding the strong alkali aqueous solution of the step (2) to the graphite oxide suspension of the step (1), stirring, evaporating, and drying; (4) sintering the solid obtained after the step (3) is dried; (5) The solid obtained in the step (4) is washed with water, filtered, and dried.

优选地，在所述石墨烯的制备方法中，步骤（1 )所述超声时间为 l-5h，例如 lh、 1.2h、 2h、 2.4h、 3.5h、 4.1h、 4.9h、 5h等，优选 2-3h，进一步优选 2.5h。优选地，步骤（1 )所述氧化石墨在水中的浓度为 0.01-10mg/mL，例如 0.01mg/mL、 0.04mg/mL、 0.13mg/mL、 0.94mg/mL、 1.6mg/mL、 2.34mg/mL、 3.67mg/mL、 4.89mg/mL、 5.2mg/mL、 7.1mg/mL、 9.42mg/mL、 lOmg/mL等，优选 2-5mg/mL，进一步优选 4mg/mL。优选地，步骤（2) 所述强碱的浓度为 0.2-20mol/L，例如 0.2mol/L、 0.4mol/L、 3.1mol/L、 7.6mol/L、 9.9mol/L、 16.1mol/L、 18.7mol/L、 20mol/L 等，优选 3-15mol/L，进一步优选 10mol/L。优选地，步骤（2) 中，强碱与氧化石墨的质量比为 ( 1-50) :1，例如 1:1、 5:1、 13: 1、 21:1、 39:1、 44: 1、 50: 1等，优选（5-33 ) :1。优选地，步骤（4 ) 所述烧结的温度为 700-1200°C，例如 700 °C、 705°C、 760°C、 920°C、 1060 °C、 1137°C、 1190 °C、 1200°C等，优选 750-1180 °C。 Preferably, in the method for preparing graphene, the ultrasonic time of step (1) is l-5h, such as lh, 1.2h, 2h, 2.4h, 3.5h, 4.1h, 4.9h, 5h, etc., preferably 2-3 h, further preferably 2.5 h. Preferably, the concentration of the graphite oxide in the step (1) in water is 0.01-10 mg/mL, for example, 0.01 mg/mL, 0.04 mg/mL, 0.13 mg/mL, 0.94 mg/mL, 1.6 mg/mL, 2.34 mg. /mL, 3.67 mg/mL, 4.89 mg/mL, 5.2 mg/mL, 7.1 mg/mL, 9.42 mg/mL, 10 mg/mL, etc., preferably 2-5 mg/mL, further preferably 4 mg/mL. Preferably, the concentration of the strong base in the step (2) is 0.2-20 mol/L, for example, 0.2 mol/L, 0.4 mol/L, 3.1 mol/L, 7.6 mol/L, 9.9 mol/L, and 16.1 mol/L. 18.7 mol/L, 20 mol/L, etc., preferably 3-15 mol/L, further preferably 10 mol/L. Preferably, in the step (2), the mass ratio of the strong base to the graphite oxide is (1-50) :1, for example, 1:1, 5:1, 13:1, 21:1, 39:1, 44:1 50:1, etc., preferably (5-33):1. Preferably, the sintering temperature of the step (4) is 700-1200 ° C, such as 700 ° C, 705 ° C, 760 ° C, 920 ° C, 1060 ° C, 1137 ° C, 1190 ° C, 1200 ° C or the like, preferably 750-1180 °C.

本领域技术人员应该明了，本发明所述的表面含有大量纳米级微孔和 /或具有三维结构的石墨烯材料的制备方法并不限于以上所述的方法，任何能够制备得到复合要求的石墨烯均可用于本发明。 It should be apparent to those skilled in the art that the preparation method of the graphene material having a large number of nano-scale micropores and/or a three-dimensional structure on the surface of the present invention is not limited to the method described above, and any graphene capable of preparing a composite requirement can be prepared. Both can be used in the present invention.

优选地，本发明所述钛源为钛源前驱体和 /或纳米二氧化钛粒子；所述钛源前驱体优选自四氯化钛、钛酸正丁酯和钛酸异丙酯中的任意 1种或至少 2种的组合，所述组合例如四氯化钛 /钛酸正丁酯、钛酸异丙酯 /钛酸正丁酯、四氯化钛 /钛酸异丙酯 /钛酸正丁酯等；所述纳米二氧化钛粒子的粒径优选为 10-500nm，例如 10nm、 15nm、 33nm、 69nm、 80nm、 150nm、 300nm、 450nm、 488nm、 500nm 等。 Preferably, the titanium source of the present invention is a titanium source precursor and/or nano titanium dioxide particles; and the titanium source precursor is preferably any one of titanium tetrachloride, n-butyl titanate and isopropyl titanate. Or a combination of at least two, such as titanium tetrachloride/n-butyl titanate, isopropyl titanate/n-butyl titanate, titanium tetrachloride/isopropyl titanate/n-butyl titanate The nano titanium dioxide particles preferably have a particle diameter of 10 to 500 nm, for example, 10 nm, 15 nm, 33 nm, 69 nm, 80 nm, 150 nm, 300 nm, 450 nm, 488 nm, 500 nm, or the like.

作为优选技术方案，本发明所述方法包括如下步骤： As a preferred technical solution, the method of the present invention comprises the following steps:

( 1 )将石墨烯类材料在浓酸环境中氧化得到氧化石墨类材料，经超声分散于分散剂中得悬浮液 a; (1) oxidizing a graphene-based material in a concentrated acid environment to obtain a graphite oxide-based material, which is ultrasonically dispersed in a dispersing agent to obtain a suspension a;

(2) 将钛源添加到悬浮液 a中混合均匀，并水解得到悬浮液 b; (3 ) 将悬浮液 b搅拌均匀，经抽滤或者喷雾干燥得到块状或者粉末材料，将块状或者粉末材料煅烧得到二氧化钛 /石墨烯复合材料。 (2) adding a titanium source to the suspension a, mixing well, and hydrolyzing to obtain a suspension b; (3) Stirring the suspension b uniformly, by suction filtration or spray drying to obtain a bulk or powder material, and calcining the bulk or powder material to obtain a titanium dioxide/graphene composite material.

优选地，本发明步骤（1 ) 所述浓酸选自浓硫酸、浓硝酸、浓高氯酸、浓磷酸和浓盐酸中的任意 1种或至少 2种的组合，所述组合例如浓硫酸 /浓硝酸、浓高氯酸 /浓磷酸、浓盐酸 /浓硫酸 /浓硝酸等，优选浓硫酸、浓盐酸、浓高氯酸\浓磷酸的组合、浓硝酸 \浓高氯酸\浓盐酸的组合，进一步优选浓硫酸和 /或浓高氯酸。 Preferably, the concentrated acid in the step (1) of the present invention is selected from any one or a combination of at least two of concentrated sulfuric acid, concentrated nitric acid, concentrated perchloric acid, concentrated phosphoric acid and concentrated hydrochloric acid, such as concentrated sulfuric acid/ Concentrated nitric acid, concentrated perchloric acid / concentrated phosphoric acid, concentrated hydrochloric acid / concentrated sulfuric acid / concentrated nitric acid, etc., preferably a combination of concentrated sulfuric acid, concentrated hydrochloric acid, concentrated perchloric acid / concentrated phosphoric acid, concentrated nitric acid \ concentrated perchloric acid \ concentrated hydrochloric acid Further, concentrated sulfuric acid and/or concentrated perchloric acid are further preferred.

优选地，本发明步骤（1 ) 所述氧化为用氧化剂进行氧化；所述氧化的时间为 0.5h-5h，例如 0.5h、 0.6h、 0.7h、 2h、 4h、 4.8h、 4.9h、 5h等; 所述氧化剂优选自高锰酸钾、硝酸盐、高氯酸盐、过氧化氢、铬酸盐和过硫酸盐中的任意 1 种或至少 2种的组合，例如高锰酸钾、硝酸钠、铬酸钾、过硫酸钾、过氧化氢、高锰酸钾\硝酸钠的组合、硝酸钠 \过硫酸钠的组合、高锰酸钾\铬酸钾 \过硫酸钾的组合，优选硝酸盐、铬酸盐、过硫酸盐中的任意 1种或至少 2种的组合；最优选高锰酸钾和 /或过氧化氢。 Preferably, the oxidation in the step (1) of the present invention is carried out by oxidation with an oxidizing agent; the oxidation time is 0.5 h to 5 h, for example, 0.5 h, 0.6 h, 0.7 h, 2 h, 4 h, 4.8 h, 4.9 h, 5 h. And the oxidizing agent is preferably selected from any one or a combination of at least two of potassium permanganate, nitrate, perchlorate, hydrogen peroxide, chromate and persulphate, such as potassium permanganate, nitric acid a combination of sodium, potassium chromate, potassium persulfate, hydrogen peroxide, potassium permanganate/sodium nitrate, a combination of sodium nitrate/sodium persulfate, potassium permanganate, potassium chromate, potassium persulfate, preferably nitric acid Any one or a combination of at least two of salts, chromates, persulfates; potassium permanganate and/or hydrogen peroxide are most preferred.

优选地，本发明步骤（1 ) 所述分散剂为水，或水与乙醇、异丙醇、乙二醇中的任意 1中或至少 2种的组合，例如所述分散剂为水、乙醇 /水、异丙醇 /水、乙二醇 /水、乙醇 /丙二醇 /水、乙醇 /异丙醇 /水、异丙醇 /乙二醇 /水等，本发明所述分散剂中至少含有 20%体积的水。本发明所述分散剂优选自水、水 /乙醇、水 / 乙醇 /丙二醇中的任意 1种或至少 2种的组合，进一步优选水。 Preferably, the dispersing agent in the step (1) of the present invention is water, or a combination of water and any one or at least two of ethanol, isopropyl alcohol and ethylene glycol, for example, the dispersing agent is water, ethanol/ Water, isopropanol/water, ethylene glycol/water, ethanol/propylene glycol/water, ethanol/isopropanol/water, isopropanol/ethylene glycol/water, etc., the dispersant of the present invention contains at least 20% Volume of water. The dispersing agent of the present invention is preferably any one or a combination of at least two of water, water/ethanol, water/ethanol/propylene glycol, and more preferably water.

步骤（1 )所述的超声分散为本领域技术人员所熟知的技术，超声的功率和超声时间的选择，本领域技术人员可根据自己掌握的专业知识进行选择，在此不再赘述。 The ultrasonic dispersion described in the step (1) is a technique well known to those skilled in the art, and the selection of the power of the ultrasonic wave and the ultrasonic time can be selected by those skilled in the art according to their own professional knowledge, and will not be described herein.

为了使氧化石墨类材料在悬浮液 a中分散的更加均匀稳定，本发明步骤（2) 中，优选向所述悬浮液添加表面活性剂，所添加的表面活性剂可以是本领域技术人员能够获知的任何一种表面活性剂。 In order to make the dispersion of the graphite oxide-based material in the suspension a more uniform and stable, in the step (2) of the present invention, it is preferred to add a surfactant to the suspension, and the added surfactant may be in the art. Any surfactant known to the surgeon.

优选地，本发明所述表面活性剂选自十二垸基磺酸钠、硬脂酸、 PVA 中的任意 1种或至少 2种的组合，所述组合例如十二垸基苯磺酸钠 /硬脂酸、 PVA/硬脂酸 /十二垸基苯磺酸钠等，优选十二垸基磺酸钠。优选地，所述表面活性剂的添加量为 0-5wt%, 例如 0.1wt%、 0.6wt%、 1.2wt%、 2.2wt%、 3.6wt%、 4.4wt%、 4.9wt%、 5.0wt%等。所述表面活性剂的添加量为 0wt%是指在制备过程中不添加表面活性剂。 Preferably, the surfactant of the present invention is selected from any one or a combination of at least two of sodium dodecylsulfonate, stearic acid, and PVA, such as sodium dodecylbenzenesulfonate/ Stearic acid, PVA/stearic acid/sodium dodecylbenzenesulfonate, etc., preferably sodium dodecylsulfonate. Preferably, the surfactant is added in an amount of 0 to 5% by weight, for example, 0.1% by weight, 0.6% by weight, 1.2% by weight, 2.2% by weight, 3.6% by weight, 4.4% by weight, 4.9% by weight, 5.0% by weight, etc. . The addition amount of the surfactant of 0% by weight means that no surfactant is added during the preparation.

本发明中，石墨烯类材料的浓度太大容易凝聚，不利于复合材料的制备，浓度太小，则复合材料的网状三明治结构很难形成，由此，本发明步骤（2) 所述悬浮液 b中，石墨烯类材料的质量百分含量为 0.1wt%-15wt%，例如 0.1wt%、 0.11wt%、 0.12wt%、 3wt%、 5wt%、 8wt%、 9wt%、 9.8wt%、 9.9wt%、 10wt%、 10.6wt%、 13.5wt%、 14.8wt%、 15wt%等，优选 0.1-10wt%，进一步优选 3-10wt%。 In the present invention, the concentration of the graphene-based material is too large to be easily aggregated, which is disadvantageous for the preparation of the composite material. If the concentration is too small, the network sandwich structure of the composite material is difficult to form, and thus the suspension of the step (2) of the present invention In the liquid b, the graphene-based material has a mass percentage of 0.1 wt% to 15 wt%, for example, 0.1 wt%, 0.11 wt%, 0.12 wt%, 3 wt%, 5 wt%, 8 wt%, 9 wt%, 9.8 wt%, 9.9 wt%, 10 wt%, 10.6 wt%, 13.5 wt%, 14.8 wt%, 15 wt%, etc., preferably 0.1 to 10 wt%, further preferably 3 to 10 wt%.

优选地，本发明步骤（2) 所述悬浮液 b中，钛源和氧化石墨类材料的质量比为 1:3-8，例如 1:3、 1:3.5、 1:4、 1:4.2、 1:4.8、 1:5、 1:5.9、 1:6、 1:7.3、 1:7.9、 1:8等，优选 1:4-6，进一步优选 1:5。 Preferably, in the suspension b of the step (2) of the present invention, the mass ratio of the titanium source to the graphite oxide-based material is 1:3-8, such as 1:3, 1:3.5, 1:4, 1:4.2, 1:4.8, 1:5, 1:5.9, 1:6, 1:7.3, 1:7.9, 1:8, etc., preferably 1:4-6, more preferably 1:5.

优选地，步骤（2) 所述水解温度为 50-90 °C，例如 50°C、 55°C、 63°C、 82 °C、 89°C、 90°C等，优选 50-70°C，进一步优选 60°C。 Preferably, the hydrolysis temperature in the step (2) is 50-90 ° C, for example, 50 ° C, 55 ° C, 63 ° C, 82 ° C, 89 ° C, 90 ° C, etc., preferably 50-70 ° C. Further, 60 ° C is preferred.

优选地，步骤 (2) 所述水解水解时间为 l-8h，例如 lh、 1.3h、 3.2h、 5.1h、 6h、 7.4h、 8h等，优选 l-6h，进一步优选 2h。 Preferably, the hydrolysis hydrolysis time in the step (2) is from 1 to 8 hours, for example, lh, 1.3h, 3.2h, 5.1h, 6h, 7.4h, 8h, etc., preferably l-6h, further preferably 2h.

优选地，本发明步骤（3 )所述的喷雾干燥的温度为 100°C-200°C，例如 101 °C、 106°C、 110°C、、 120 °C、 125 °C、 150°C、 156°C、 175 °C、 180 °C、 189 °C、 195°C、 200°C等，优选 120°C-180°C。 Preferably, the spray drying temperature according to the step (3) of the present invention is from 100 ° C to 200 ° C, for example, 101 ° C, 106 ° C, 110 ° C, 120 ° C, 125 ° C, 150 ° C. 156 ° C, 175 ° C, 180 ° C, 189 ° C, 195 ° C, 200 ° C, etc., preferably 120 ° C - 180 ° C.

优选地，本发明步骤（3 ) 所述煅烧为高温煅烧处理，所述煅烧温度为 500 °C-1200°C，例如 500°C、 510°C、 520 °C、 800°C、 1000 °C、 1100 °C、 1190 °C、 1200 °C等，优选 500°C-1000°C ;优选地，所述煅烧时间为 4-15h，例如 4h、 4.6h、 5.9h、 7.2h、 9.9h、 10h、 13.2h、 14.9h、 15h等，优选 4-8h，进一步优选 6h。 Preferably, the calcination in the step (3) of the present invention is a high temperature calcination treatment, and the calcination temperature is 500. °C-1200 °C, such as 500 ° C, 510 ° C, 520 ° C, 800 ° C, 1000 ° C, 1100 ° C, 1190 ° C, 1200 ° C, etc., preferably 500 ° C - 1000 ° C; Preferably, the calcination time is 4-15 h, such as 4 h, 4.6 h, 5.9 h, 7.2 h, 9.9 h, 10 h, 13.2 h, 14.9 h, 15 h, etc., preferably 4-8 h, further preferably 6 h.

所述高温煅烧优选在保护气氛下进行，所述保护气氛为氢气和惰性气体的组合。本领域技术人员可以根据自己掌握的技术知识自由选择保护气氛的气体成分，例如氦气、氖气、氩气、氪气、氙气、氢气和氮气中的任意 1种或至少 2 种的组合。本发明优选所述惰性气体为氩气和 /或氮气；进一步优选地，所述保护气氛为氢气 /氩气的组合和 /或氢气 /氮气的组合，特别优选氢气 /氩气的组合。 The high temperature calcination is preferably carried out under a protective atmosphere which is a combination of hydrogen and an inert gas. Those skilled in the art can freely select a gas component that protects the atmosphere according to their own technical knowledge, such as any one or a combination of at least two of helium, neon, argon, helium, neon, hydrogen, and nitrogen. Preferably, the inert gas is argon and/or nitrogen; further preferably, the protective atmosphere is a combination of hydrogen/argon and/or a combination of hydrogen/nitrogen, particularly preferably a combination of hydrogen/argon.

作为可选技术方案，本发明所述锂离子电池负极用石墨烯复合材料的制备方法包括如下步骤：（1 ) 将石墨烯衍生材料在浓盐酸环境中，加入高锰酸钾对其进行氧化，得到氧化石墨烯衍生材料，然后经超声分散到水中，得到分散液 a; As an alternative technical solution, the method for preparing a graphene composite material for a negative electrode of a lithium ion battery according to the present invention comprises the following steps: (1) oxidizing the graphene-derived material in a concentrated hydrochloric acid environment by adding potassium permanganate, Obtaining a graphene oxide-derived material, and then dispersing it into water by ultrasonication to obtain a dispersion a;

(2)将四氯化钛按照与氧化石墨烯 1:5的比例添加到悬浮液 a中并在 60°C下水解 2小时得到悬浮液 b; (3 )将悬浮液 b搅拌均匀，经抽滤得到粉末，将粉末在氮气气氛中 800 °C下煅烧得到二氧化钛 /石墨烯复合材料。 (2) adding titanium tetrachloride to the suspension a in a ratio of 1:5 with graphene oxide and hydrolyzing at 60 ° C for 2 hours to obtain a suspension b; (3) stirring the suspension b uniformly, by pumping The powder was filtered, and the powder was calcined at 800 ° C in a nitrogen atmosphere to obtain a titanium oxide/graphene composite.

作为优选技术方案，本发明所述锂离子电池负极用石墨烯复合材料的制备方法包括如下步骤：（1 ) 将石墨烯衍生材料在浓高氯酸环境中，加入硝酸钠和过硫酸钾对其进行氧化，得到氧化石墨烯衍生材料，然后经超声分散到水中，得到悬浮液 a; (2) 将钛酸丁酯按照与氧化石墨烯 1:5的比例添加到悬浮液 a中并在 60°C下水解 2小时得到悬浮液 b; (3 ) 将悬浮液 b搅拌均匀，经喷雾干燥得到粉末，将粉末在氮气气氛中 800°C下煅烧得到二氧化钛 /石墨烯复合材料。 As a preferred technical solution, the method for preparing a graphene composite material for a negative electrode of a lithium ion battery according to the present invention comprises the following steps: (1) adding a graphene-derived material to a concentrated perchloric acid environment, adding sodium nitrate and potassium persulfate thereto Oxidation, obtaining a graphene oxide-derived material, and then ultrasonically dispersing into water to obtain a suspension a; (2) adding butyl titanate to the suspension a in a ratio of 1:5 with graphene oxide at 60° Hydrolysis was carried out for 2 hours at C to obtain a suspension b; (3) The suspension b was uniformly stirred, spray-dried to obtain a powder, and the powder was calcined at 800 ° C in a nitrogen atmosphere to obtain a titanium oxide/graphene composite material.

本发明的目的之二是提供一种由本发明所述的方法制备得到锂离子电池负极用的石墨烯复合材料。 Another object of the present invention is to provide a graphene composite material for use in preparing a negative electrode for a lithium ion battery by the method of the present invention.

所述石墨烯负极材料为三明治结构，石墨烯的片层与片层之间夹有二氧化钛纳米粒子。优选地，石墨烯负极材料为层状网络结构，每层石墨烯上分散有二氧化钛纳米粒子，并且石墨烯片层中间由二氧化钛纳米粒子分散开，其中至少有两个石墨烯片层结合到二氧化钛上。进一步优选地，所述石墨烯片层具有三维结构、且表面有大量的纳米级微孔。 The graphene anode material is a sandwich structure, and the graphene is sandwiched between the sheet layer and the sheet layer. Titanium nanoparticles. Preferably, the graphene anode material is a layered network structure, and each layer of graphene is dispersed with titanium dioxide nanoparticles, and the graphene sheet layer is dispersed by titanium dioxide nanoparticles, wherein at least two graphene sheets are bonded to the titanium dioxide. . Further preferably, the graphene sheet layer has a three-dimensional structure and a large number of nano-scale micropores on the surface.

优选地，本发明所述锂离子电池负极片具有相互连通的网络状孔洞通道，比容量 390mAh/g，例如 390mAh/g、 395mAh/g、 400mAh/g、 403mAh/g等。 Preferably, the negative electrode sheet of the lithium ion battery of the present invention has interconnected network-like pore channels having a specific capacity of 390 mAh/g, for example, 390 mAh/g, 395 mAh/g, 400 mAh/g, 403 mAh/g, and the like.

本发明的目的之三是提供一种锂离子电池负极用石墨烯复合材料的用途，所述负极材料用于制备锂离子二次电池。 A third object of the present invention is to provide a use of a graphene composite material for a negative electrode of a lithium ion battery, which is used for preparing a lithium ion secondary battery.

本发明所述锂离子电池负极用石墨烯复合材料可用于制备锂离子电池，尤其可用于制备锂离子二次电池的负极片，所制备得到的锂离子二次电池具有容量高、安全性好、循环性能优良以及寿命长的性质。本发明典型但非限制性的用途是制备钮扣式锂离子电池。 The graphene composite material for a negative electrode of a lithium ion battery of the invention can be used for preparing a lithium ion battery, and can be especially used for preparing a negative electrode sheet of a lithium ion secondary battery, and the prepared lithium ion secondary battery has high capacity and good safety. Excellent cycle performance and long life. A typical but non-limiting use of the invention is in the fabrication of button-type lithium ion batteries.

与现有技术相比，本发明具有以下有益效果： Compared with the prior art, the present invention has the following beneficial effects:

( 1 )本发明所制得的二氧化钛 /石墨烯复合材料制备的锂电池负极片，极片内二氧化钛 /石墨烯负极材料为层状三明治结构，其中石墨烯具有三维结构、且表面有大量的纳米级微孔。这使得片内分布着许多网络状相互连通的孔径通道，锂离子电解液可以在这些孔径通道中充分自由地扩散，提高材料的电导率，降低电极片的电阻，且该复合材料在充放电过程中具有良好的结构稳定性。 (1) The lithium battery negative electrode sheet prepared by the titanium dioxide/graphene composite material prepared by the invention, the titanium dioxide/graphene anode material in the pole piece is a layered sandwich structure, wherein the graphene has a three-dimensional structure and a large number of nanometers on the surface. Grade micropores. This allows a number of network-connected aperture channels to be distributed in the chip. The lithium ion electrolyte can diffuse sufficiently freely in these aperture channels, improve the electrical conductivity of the material, reduce the resistance of the electrode sheets, and the composite material is charged and discharged. Has good structural stability.

(2)用所述二氧化钛 /石墨烯复合材料作为锂离子二次电池负极材料制备得到的锂离子二次电池具有电池容量高（可逆容量高达 463mAh/g)、安全性好、循环性能优良（循环 500次容量保持 95%以上）以及寿命长的优点。 (2) The lithium ion secondary battery prepared by using the titanium dioxide/graphene composite material as a negative electrode material for a lithium ion secondary battery has high battery capacity (reversible capacity up to 463 mAh/g), good safety, and excellent cycle performance (circulation 500 times capacity is maintained above 95%) and the advantage of long life.

附图说明 DRAWINGS

图 1是多孔石墨烯纳米材料的微观结构示意图；图 2是经过氧化的石墨烯纳米片的微观结构示意图； 1 is a schematic view showing the microstructure of a porous graphene nano material; 2 is a schematic view showing the microstructure of an oxidized graphene nanosheet;

图 3是氧化石墨烯 /二氧化钛复合材料的微观结构示意图； 3 is a schematic view showing the microstructure of a graphene oxide/titanium dioxide composite material;

图 4是石墨烯 /二氧化钛复合材料的微观结构示意图。 Figure 4 is a schematic diagram of the microstructure of a graphene/titanium dioxide composite.

具体实施方式 detailed description

为便于理解本发明，本发明列举实施例如下。本领域技术人员应该明了，所述实施例仅仅是帮助理解本发明，不应视为对本发明的具体限制。 In order to facilitate the understanding of the present invention, the present invention is exemplified by the following. It should be understood by those skilled in the art that the present invention is not to be construed as limited.

实施例一 Embodiment 1

1、制备二氧化钛 /石墨烯复合材料： 1. Preparation of titanium dioxide/graphene composite materials:

( 1 )称取 l.Og石墨烯三维衍生材料（其表面有大量孔径范围为 2nm-100nm 的微孔），加入到 50ml浓硫酸中，搅拌下缓缓加入 3.5g高锰酸钾，室温搅拌反应 0.5小时，然后缓缓加入 100ml去离子水，滴加过氧化氢直至没有气泡产生，过滤并用去离子水洗涤至中性，干燥得到氧化石墨烯三维衍生材料。将干燥得到的氧化石墨烯三维衍生材料溶于水溶液中，超声得到分散稳定的氧化石墨烯三维衍生材料水溶液。 (1) Weigh l.Og graphene three-dimensional derivative material (there are a large number of pores with a pore size ranging from 2nm to 100nm), add it to 50ml concentrated sulfuric acid, slowly add 3.5g potassium permanganate under stirring, stir at room temperature The reaction was carried out for 0.5 hour, then 100 ml of deionized water was slowly added, hydrogen peroxide was added dropwise until no bubbles were generated, filtered and washed with deionized water until neutral, and dried to obtain a graphene oxide three-dimensional derivative material. The dried graphene oxide three-dimensional derivative material is dissolved in an aqueous solution, and ultrasonically obtained to obtain a dispersion-stabilized aqueous solution of a graphene oxide three-dimensional derivative material.

(2)按照四氯化钛与氧化石墨烯质量比为 1:5的比例向步骤（1 )得到的悬浮液加入四氯化钛并在 60°C下水解 2小时得到悬浮液 b。通过搅拌与超声混合均匀后，将此混合体系经抽滤得到固体粉末。将所得固体粉末在 700°C氩气和氢气的混合气体气氛保护下高温煅烧 6h，氧化石墨烯衍生材料被还原成石墨烯衍生材料，得到二氧化钛 /石墨烯复合层状材料。 (2) Titanium tetrachloride was added to the suspension obtained in the step (1) in a ratio of 1:5 by mass ratio of titanium tetrachloride to graphene oxide, and hydrolyzed at 60 ° C for 2 hours to obtain a suspension b. After mixing with ultrasonication by stirring, the mixed system was suction filtered to obtain a solid powder. The obtained solid powder was calcined at a high temperature for 6 hours under a mixed gas atmosphere of argon gas and hydrogen gas at 700 ° C, and the graphene oxide-derived material was reduced to a graphene-derived material to obtain a titania/graphene composite layered material.

2、制备钮扣式电池：将二氧化钛 /石墨烯复合材料粉末和粘结剂聚偏氟乙烯按质量比 9:1混合均匀涂敷于铜箔上制成极片。在氩气气氛手套箱中，以锂片为负极， Cegard2500薄膜为隔膜，电解液为 1M LiPF₆/碳酸乙烯酯（EC) : 碳酸二甲酯（DMC) : 碳酸甲乙酯（EMC) =1: 1:1，组装成钮扣式电池。在恒温条件下，对电池在 0.01V-1.5V电压范围内进行恒流充放电测试，可逆容量高达 463mAh/g，经 500次充放电循环后容量保持 94%。 2. Preparation of button battery: The titanium dioxide/graphene composite powder and the binder polyvinylidene fluoride are uniformly applied to the copper foil at a mass ratio of 9:1 to form a pole piece. In the argon atmosphere glove box, the lithium plate is used as the negative electrode, the Cegard 2500 film is used as the separator, and the electrolyte is 1M LiPF ₆ /ethylene carbonate (EC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) =1 : 1:1, assembled into a button battery. Under constant temperature conditions, the battery was tested for constant current charge and discharge in the voltage range of 0.01V-1.5V. The reversible capacity was up to 463mAh/g, and the capacity was maintained at 94% after 500 charge and discharge cycles.

实施例二 Embodiment 2

( 1 )称取 5.0g石墨烯三维衍生材料（其电导大于 100mS/m)，加入到 100ml 浓硫酸中，搅拌下缓缓加入 17.5g高锰酸钾，室温搅拌反应 1.5小时，然后缓缓加入 300ml去离子水，滴加过氧化氢直至没有气泡产生，过滤并用去离子水洗涤至中性，干燥得到氧化石墨烯三维衍生材料。将干燥得到的石墨烯三维衍生材料溶于水溶液中，超声得到分散稳定的石墨烯三维衍生材料水溶液。 (1) Weigh 5.0g of graphene three-dimensional derivative material (its conductance is greater than 100mS / m), add to 100ml concentrated sulfuric acid, slowly add 17.5g potassium permanganate under stirring, stir the reaction at room temperature for 1.5 hours, then slowly join 300 ml of deionized water, hydrogen peroxide was added dropwise until no bubbles were generated, filtered and washed with deionized water until neutral, and dried to obtain a graphene oxide three-dimensional derivative material. The dried graphene three-dimensional derivative material is dissolved in an aqueous solution, and ultrasonically obtained to obtain a dispersion-stabilized graphene three-dimensional derivative material aqueous solution.

(2)按照四氯化钛与氧化石墨烯质量比为 1:5的比例向步骤（1 )得到的悬浮液加入四氯化钛并在 60°C下水解 2小时得到悬浮液 b。通过搅拌与超声混合均匀后，将此混合体系在 150°C下喷雾干燥得到固体粉末。将此粉末在 850°C氩气和氢气保护下高温煅烧 6小时，氧化石墨烯衍生材料被还原成石墨烯衍生材料，得到二氧化钛 /石墨烯复合材料。 (2) Titanium tetrachloride was added to the suspension obtained in the step (1) in a ratio of 1:5 by mass ratio of titanium tetrachloride to graphene oxide, and hydrolyzed at 60 ° C for 2 hours to obtain a suspension b. After mixing with ultrasonication by stirring, the mixed system was spray-dried at 150 ° C to obtain a solid powder. The powder was calcined at a high temperature for 6 hours under argon and hydrogen protection at 850 ° C, and the graphene oxide-derived material was reduced to a graphene-derived material to obtain a titania/graphene composite.

2、在恒温条件下，对电池在 0.01V~1.5V电压范围内进行恒流充放电测试，可逆容量高达 445mAh/g，经 500次充放电循环后容量保持 95.1% 2. Under constant temperature conditions, the battery is tested for constant current charge and discharge in the voltage range of 0.01V~1.5V. The reversible capacity is up to 445mAh/g, and the capacity remains 95.1% after 500 charge and discharge cycles.

实施例三 Embodiment 3

( 1 )称取 l.Og石墨烯三维衍生材料（其电导大于 100mS/m)，加入到 50ml 浓硫酸中，搅拌下缓缓加入 4g铬酸钾，室温搅拌反应 5小时，然后缓缓加入 100ml 去离子水，滴加过氧化氢直至没有气泡产生，过滤并用去离子水洗涤至中性，干燥得到氧化石墨烯三维衍生材料。将干燥得到的石墨烯三维衍生材料溶于水溶液中，超声得到分散稳定的石墨烯三维衍生材料水溶液。 (2)按照四氯化钛与氧化石墨烯质量比为 1:5的比例向步骤（1 )得到的悬浮液加入四氯化钛并在 60°C下水解 2小时得到悬浮液 b。通过搅拌与超声混合均匀后，将此混合体系在 200°C下进行喷雾干燥手段得到固体粉末。将所得固体粉末在 1200°C氩气和氢气保护下高温煅烧 6h，氧化石墨烯衍生材料被还原成石墨烯衍生材料，得到二氧化钛 /石墨烯复合材料。 (1) Weigh l.Og graphene three-dimensional derivative material (the conductance is greater than 100mS / m), add to 50ml concentrated sulfuric acid, slowly add 4g of potassium chromate while stirring, stir the reaction at room temperature for 5 hours, then slowly add 100ml Deionized water, hydrogen peroxide was added dropwise until no bubbles were generated, filtered and washed with deionized water until neutral, and dried to obtain a graphene oxide three-dimensional derivative material. The dried graphene three-dimensional derivative material is dissolved in an aqueous solution, and ultrasonically obtained to obtain a dispersion-stabilized graphene three-dimensional derivative material aqueous solution. (2) Titanium tetrachloride was added to the suspension obtained in the step (1) in a ratio of 1:5 by mass ratio of titanium tetrachloride to graphene oxide, and hydrolyzed at 60 ° C for 2 hours to obtain a suspension b. After mixing with ultrasonication by stirring, the mixed system was subjected to spray drying at 200 ° C to obtain a solid powder. The obtained solid powder was calcined at a high temperature for 6 hours under the protection of argon gas and hydrogen at 1200 ° C, and the graphene oxide-derived material was reduced to a graphene-derived material to obtain a titania/graphene composite material.

2、在恒温条件下，对电池在 0.01V~1.5V电压范围内进行恒流充放电测试，可逆容量高达 458mAh/g，经 500次充放电循环后容量保持 91%。 2. Under constant temperature conditions, the battery is tested for constant current charge and discharge in the voltage range of 0.01V~1.5V. The reversible capacity is up to 458mAh/g, and the capacity is maintained at 91% after 500 charge and discharge cycles.

实施例四 Embodiment 4

1、制备表面含有大量纳米级微孔的三维石墨烯材料，包括如下步骤： 1. Prepare a three-dimensional graphene material having a large number of nano-scale micropores on the surface, including the following steps:

( 1 ) 将氧化石墨置于水中（氧化石墨的浓度为 4mg/mL)，进行超声处理，超声功率 200W, 超声时间 2.5h，得到氧化石墨悬浮液；（2) 配置 7mol/L的氢氧化钠水溶液；（3 ) 将步骤（2) 的氢氧化钠水溶液加入到步骤（1 ) 的氧化石墨悬浮液中（保证氢氧化钠与氧化石墨的质量比为 40:1 )，搅拌，蒸发，干燥； (4)将步骤（3 ) 干燥后所得到的固体在 1000°C下烧结；（5 )将步骤（4)得到的固体进行水洗、过滤、干燥得到表面含有大量纳米级微孔的三维石墨烯材料。 (1) Place the graphite oxide in water (the concentration of graphite oxide is 4mg/mL), perform ultrasonic treatment, ultrasonic power 200W, ultrasonic time 2.5h, to obtain graphite oxide suspension; (2) configure 7mol/L sodium hydroxide (3) adding the aqueous sodium hydroxide solution of step (2) to the graphite oxide suspension of step (1) (guaranteeing the mass ratio of sodium hydroxide to graphite oxide is 40:1), stirring, evaporating, and drying; (4) The solid obtained after the drying of the step (3) is sintered at 1000 ° C; (5) the solid obtained in the step (4) is washed with water, filtered, and dried to obtain a three-dimensional graphene having a large number of nano-scale micropores on the surface. material.

2、制备二氧化钛 /石墨烯复合材料： 2. Preparation of titanium dioxide/graphene composites:

( 1 )称取 l.Og上述石墨烯材料，加入到 200ml浓硫酸中，搅拌下缓缓加入 20g硝酸钾，室温搅拌反应 5小时的氧化石墨烯材料的溶液；向其中加入 500ml 十二垸基苯磺酸钠水溶液（其中含有 12g十二垸基苯环酸钠和 100g乙醇），滴加过氧化氢直至没有气泡产生，过滤并用去离子水洗涤至中性，干燥得到氧化石墨烯三维衍生材料。将干燥得到的石墨烯三维衍生材料溶于水溶液中，超声得到分散稳定的石墨烯三维衍生材料水溶液。 (1) Weighing 1.0 g of the above graphene material, adding it to 200 ml of concentrated sulfuric acid, slowly adding 20 g of potassium nitrate with stirring, stirring the solution of the graphene oxide material for 5 hours at room temperature; adding 500 ml of the dodecyl group to the solution An aqueous solution of sodium benzenesulfonate (containing 12 g of sodium dodecylbenzene sulfonate and 100 g of ethanol), hydrogen peroxide was added dropwise until no bubbles were generated, filtered and washed with deionized water until neutral, and dried to obtain a graphene oxide three-dimensional derivative material. . The dried graphene three-dimensional derivative material is dissolved in an aqueous solution, and ultrasonically obtained to obtain a dispersion-stabilized graphene three-dimensional derivative material aqueous solution.

(2)按照四氯化钛与氧化石墨烯质量比为 1:3的比例向步骤（1 )得到的悬浮液加入四氯化钛并在 50°C下水解 8h得到悬浮液 b。通过搅拌与超声混合均匀后，将此混合体系在 100°C下进行喷雾干燥手段得到固体粉末。将所得固体粉末在 500°C氩气 /氢气保护下高温煅烧 15h，氧化石墨烯衍生材料被还原成石墨烯衍生材料，得到二氧化钛 /石墨烯复合材料。 (2) The suspension obtained in step (1) according to the ratio of the mass ratio of titanium tetrachloride to graphene oxide of 1:3 The suspension was added with titanium tetrachloride and hydrolyzed at 50 ° C for 8 h to obtain a suspension b. After mixing with ultrasonication by stirring, the mixed system was subjected to spray drying at 100 ° C to obtain a solid powder. The obtained solid powder was calcined at a high temperature for 15 h under an argon/hydrogen protection at 500 ° C, and the graphene oxide-derived material was reduced to a graphene-derived material to obtain a titania/graphene composite material.

2、在恒温条件下，对电池在 0.01V-1.5V电压范围内进行恒流充放电测试，可逆容量高达 447mAh/g，经 500次充放电循环后容量保持 96%。 2. Under constant temperature conditions, the battery is tested for constant current charge and discharge in the voltage range of 0.01V-1.5V. The reversible capacity is up to 447mAh/g, and the capacity is maintained at 96% after 500 charge and discharge cycles.

实施例五 Embodiment 5

( 1 )将氧化石墨置于水中（氧化石墨的浓度为 10mg/mL)，进行超声处理，超声功率 500W, 超声时间 5h，得到氧化石墨悬浮液；（2)配置 10mol/L的氢氧化钠水溶液；（3 ) 将步骤（2) 的氢氧化钠水溶液加入到步骤（1 ) 的氧化石墨悬浮液中（保证氢氧化钠与氧化石墨的质量比为 30:1 )，搅拌，蒸发，干燥；（4) 将步骤（3 ) 干燥后所得到的固体在 1200°C下烧结；（5 ) 将步骤（4) 得到的固体进行水洗、过滤、干燥得到表面含有大量纳米级微孔的三维石墨烯材料。 (1) The graphite oxide is placed in water (the concentration of graphite oxide is 10 mg/mL), sonicated, ultrasonic power is 500 W, ultrasonic time is 5 h, and a graphite oxide suspension is obtained; (2) 10 mol/L sodium hydroxide aqueous solution is disposed. (3) adding the aqueous sodium hydroxide solution of step (2) to the graphite oxide suspension of step (1) (guaranteeing the mass ratio of sodium hydroxide to graphite oxide is 30:1), stirring, evaporating, and drying; 4) The solid obtained by drying step (3) is sintered at 1200 ° C; (5) The solid obtained in step (4) is washed with water, filtered, and dried to obtain a three-dimensional graphene material having a large number of nano-scale micropores on its surface. .

( 1 ) 称取 15g上述石墨烯材料，加入到 15ml浓硫酸中，搅拌下缓缓加入 2.4g铬酸钾，室温搅拌反应 0.5h的氧化石墨烯材料的溶液；向其中加入 50mlPVA 水溶液（其中含有 5gPVA和 3g丙二醇），滴加过氧化氢直至没有气泡产生，过滤并用去离子水洗涤至中性，干燥得到氧化石墨烯三维衍生材料。将干燥得到的石墨烯三维衍生材料溶于水溶液中，超声得到分散稳定的石墨烯三维衍生材料水溶液。 (1) Weigh 15g of the above graphene material, add it to 15ml of concentrated sulfuric acid, slowly add 2.4g of potassium chromate while stirring, stir the solution of the graphene oxide material for 0.5h at room temperature; add 50ml of PVA aqueous solution (including 5 g of PVA and 3 g of propylene glycol), hydrogen peroxide was added dropwise until no bubbles were generated, filtered and washed with deionized water until neutral, and dried to obtain a graphene oxide three-dimensional derivative material. The dried graphene three-dimensional derivative material is dissolved in an aqueous solution, and ultrasonically obtained to obtain a dispersion-stabilized graphene three-dimensional derivative material aqueous solution.

(2)按照四氯化钛与氧化石墨烯 1:8的比例向步骤（1 )得到的悬浮液加入四氯化钛并在 90°C下水解 lh得到悬浮液 b。通过搅拌与超声混合均匀后，将此混合体系经抽滤得到固体粉末。将所得固体粉末在 1100°C氮气 /氢气保护下高温煅烧 4h，氧化石墨烯衍生材料被还原成石墨烯衍生材料，得到二氧化钛 /石墨烯复合材料。 (2) Titanium tetrachloride was added to the suspension obtained in the step (1) in a ratio of titanium tetrachloride to graphene oxide 1:8 and hydrolyzed at 90 ° C for 1 hour to obtain a suspension b. After mixing with ultrasound by stirring, this is The mixed system was suction filtered to give a solid powder. The obtained solid powder was calcined at a high temperature under a nitrogen/hydrogen protection at 1100 ° C for 4 h, and the graphene oxide-derived material was reduced to a graphene-derived material to obtain a titania/graphene composite material.

2、在恒温条件下，对电池在 0.01V-1.5V电压范围内进行恒流充放电测试，可逆容量高达 450mAh/g，经 500次充放电循环后容量保持 95.8%。 2. Under constant temperature conditions, the battery is tested for constant current charge and discharge in the voltage range of 0.01V-1.5V. The reversible capacity is up to 450mAh/g, and the capacity is maintained at 95.8% after 500 charge and discharge cycles.

申请人声明，本发明通过上述实施例来说明本发明的详细工艺设备和工艺流程，但本发明并不局限于上述详细工艺设备和工艺流程，即不意味着本发明必须依赖上述详细工艺设备和工艺流程才能实施。所属技术领域的技术人员应该明了，对本发明的任何改进，对本发明产品各原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本发明的保护范围和公开范围之内。 The Applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention by the above embodiments, but the present invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above detailed process equipment and The process can only be implemented. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitution of the various materials of the products of the present invention, addition of auxiliary components, selection of specific means, and the like, are all within the scope of the present invention.

Claims

权利要求书 claims

1、一种锂离子电池负极用石墨烯复合材料的制备方法，其特征在于，所述方法是将石墨烯类材料在浓酸环境中用氧化剂氧化，超声分散后与钛源混合，经干燥、煅烧后制得； 1. A method for preparing graphene composite materials for lithium-ion battery negative electrodes. The method is characterized in that the method is to oxidize the graphene-based material with an oxidant in a concentrated acid environment, disperse it ultrasonically, mix it with a titanium source, and dry it. Produced after calcination;

所述石墨烯类材料为石墨烯或石墨烯衍生材料；所述钛源为钛源前驱体。 The graphene-based material is graphene or a graphene-derived material; the titanium source is a titanium source precursor.

2、如权利要求 1所述的制备方法，其特征在于，所述石墨烯类材料具有三维结构，且表面有纳米级微孔，其纳米级微孔的孔径在 2nm-100nm范围内，该石墨烯类材料的电导率 1001118/111，比表面积范围为 1500cm²/g-3000cm²/g。 2. The preparation method according to claim 1, characterized in that the graphene material has a three-dimensional structure and has nano-scale micropores on the surface, and the aperture of the nano-scale micropores is in the range of 2nm-100nm, and the graphite The electrical conductivity of vinyl materials is 1001118/111, and the specific surface area ranges from 1500cm ² /g to 3000cm ² /g.

3、如权利要求 1或 2所述的制备方法，其特征在于，所述石墨烯类材料是将热处理或者微波辐照得到的石墨烯粉末与强碱反应，经过后处理制得的。 3. The preparation method according to claim 1 or 2, characterized in that the graphene-based material is obtained by reacting graphene powder obtained by heat treatment or microwave irradiation with a strong alkali and undergoing post-processing.

4、如权利要求 1或 2所述的制备方法，其特征在于，所述钛源前驱体为四氯化钛、钛酸正丁酯、钛酸异丙酯中的 1种，或者几种的组合。 4. The preparation method according to claim 1 or 2, characterized in that the titanium source precursor is one or more of titanium tetrachloride, n-butyl titanate, isopropyl titanate. combination.

5、如权利要求 1-4之一所述的制备方法，其特征在于，所述方法包括如下步骤： 5. The preparation method according to any one of claims 1 to 4, characterized in that the method includes the following steps:

①将石墨烯类材料在浓酸环境中用氧化剂氧化得到氧化石墨烯类材料，经超声分散于分散介质中得悬浮液 a; ① Oxidize graphene-based materials with an oxidant in a concentrated acid environment to obtain graphene oxide materials, and disperse them in a dispersion medium through ultrasonic to obtain suspension a;

②将钛源添加到悬浮液 a中混合均匀，并水解得到悬浮液 b; ② Add titanium source to suspension a, mix evenly, and hydrolyze to obtain suspension b;

③将悬浮液 b搅拌均匀，经抽滤或者喷雾干燥得到块状或者粉末状材料，将块状或者粉末状材料煅烧得到二氧化钛与石墨烯类材料的复合材料，所述二氧化钛为纳米级，其粒径为 10-500nm; ③ Stir the suspension b evenly, obtain a block or powdery material through suction filtration or spray drying, and calcine the block or powdery material to obtain a composite material of titanium dioxide and graphene-like materials. The titanium dioxide is nanoscale, and its particles are Diameter is 10-500nm;

步骤①所述浓酸为浓硫酸、浓硝酸、浓高氯酸、浓磷酸、浓盐酸中的 1种，或者几种的组合；所述分散介质为水，或者水与乙醇、异丙醇、乙二醇中的 1 种的组合，或者水与乙醇、异丙醇、乙二醇中的几种的组合；所述氧化剂为高锰酸钾、硝酸盐、高氯酸盐、过氧化氢、铬酸盐、过硫酸盐中的 1 种，或者几种的组合；所述氧化的时间为 0.5h-5h; The concentrated acid in step ① is one of concentrated sulfuric acid, concentrated nitric acid, concentrated perchloric acid, concentrated phosphoric acid, concentrated hydrochloric acid, or a combination of several; the dispersion medium is water, or water and ethanol, isopropyl alcohol, A combination of one of ethylene glycol, or a combination of water and several of ethanol, isopropyl alcohol, and ethylene glycol; the oxidizing agent is potassium permanganate, nitrate, perchlorate, hydrogen peroxide, One of chromate, persulfate, or several A combination of species; The oxidation time is 0.5h-5h;

步骤②所述悬浮液 b 中，氧化石墨烯类材料的质量百分含量为 0.1wt%-15wt%,钛源和氧化石墨烯类材料的质量比为 1:3-8;所述水解温度为 50 °C-90°C，水解时间为 l-8h_; In the suspension b described in step ②, the mass percentage of the graphene oxide material is 0.1wt%-15wt%, the mass ratio of the titanium source and the graphene oxide material is 1:3-8; the hydrolysis temperature is 50°C-90°C, hydrolysis time is 1-8h _;

步骤③所述喷雾干燥的温度为 100°C-200°C ; 所述煅烧是在氢气和惰性气体中进行的，煅烧温度为 500°C-1200°C，煅烧时间为 4-15h。 The spray drying temperature in step ③ is 100°C-200°C; the calcination is performed in hydrogen and inert gas, the calcination temperature is 500°C-1200°C, and the calcination time is 4-15h.

6、如权利要求 5所述的制备方法，其特征在于，步骤①所述石墨烯类材料具有三维结构，且表面有纳米级微孔，其纳米级微孔的孔径在 2nm-100nm范围内，该石墨烯类材料的电导率 100mS/m，比表面积范围为 1500cm²/g-3000cm²/g; 所述分散介质至少含 20体积％的水； 6. The preparation method according to claim 5, characterized in that the graphene material in step ① has a three-dimensional structure and has nano-scale micropores on the surface, and the pore diameter of the nano-scale micropores is in the range of 2nm-100nm. The electrical conductivity of the graphene-based material is 100mS/m, and the specific surface area ranges from 1500cm ² /g to 3000cm ² /g; the dispersion medium contains at least 20 volume% water;

步骤②所得悬浮液 b 中，氧化石墨烯类材料的质量百分含量为 0.1wt%-10wt%,钛源和氧化石墨烯类材料的质量比为 1:4-6;所述水解温度为 50 °C-70°C，水解时间为 l-6h_; In the suspension b obtained in step ②, the mass percentage of graphene oxide materials is 0.1wt%-10wt%, the mass ratio of titanium source and graphene oxide materials is 1:4-6; the hydrolysis temperature is 50 °C-70°C, hydrolysis time is 1-6h _;

步骤③所述喷雾干燥的温度为 120°C-180°C ; 所述煅烧是在氢气和惰性气体中进行的，煅烧温度为 500°C-1000°C，煅烧时间为 4-8h。 The spray drying temperature in step ③ is 120°C-180°C; the calcination is performed in hydrogen and inert gas, the calcination temperature is 500°C-1000°C, and the calcination time is 4-8h.

7、如权利要求 5或 6所述的制备方法，其特征在于，所述石墨烯类材料是将热处理或者微波辐照得到的石墨烯粉末与强碱反应，经过后处理制得的。 7. The preparation method according to claim 5 or 6, characterized in that the graphene-based material is obtained by reacting graphene powder obtained by heat treatment or microwave irradiation with a strong alkali and undergoing post-processing.

8、如权利要求 5或 6所述的制备方法，其特征在于，步骤③所述煅烧是在氢气和惰性气体中进行的，其惰性气体为氩气，或者为氮气，或者为氩气和氮 8. The preparation method according to claim 5 or 6, characterized in that the calcination in step ③ is carried out in hydrogen and an inert gas, and the inert gas is argon, nitrogen, or argon and nitrogen.

9、如权利要求 5或 6所述的制备方法，其特征在于，步骤②所述悬浮液 b 中有表面活性剂，所述表面活性剂为十二垸基磺酸钠、硬脂酸、 PVA中的 1种，或者几种的组合，表面活性剂在步骤②所述悬浮液 b 中的质量百分含量为 0-5wt%。 9. The preparation method according to claim 5 or 6, characterized in that, the suspension b in step ② contains a surfactant, and the surfactant is sodium dodecyl sulfonate, stearic acid, PVA One of them, or a combination of several, the mass percentage of the surfactant in the suspension b described in step ② is: 0-5wt%.

10、一种按权利要求 1-9之一所述的方法制得的锂离子电池负极用石墨烯复合材料，其特征在于，所述石墨烯复合材料是纳米级二氧化钛与石墨烯类材料的复合材料，具有层状结构，在石墨烯类材料片层之间夹有纳米级二氧化钛粒子，其中石墨烯类材料具有三维结构且表面有纳米级微孔。 10. A graphene composite material for lithium-ion battery negative electrodes prepared according to the method of one of claims 1 to 9, characterized in that the graphene composite material is a composite of nanoscale titanium dioxide and graphene-based materials. The material has a layered structure, with nanoscale titanium dioxide particles sandwiched between the graphene material sheets, where the graphene material has a three-dimensional structure and nanoscale micropores on the surface.