WO2015014120A1

WO2015014120A1 - Negative active material of lithium-ion secondary battery and preparation method therefor, negative plate of lithium-ion secondary battery, and lithium-ion secondary battery

Info

Publication number: WO2015014120A1
Application number: PCT/CN2014/072429
Authority: WO
Inventors: 夏圣安; 杨俊�; 王平华
Original assignee: 华为技术有限公司
Priority date: 2013-07-29
Filing date: 2014-02-24
Publication date: 2015-02-05
Also published as: CN104347858A; CN104347858B

Abstract

An embodiment of the present invention provides a negative active material of a lithium-ion secondary battery. The negative active material of the lithium-ion secondary battery comprises a silicon-based active material and a nitrogen-doped carbon material. The silicon-based active material is loaded on the surface of the nitrogen-doped carbon material. The silicon-based active material is one or more types of the following: nanoparticles and nanowires. The nitrogen-doped carbon material is in a shape of a three-dimensional net, and comprises multiple mutually connected branches. A micropore is disposed on at least one location of the surface and the interior of the nitrogen-doped carbon material. The material of the nitrogen-doped carbon material is a nitrogen-doped carbon net. The negative active material of the lithium-ion secondary battery solves the problem that the volume change of the material is great when a silicon material is used as a negative active material, which makes the material easy to fall off a collector and results in low electric conductivity. Embodiments of the present invention also provide a method for preparing the negative active material of the lithium-ion secondary battery, a lithium-ion secondary battery negative plate containing the negative active material of the lithium-ion secondary battery, and the lithium-ion secondary battery comprising the negative active material of the lithium-ion secondary battery.

Description

锂离子二次电池负极活性材料及其制备方法、锂离子二次电池负极极片和锂离子二次电池 Lithium ion secondary battery anode active material and preparation method thereof, lithium ion secondary battery anode pole piece and lithium ion secondary battery

技术领域 Technical field

本发明涉及锂离子二次电池领域，特别是涉及一种锂离子二次电池负极活性材料及其制备方法、锂离子二次电池负极极片和锂离子二次电池。背景技术 The present invention relates to the field of lithium ion secondary batteries, and in particular to a lithium ion secondary battery anode active material and a preparation method thereof, a lithium ion secondary battery negative electrode sheet and a lithium ion secondary battery. Background technique

随着便携电子设备和电动汽车对能量密度的要求越来越高，高性能锂离子二次电池的研发显得日益重要。 As portable electronic devices and electric vehicles demand higher energy densities, the development of high-performance lithium-ion secondary batteries is becoming increasingly important.

纯硅材料因具有较高的理论容量（高达 4200mAh/g ) 、良好的嵌入 /脱出能力成为了最有前景的一类新型高效储锂负极材料。但是硅材料在脱嵌锂的过程中体积变化超过 300% , 会导致其极易从集流体上脱落，而且硅材料本身电导率较低。目前业界主要采用纳米化、薄膜化、复合化及设计多级特殊结构四种方式来对其进行改性，但效果均不理想，或者是制备过程复杂，难以实现商业化，或者是大量非活性物质的引入极大地消弱了纯硅材料的高容量优势。发明内容 Pure silicon materials have become the most promising class of new high-efficiency lithium storage anode materials due to their high theoretical capacity (up to 4200 mAh/g) and good embedding/release capability. However, the volume change of the silicon material in the process of deintercalating lithium exceeds 300%, which makes it extremely easy to fall off from the current collector, and the silicon material itself has a low electrical conductivity. At present, the industry mainly adopts four methods of nanometering, thinning, compounding and designing multi-stage special structure to modify it, but the effect is not ideal, or the preparation process is complicated, it is difficult to commercialize, or a large amount of inactive The introduction of substances has greatly weakened the high capacity advantages of pure silicon materials. Summary of the invention

有鉴于此，本发明实施例第一方面提供了一种新型的锂离子二次电池负极活性材料，解决了现有技术中硅材料做负极活性材料时体积变化大易从集流体上脱落和电导率低的问题。 In view of this, the first aspect of the embodiments of the present invention provides a novel lithium ion secondary battery anode active material, which solves the problem that the volume change of the silicon material as the anode active material in the prior art is easy to fall off from the current collector and conductance. The problem of low rates.

第一方面，本发明实施例提供了一种锂离子二次电池负极活性材料，包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 In a first aspect, an embodiment of the present invention provides a negative active material for a lithium ion secondary battery, comprising a silicon-based active material and a nitrogen-doped carbon material, wherein the silicon-based active material is supported on the nitrogen-doped carbon material a surface, the silicon-based active material is one or more of a nanoparticle and a nanowire, the silicon-based active material nanoparticle has a particle diameter of 1ηιη~1 μιη, and the nanowire has a diameter of 1 to 200 nm. And the length is 1~10 μιη, the nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material comprises a plurality of cross-linked branches, and the diameter of the branch is 1ηιη~10 μιη, At least one of the surface and the interior of the nitrogen-doped carbon material has micropores, and the material of the nitrogen-doped carbon material is a nitrogen-doped carbon network, and the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are pyridine At least one of a nitrogen type, a graphite type nitrogen, and a pyrrole type nitrogen is combined.

优选地，所述锂离子二次电池负极活性材料中所述硅基活性物质的质量比含量为 0.1%~80%。 Preferably, the mass ratio of the silicon-based active material in the lithium ion secondary battery negative electrode active material is 0.1% to 80%.

优选地，所述氮掺杂的碳材料分支的直径与所述硅基活性物质纳米颗粒的粒径的比例为 1~10:1。 Preferably, the ratio of the diameter of the nitrogen-doped carbon material branch to the particle diameter of the silicon-based active material nanoparticles is from 1 to 10:1.

优选地，所述孔的孔径分布在 0.5~500nm。 Preferably, the pores have a pore size distribution of from 0.5 to 500 nm.

优选地，所述氮掺杂碳网中含有吡咯型氮。氮掺杂碳网中的吡咯型氮可以与 Li⁺结合成键，具有良好的储锂性能。 Preferably, the nitrogen-doped carbon network contains pyrrole-type nitrogen. The pyrrole-type nitrogen in the nitrogen-doped carbon network can be combined with Li ⁺ to form a bond, which has good lithium storage performance.

优选地，所述硅基活性物质的材质选自单质硅、硅氧化物和硅合金中的一种或几种。 Preferably, the material of the silicon-based active material is selected from one or more of elemental silicon, silicon oxide and silicon alloy.

与现有技术相比，本发明实施例第一方面提供了一种锂离子二次电池负极活性材料，硅基活性物质负载在氮掺杂的碳材料表面，硅基活性物质通过氮掺杂的碳材料与集流体结合，氮掺杂的碳材料表面和内部的至少一处具有微孔，氮掺杂的碳材料的微孔能够为硅基活性物质的膨胀预留空间，以及氮掺杂的碳材料呈三维网状，膨胀后的硅基活性物质受到氮掺杂的碳材料的束缚不会脱落，解决了现有技术中硅材料做负极活性材料时体积变化大易从集流体上脱落和电导率低的问题，大大延长了锂离子二次电池负极活性材料的使用寿命，同时氮掺杂碳网能够提高硅基活性物质 /氮掺杂的碳材料复合材料的整体电导率，以及氮掺杂碳网自身具有一定的容量加上硅基活性物质自身的高容量，使得锂离子二次电池负极活性材料具有高容量优势。此外，锂离子二次电池负极活性材料成本较低易于工业化生产。 Compared with the prior art, the first aspect of the present invention provides a lithium ion secondary battery anode active material, wherein the silicon-based active material is supported on the surface of the nitrogen-doped carbon material, and the silicon-based active material is doped by nitrogen. The carbon material is combined with the current collector, and at least one of the surface and the interior of the nitrogen-doped carbon material has micropores, and the micropores of the nitrogen-doped carbon material can reserve space for expansion of the silicon-based active material, and nitrogen-doped The carbon material has a three-dimensional network shape, and the expanded silicon-based active material is not bound by the nitrogen-doped carbon material, which solves the problem that the volume change of the silicon material as the negative electrode active material in the prior art is large and easily falls off from the current collector. The problem of low conductivity greatly extends the service life of the active material of the negative electrode of the lithium ion secondary battery, and the nitrogen-doped carbon network can improve the overall conductivity of the silicon-based active material/nitrogen-doped carbon material composite, and The nitrogen-doped carbon network itself has a certain capacity plus the high capacity of the silicon-based active material itself, so that the lithium ion secondary battery anode active material has a high capacity advantage. In addition, lithium ion secondary batteries have lower anode active materials and are easier to industrially produce.

第二方面，本发明实施例提供了一种锂离子二次电池负极活性材料的制备方法，按以下方法中的一种进行制备： In a second aspect, an embodiment of the present invention provides a method for preparing a negative active material for a lithium ion secondary battery, which is prepared according to one of the following methods:

方法一：通过化学气相沉积法在氮掺杂碳网表面负载硅基活性物质，制得锂离子二次电池负极活性材料； Method 1: The silicon-based active material is loaded on the surface of the nitrogen-doped carbon mesh by chemical vapor deposition to obtain a negative active material for a lithium ion secondary battery;

方法二：通过磁控溅射法在氮掺杂碳网表面负载硅基活性物质，制得锂离子二次电池负极活性材料； Method 2: carrying a silicon-based active material on the surface of the nitrogen-doped carbon mesh by magnetron sputtering to obtain a negative active material for a lithium ion secondary battery;

方法三：将离子液体 3-甲基-丁基吡啶二氰胺盐或 1-乙基 -3-甲基咪唑二氰胺的裂解产物与硅前躯体溶液共混制得混合溶液，所述硅前躯体为 γ -氨丙基三乙氧硅烷、 Υ - ( 2,3-环氧丙氧）丙基三甲氧基硅烷和 γ -甲基丙烯酰氧基丙基三甲氧基硅烷中的一种或几种，将所述混合溶液超声分散后水浴加热，向所述水浴体系中滴入络合剂，随后将含有络合剂的混合溶液搅拌反应，将反应后的产物烘烤后烧结，制得锂离子二次电池负极活性材料； Method 3: mixing a cleavage product of an ionic liquid 3-methyl-butylpyridine dicyanamide salt or 1-ethyl-3-methylimidazolium dicyanamide with a silicon precursor solution to prepare a mixed solution, the silicon The precursor is one of γ-aminopropyltriethoxysilane, Υ-(2,3-epoxypropoxy)propyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane. Or several kinds, the mixed solution is ultrasonically dispersed, heated in a water bath, and the complexing agent is added dropwise to the water bath system, and then the mixed solution containing the complexing agent is stirred and reacted, and the reacted product is baked and sintered. A lithium ion secondary battery anode active material;

所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ m, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。优选地，方法一中所述通过化学气相沉积法在氮掺杂碳网表面负载硅基活性物质为：取氮掺杂碳网置于管式炉内，将管式炉抽真空，按体积比为 1:0.1~10 的比例通入硅源 SiH₄和保护性气体，控制气流量为 30~300 sccm,以 l~50°C/min 的升温速率将管式炉内升温至 500~1300°C并保温 3~60min, 随后冷却至室温，制得锂离子二次电池负极活性材料。 The lithium ion secondary battery anode active material includes a silicon-based active material and a nitrogen-doped carbon material, the silicon-based active material is supported on a surface of the nitrogen-doped carbon material, and the silicon-based active material is a nanoparticle And one or more of the nanowires, the silicon-based active material nanoparticles have a particle diameter of 1 ηηη~1 μιη, and the nanowires have a diameter of 1 to 200 nm and a length of 1 to 10 μιη, The nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the branches having a diameter of 1 ηηη to 10 μm, and the surface and interior of the nitrogen-doped carbon material At least one of the micropores has a material of a nitrogen-doped carbon material, wherein the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are in a pyridine type nitrogen, a graphite type nitrogen, and a pyrrole type nitrogen. At least one form of combination. Preferably, the method for loading the silicon-based active material on the surface of the nitrogen-doped carbon mesh by chemical vapor deposition is as follows: the nitrogen-doped carbon mesh is placed in a tube furnace, and the tube furnace is evacuated according to a volume ratio. The silicon source SiH ₄ and the protective gas are introduced at a ratio of 1:0.1~10, the gas flow rate is controlled to 30~300 sccm, and the temperature in the tube furnace is raised to 500~1300° at a heating rate of l~50 °C/min. C is kept for 3 to 60 minutes, and then cooled to room temperature to obtain a lithium ion secondary battery negative active material.

优选地，方法二中所述通过磁控溅射法在氮掺杂碳网表面负载硅基活性物质为：取氮掺杂碳网置于磁控溅射腔体，装上硅靶，抽真空至 0~10-²Pa, 通入气流量为 10~300sccm的保护性气体至磁控溅射腔体内压强为 l~10Pa, 控制功率为 10-200W, 在 100~400°C溅射 l~10min, 随后冷却至室温，制得锂离子二次电池负极活性材料。 Preferably, in the method 2, the silicon-based active material is supported on the surface of the nitrogen-doped carbon mesh by magnetron sputtering: the nitrogen-doped carbon mesh is placed in the magnetron sputtering chamber, the silicon target is mounted, and the vacuum is applied. to 0 ~ 10- ² Pa, gas flow is introduced into 10 ~ 300sccm protective gas into the body cavity magnetron sputtering pressure of l ~ 10Pa, the control power is 10-200W, sputtering l at 100 ~ 400 ° C ~ After 10 minutes, it was cooled to room temperature to prepare a lithium ion secondary battery negative electrode active material.

优选地，方法三中所述离子液体裂解产物与所述硅前躯体的质量比为 1:0.1-5 , 所述络合剂为柠檬酸、酒石酸、 EDTA和丁二酸钠的一种或几种，将含有络合剂的混合溶液恒温 50~100 °C搅拌下反应 0.5~5h , 将反应后的产物于 50~100 °C真空下烘烤 l~24h , 再转入气氛烧结炉中，在保护性气体氛围下 500~1300°C烧结 l~10h, 随后冷却至室温。 Preferably, the mass ratio of the ionic liquid cleavage product to the silicon precursor in the third method is 1:0.1-5, and the complexing agent is one or several of citric acid, tartaric acid, EDTA and sodium succinate. a mixture solution containing a complexing agent is heated at a temperature of 50 to 100 ° C for 0.5 to 5 hours, and the product after the reaction is baked at 50 to 100 ° C for 1 to 24 hours under vacuum, and then transferred to an atmosphere sintering furnace. Sintered at 500~1300 °C for 1~10h in a protective gas atmosphere, then cooled to room temperature.

本发明实施例第二方面提供的一种锂离子二次电池负极活性材料的制备方法工艺筒单方便，成本低，易于工业化生产。 The method for preparing a negative electrode active material for a lithium ion secondary battery provided by the second aspect of the present invention is convenient, low in cost, and easy to industrialize.

第三方面，本发明实施例提供了一种锂离子二次电池负极极片，所述锂离子二次电池负极极片包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη,所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 In a third aspect, an embodiment of the present invention provides a negative electrode tab for a lithium ion secondary battery, wherein the negative electrode tab of the lithium ion secondary battery includes a silicon-based active material and a nitrogen-doped carbon material, and the silicon-based active material Loading on the surface of the nitrogen-doped carbon material, the silicon-based active material is one or more of a nanoparticle and a nanowire, and the particle diameter of the silicon-based active material nanoparticle is 1ηιη~1 μ ιη, The nanowire has a diameter of 1 to 200 nm and a length of 1 to 10 μm. The nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the branch. The diameter is 1ηιη~10 μιη, the nitrogen-doped At least one of the surface and the inner portion of the carbon material has micropores, and the material of the nitrogen-doped carbon material is a nitrogen-doped carbon network, and the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are pyridine type nitrogen and graphite type. At least one of nitrogen and pyrrole type nitrogen is combined.

本发明实施例第三方面提供的一种锂离子二次电池负极极片使用寿命长且电导率良好。 A lithium ion secondary battery negative electrode pole piece provided by the third aspect of the present invention has a long service life and good electrical conductivity.

第四方面，本发明实施例提供了一种锂离子二次电池，所述锂离子二次电池由锂离子二次电池负极极片、正极极片、隔膜、非水电解液和外壳组成，所述锂离子二次电池负极极片包括集流体和涂覆在所述集流体上的锂离子二次电池负极活性材料，所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 In a fourth aspect, an embodiment of the present invention provides a lithium ion secondary battery, which is composed of a lithium ion secondary battery negative electrode pole piece, a positive electrode pole piece, a separator, a non-aqueous electrolyte, and an outer casing. The lithium ion secondary battery negative electrode tab includes a current collector and a lithium ion secondary battery anode active material coated on the current collector, the lithium ion secondary battery anode active material including a silicon-based active material and nitrogen doping a carbon material, the silicon-based active material is supported on a surface of the nitrogen-doped carbon material, and the silicon-based active material is one or more of a nanoparticle and a nanowire, and the silicon-based active material nanoparticle The particle diameter is 1ηιη~1 μιη, the nanowire has a diameter of 1 to 200 nm and a length of 1 to 10 μm, and the nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of a branch of the root cross-linking, the branch having a diameter of 1 ηηη to 10 μιη, the nitrogen-doped carbon material having micropores in at least one of the surface and the inside thereof, and the nitrogen-doped carbon material is made of nitrogen Doped carbon network, said Network carbon doped with nitrogen atoms in at least one carbon atom of nitrogen form pyridine type, graphite type and nitrogen in the pyrrole nitrogen type.

本发明实施例第四方面提供的锂离子二次电池使用寿命长且电导率良好。本发明实施例第一方面提供了一种锂离子二次电池负极活性材料，硅基活性物质负载在氮掺杂的碳材料表面，硅基活性物质通过氮掺杂的碳材料与集流体结合，氮掺杂的碳材料表面和内部的至少一处具有微孔，氮掺杂的碳材料的微孔能够为硅基活性物质的膨胀预留空间，以及氮掺杂的碳材料呈三维网状，膨胀后的硅基活性物质受到氮掺杂的碳材料的束缚不会脱落，解决了现有技术中硅材料做负极活性材料时体积变化大易从集流体上脱落和电导率低的问题，大大延长了锂离子二次电池负极活性材料的使用寿命，同时氮掺杂碳网能够提高硅基活性物质 /氮掺杂的碳材料复合材料的整体电导率，以及氮掺杂碳网自身具有一定的容量加上硅基活性物质自身的高容量，使得锂离子二次电池负极活性材料具有高容量优势。此外，锂离子二次电池负极活性材料成本较低易于工业化生产。本发明实施例第二方面提供的一种锂离子二次电池负极活性材料的制备方法工艺筒单方便，成本低，易于工业化生产。本发明实施例第三方面提供的一种锂离子二次电池负极极片和第四方面提供的锂离子二次电池使用寿命长且电导率良好。本发明实施例的优点将会在下面的说明书中部分阐明，一部分根据说明书是显而易见的，或者可以通过本发明实施例的实施而获知。附图说明图 1为本发明实施例一制得的锂离子二次电池负极活性材料的 SEM电镜图。图 2为本发明实施例二制得的锂离子二次电池负极活性材料中氮掺杂碳网的结构示意图。具体实施方式以下所述是本发明实施例的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明实施例原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本发明实施例的保护范围。本发明实施例第一方面提供了一种新型的锂离子二次电池负极活性材料，解决了现有技术中硅材料做负极活性材料时体积变化大易从集流体上脱落和电导率低的问题。本发明实施例第二方面提供了所述锂离子二次电池负极活性材料的制备方法，工艺筒单方便，成本低，易于工业化生产。本发明实施例第三方面提供了包含所述锂离子二次电池负极活性材料的锂离子二次电池负极极片，以及本发明实施例第四方面提供了包含所述锂离子二次电池负极活性材料的锂离子二次电池。 The lithium ion secondary battery provided by the fourth aspect of the embodiment of the present invention has a long service life and good electrical conductivity. A first aspect of the present invention provides a negative active material for a lithium ion secondary battery. The silicon-based active material is supported on the surface of the nitrogen-doped carbon material, and the silicon-based active material is combined with the current collector through the nitrogen-doped carbon material. At least one of the surface and the interior of the nitrogen-doped carbon material has micropores, the pores of the nitrogen-doped carbon material can reserve space for expansion of the silicon-based active material, and the nitrogen-doped carbon material has a three-dimensional network. The expanded silicon-based active material is not bound by the nitrogen-doped carbon material, which solves the problem that the volume change of the silicon material as the negative electrode active material in the prior art is easy to fall off from the current collector and the conductivity is low. The service life of the negative active material of the lithium ion secondary battery is greatly extended, and the nitrogen-doped carbon network can improve the overall conductivity of the silicon-based active material/nitrogen-doped carbon material composite material, and the nitrogen-doped carbon network itself has certain The capacity of the silicon-based active material itself and the high capacity of the silicon-based active material make the lithium ion secondary battery negative active material have a high capacity advantage. In addition, lithium ion secondary batteries have lower anode active materials and are easier to industrially produce. The method for preparing a negative electrode active material for a lithium ion secondary battery provided by the second aspect of the present invention is convenient in process, low in cost, and easy to industrialize. A lithium ion secondary battery negative electrode tab provided by the third aspect of the present invention and a lithium ion secondary battery provided by the fourth aspect have a long service life and good electrical conductivity. The advantages of the embodiments of the present invention will be set forth in part in the description which follows. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a SEM electron micrograph of a negative active material of a lithium ion secondary battery produced in Example 1 of the present invention. 2 is a schematic structural view of a nitrogen-doped carbon mesh in a negative active material of a lithium ion secondary battery prepared in Example 2 of the present invention. The following is a preferred embodiment of the embodiments of the present invention, and it should be noted that those skilled in the art can make some improvements and retouching without departing from the principles of the embodiments of the present invention. These improvements and retouchings are also considered to be the scope of protection of the embodiments of the present invention. The first aspect of the present invention provides a novel lithium ion secondary battery anode active material, which solves the problem that the volume change of the silicon material as the anode active material is easy to fall off from the current collector and the conductivity is low in the prior art. . A second aspect of the present invention provides a method for preparing a negative active material of the lithium ion secondary battery, which is convenient in process, low in cost, and easy to industrialize. Third party of the embodiment of the invention Provided is a lithium ion secondary battery negative electrode sheet comprising the lithium ion secondary battery negative electrode active material, and a fourth aspect of the present invention provides lithium ion secondary material including the lithium ion secondary battery negative electrode active material battery.

优选地，所述锂离子二次电池负极活性材料中所述硅基活性物质的质量比含量为 0.1%~80%。更优选地，所述锂离子二次电池负极活性材料中所述硅基活性物质的质量比含量为 5%~50%。进一步优选地，所述锂离子二次电池负极活性材料中所述硅基活性物质的质量比含量为 15%~30%。 Preferably, the mass ratio of the silicon-based active material in the lithium ion secondary battery negative electrode active material is 0.1% to 80%. More preferably, the lithium ion secondary battery negative active material has a mass ratio of the silicon-based active material of 5% to 50%. Further preferably, the lithium ion secondary battery negative electrode active material has a mass ratio of the silicon-based active material of 15% to 30%.

优选地，所述氮掺杂的碳材料分支的直径为 30ηιη~5 μ ιη。 Preferably, the nitrogen-doped carbon material has a diameter of 30 η η η to 5 μ ηη.

优选地，所述微孔的孔径分布在 0.5~500nm。更优选地，所述微孔的孔径分布在 2~100nm。 Preferably, the pores of the micropores are distributed between 0.5 and 500 nm. More preferably, the pores of the micropores are distributed at 2 to 100 nm.

氮掺杂的碳材料表面或内部具有微孔结构，或者在氮掺杂的碳材料表面和内部具有微孔结构。 The nitrogen-doped carbon material has a microporous structure on the surface or inside, or has a microporous structure on the surface and inside of the nitrogen-doped carbon material.

优选地，所述氮掺杂碳网中含有吡咯型氮。氮掺杂碳网中的吡咯型氮可以与 Li⁺结合成键，具有良好的储锂性能。 Preferably, the nitrogen-doped carbon network contains pyrrole-type nitrogen. Pyrrole-type nitrogen in nitrogen-doped carbon networks can be Li ⁺ combines into a bond and has good lithium storage properties.

优选地，所述硅基活性物质纳米颗粒的粒径为 30nm~200nm。 Preferably, the silicon-based active material nanoparticles have a particle diameter of 30 nm to 200 nm.

优选地，所述硅基活性物质的纳米线和纳米棒的直径为 10~100nm且长度为 2-5 μ m。 Preferably, the nanowires and nanorods of the silicon-based active material have a diameter of 10 to 100 nm and a length of 2 to 5 μm.

本发明实施例第一方面提供了一种锂离子二次电池负极活性材料，硅基活性物质负载在氮掺杂的碳材料表面，硅基活性物质通过氮掺杂的碳材料与集流体结合，氮掺杂的碳材料表面和内部的至少一处具有微孔，氮掺杂的碳材料的微孔能够为硅基活性物质的膨胀预留空间，以及氮掺杂的碳材料呈三维网状，膨胀后的硅基活性物质受到氮掺杂的碳材料的束缚不会脱落，解决了现有技术中硅材料做负极活性材料时体积变化大易从集流体上脱落和电导率低的问题，大大延长了锂离子二次电池负极活性材料的使用寿命，同时氮掺杂碳网能够提高硅基活性物质 /氮掺杂的碳材料复合材料的整体电导率，以及氮掺杂碳网自身具有一定的容量加上硅基活性物质自身的高容量，使得锂离子二次电池负极活性材料具有高容量优势。此外，锂离子二次电池负极活性材料成本较低易于工业化生产。 A first aspect of the present invention provides a negative active material for a lithium ion secondary battery. The silicon-based active material is supported on the surface of the nitrogen-doped carbon material, and the silicon-based active material is combined with the current collector through the nitrogen-doped carbon material. At least one of the surface and the interior of the nitrogen-doped carbon material has micropores, the pores of the nitrogen-doped carbon material can reserve space for expansion of the silicon-based active material, and the nitrogen-doped carbon material has a three-dimensional network. The expanded silicon-based active material is not bound by the nitrogen-doped carbon material, which solves the problem that the volume change of the silicon material as the negative electrode active material in the prior art is easy to fall off from the current collector and the conductivity is low. The service life of the negative active material of the lithium ion secondary battery is prolonged, and the nitrogen-doped carbon network can improve the overall conductivity of the silicon-based active material/nitrogen-doped carbon material composite material, and the nitrogen-doped carbon network itself has certain The capacity plus the high capacity of the silicon-based active material itself makes the lithium ion secondary battery negative active material have a high capacity advantage. In addition, lithium ion secondary batteries have lower anode active materials and are easier to industrially produce.

方法二：通过磁控溅射法在氮掺杂碳网表面负载硅基活性物质，制得锂离子二次电池负极活性材料；方法三：将离子液体 3-甲基-丁基吡啶二氰胺盐或 1-乙基 -3-甲基咪唑二氰胺的裂解产物与硅前躯体溶液共混制得混合溶液，所述硅前躯体为 γ -氨丙基三乙氧硅烷、 Υ - ( 2,3-环氧丙氧）丙基三甲氧基硅烷和 γ -甲基丙烯酰氧基丙基三甲氧基硅烷中的一种或几种，将所述混合溶液超声分散后水浴加热，向所述水浴体系中滴入络合剂，随后将含有络合剂的混合溶液搅拌反应，将反应后的产物烘烤后烧结，制得锂离子二次电池负极活性材料； Method 2: loading a silicon-based active material on the surface of the nitrogen-doped carbon mesh by magnetron sputtering to obtain a negative active material for a lithium ion secondary battery; Method 3: mixing a cleavage product of an ionic liquid 3-methyl-butylpyridine dicyanamide salt or 1-ethyl-3-methylimidazolium dicyanamide with a silicon precursor solution to prepare a mixed solution, the silicon The precursor is one of γ-aminopropyltriethoxysilane, Υ-(2,3-epoxypropoxy)propyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane. Or several kinds, the mixed solution is ultrasonically dispersed, heated in a water bath, and the complexing agent is added dropwise to the water bath system, and then the mixed solution containing the complexing agent is stirred and reacted, and the reacted product is baked and sintered. A lithium ion secondary battery anode active material;

所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ m, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 The lithium ion secondary battery anode active material includes a silicon-based active material and a nitrogen-doped carbon material, the silicon-based active material is supported on a surface of the nitrogen-doped carbon material, and the silicon-based active material is a nanoparticle And one or more of the nanowires, the silicon-based active material nanoparticles have a particle diameter of 1 ηηη~1 μιη, and the nanowires have a diameter of 1 to 200 nm and a length of 1 to 10 μιη, The nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the branches having a diameter of 1 ηηη to 10 μm, and the surface and interior of the nitrogen-doped carbon material At least one of the micropores has a material of a nitrogen-doped carbon material, wherein the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are in a pyridine type nitrogen, a graphite type nitrogen, and a pyrrole type nitrogen. At least one form of combination.

优选地，方法一中所述通过化学气相沉积法在氮掺杂碳网表面负载硅基活性物质为：取氮掺杂碳网置于管式炉内，将管式炉抽真空，按体积比为 1:0.1~10 的比例通入硅源 SiH₄和保护性气体，控制气流量为 30~300 sccm,以 l~50°C/min 的升温速率将管式炉内升温至 500~1300°C并保温 3~60min, 随后冷却至室温，制得锂离子二次电池负极活性材料。取氮掺杂碳网置于石英管中，将管式炉抽真空，按体积比为 1:0.1~10的比例通入硅源 SiH₄和保护性气体，控制气流量为 30-300 sccm, 以 l~50°C/min的升温速率将管式炉内升温至 500~1300°C并保温 3~60min, 随后冷却至室温，制得锂离子二次电池负极活性材料。 Preferably, in the first method, the silicon-based active material is supported on the surface of the nitrogen-doped carbon mesh by chemical vapor deposition: the nitrogen-doped carbon mesh is placed in the tube furnace, and the tube furnace is evacuated according to the volume ratio. The silicon source SiH ₄ and the protective gas are introduced at a ratio of 1:0.1~10, the gas flow rate is controlled to 30~300 sccm, and the temperature in the tube furnace is raised to 500~1300° at a heating rate of l~50 °C/min. C is kept for 3 to 60 minutes, and then cooled to room temperature to obtain a lithium ion secondary battery negative active material. The nitrogen-doped carbon network is placed in a quartz tube, and the tube furnace is evacuated, and the silicon source SiH ₄ and the protective gas are introduced at a volume ratio of 1:0.1 to 10, and the controlled gas flow rate is 30-300 sccm. The temperature of the tube furnace was raised to 500~1300 °C at a heating rate of l~50 °C/min and the temperature was maintained for 3 to 60 minutes, and then cooled to room temperature to prepare a negative active material for the lithium ion secondary battery.

优选地，方法二中所述通过磁控溅射法在氮掺杂碳网表面负载硅基活性物质为：取氮掺杂碳网置于磁控溅射腔体，装上硅靶，抽真空至 0~10-²Pa, 通入气流量为 10~300sccm的保护性气体至磁控溅射腔体内压强为 l~10Pa, 控制功率为 10-200W, 在 100~400°C溅射 l~10min, 随后冷却至室温，制得锂离子二次电池负极活性材料。取氮掺杂碳网置于磁控溅射腔体，装上硅靶，抽真空至 0~10-²Pa, 通入气流量为 10~300sccm的保护性气体至磁控溅射腔体内压强为 l~10Pa,控制功率为 10~200W, 在 100~400°C溅射 l~10min, 随后冷却至室温，制得锂离子二次电池负极活性材料。 Preferably, the silicon-based active material is supported on the surface of the nitrogen-doped carbon mesh by magnetron sputtering as described in the second method. : Taking nitrogen-doped carbon mesh is placed a magnetron sputtering chamber, fitted with a silicon target, evacuated to 0 ~ 10- ² Pa, gas flow is introduced into 10 ~ 300sccm protective gas to the sputtering chamber The internal pressure is l~10Pa, the control power is 10-200W, sputtering is performed at 100~400 °C for l~10min, and then cooled to room temperature to obtain a negative active material for lithium ion secondary battery. Nitrogen-doped carbon network takes place magnetron sputtering chamber by magnetron sputtering pressure chamber, fitted with a silicon target, evacuated to 0 ~ 10- ² Pa, gas flow into the protective gas to 10 ~ 300sccm For l~10Pa, the control power is 10~200W, sputtering at 100~400°C for l~10min, and then cooled to room temperature to obtain the negative active material of lithium ion secondary battery.

优选地，方法三中所述离子液体裂解产物与所述硅前躯体的质量比为 1:0.1-5 , 所述络合剂为柠檬酸、酒石酸、 EDTA和丁二酸钠的一种或几种，将含有络合剂的混合溶液恒温 50~100 °C搅拌下反应 0.5~5h , 将反应后的产物于 50~100 °C真空下烘烤 l~24h , 再转入气氛烧结炉中，在保护性气体氛围下 500~1300°C烧结 l~10h, 随后冷却至室温。取离子液体 3-甲基-丁基吡啶二氰胺盐或 1-乙基 -3-甲基咪唑二氰胺置于陶瓷坩埚中，转入管式炉内，通入保护性气体，以 l~10°C/min的升温速率将管式炉内升温至 400~800°C并保温 l~10h, 随后冷却至室温，制得离子液体裂解产物；随后将所述离子液体裂解产物与硅前躯体溶液共混制得混合溶液，所述硅前躯体为 γ -氨丙基三乙氧硅烷、 γ - ( 2,3- 环氧丙氧 ) 丙基三甲氧基硅烷和 γ -甲基丙烯酰氧基丙基三甲氧基硅烷中的一种或几种，所述离子液体裂解产物与所述硅前 ^区体的质量比为 1:0.1~5；将所述混合溶液超声分散 5~60min, 随后置于容器中水浴加热至 50~100°C , 向所述容器中滴入络合剂，所述络合剂为柠檬酸、酒石酸、 EDTA和丁二酸钠的一种或几种，随后将含有络合剂的混合溶液恒温 50~100°C搅拌下反应 0.5~5h, 将反应后的产物于 50~100°C真空下烘烤 l~24h, 再转入气氛烧结炉中，在保护性气体氛围下 500~1300°C烧结 l~10h, 随后冷却至室温，制得锂离子二次电池负极活性材料。更优选地，氮掺杂碳网通过以下方式得到：聚吡啶、聚吡咯、聚苯胺及其衍生物中的一种或几种的高温分解、苯胺、吡咯、吡啶及其衍生物中的一种或几种的化学气相沉积或离子液体 3-甲基-丁基吡啶二氰胺盐和 1-乙基 -3-甲基咪唑二氰胺及其衍生物中的一种或几种的高温分解。有机分子作为碳源，在高温过程中形成氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。以及，在高温分解过程中，有机分子分解出小分子气体，小分子气体从氮掺杂的碳材料表面逸出，从而在氮掺杂的碳材料表面或内部形成微孔结构，或者在氮掺杂的碳材料表面和内部形成微孔结构。 Preferably, the mass ratio of the ionic liquid cleavage product to the silicon precursor in the third method is 1:0.1-5, and the complexing agent is one or several of citric acid, tartaric acid, EDTA and sodium succinate. a mixture solution containing a complexing agent is heated at a temperature of 50 to 100 ° C for 0.5 to 5 hours, and the product after the reaction is baked at 50 to 100 ° C for 1 to 24 hours under vacuum, and then transferred to an atmosphere sintering furnace. Sintered at 500~1300 °C for 1~10h in a protective gas atmosphere, then cooled to room temperature. Take the ionic liquid 3-methyl-butyl dicyandiamide or 1-ethyl-3-methylimidazolium dicyanamide in a ceramic crucible, transfer it into a tube furnace, and pass a protective gas to The temperature rise rate of ~10 ° C / min will be heated to 400 ~ 800 ° C in the tube furnace and kept for l ~ 10h, and then cooled to room temperature, to obtain ionic liquid cleavage products; then the ionic liquid cleavage products and silicon front The body solution is blended to prepare a mixed solution, and the silicon precursor is γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and γ-methacryloyl group. One or more of oxypropyltrimethoxysilane, the mass ratio of the ionic liquid cleavage product to the silicon front region is 1:0.1-5; the mixed solution is ultrasonically dispersed for 5~60 min Then, it is heated in a water bath to 50 to 100 ° C in a container, and a complexing agent is added to the container, and the complexing agent is one or more of citric acid, tartaric acid, EDTA and sodium succinate. Subsequently, the mixed solution containing the complexing agent is heated at a constant temperature of 50 to 100 ° C for 0.5 to 5 hours, and the product after the reaction is baked at 50 to 100 ° C for 1 to 24 hours under vacuum, and then transferred to an atmosphere for burning. Furnace, under a protective gas atmosphere at 500 ~ 1300 ° C sintering l ~ 10h, then cooled to room temperature to prepare a lithium ion secondary battery negative electrode active material. More preferably, the nitrogen-doped carbon network is obtained by: pyrolysis of one or more of polypyridine, polypyrrole, polyaniline and derivatives thereof, one of aniline, pyrrole, pyridine and derivatives thereof Pyrolysis of one or more of chemical vapor deposition or ionic liquids 3-methyl-butylpyridine dicyanamide salt and 1-ethyl-3-methylimidazolium dicyanamide and its derivatives . The organic molecule acts as a carbon source to form a nitrogen-doped carbon network in a high temperature process, wherein the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are combined in at least one of a pyridine type nitrogen, a graphite type nitrogen, and a pyrrole type nitrogen. And, in the pyrolysis process, the organic molecules decompose out a small molecule gas, and the small molecule gas escapes from the surface of the nitrogen-doped carbon material, thereby forming a microporous structure on the surface or inside of the nitrogen-doped carbon material, or in nitrogen doping The surface and interior of the hybrid carbon material form a microporous structure.

进一步优选地，所述氮掺杂碳网按如下方法之一制备： Further preferably, the nitrogen-doped carbon network is prepared in one of the following ways:

聚吡啶、聚吡咯、聚苯胺及其衍生物中的一种或几种的高温分解法：将十六烷基三甲基溴化铵（ CTAB, (C₁₆H₃₃ )N(CH₃)₃Br, 7.3 g )溶解在冰水浴的 HC1( 120 mL, 1 mol/L )溶液中，超声分散均匀，然后将过硫酸铵 ( APS, 13.7 g )加入其中，立刻形成白色的悬浊液，搅拌 0.5小时后，再加入吡咯单体（Py, 8.3 mL ),在 4。C 下保温反应 24 h后过滤，将得到的黑色沉淀物用 1 mol/L的 HC1溶液洗涤三次，再用纯净水洗涤至溶液呈无色中性，接着把沉淀物在 80。C下干燥 24小时，最后将干燥后的沉淀物放置在管式炉中，通入 5 % H₂/Ar混合气，在 700。C下烧结得 2小时即可得到氮掺杂碳网；或 Pyrolysis of one or more of polypyridine, polypyrrole, polyaniline and its derivatives: cetyltrimethylammonium bromide (CTAB, (C ₁₆ H ₃₃ )N(CH ₃ ) ₃ Br, 7.3 g) dissolved in an ice water bath of HC1 (120 mL, 1 mol/L) solution, dispersed evenly by ultrasound, then added ammonium persulfate (APS, 13.7 g) to it, immediately forming a white suspension, stirring After 0.5 hours, additional pyrrole monomer (Py, 8.3 mL) was added at 4. After incubation for 24 hours, the mixture was filtered, and the obtained black precipitate was washed three times with a 1 mol/L HCl solution, and then washed with purified water until the solution was colorless neutral, and then the precipitate was at 80. Drying was carried out for 24 hours at C, and finally the dried precipitate was placed in a tube furnace, and a mixture of 5% H ₂ /Ar was introduced at 700. Nitrogen-doped carbon mesh can be obtained by sintering at C for 2 hours; or

苯胺、吡咯、吡啶及其衍生物中的一种或几种的化学气相沉积法：将管式炉抽真空，用 Ar 负载气化的吡啶单体（pyridine )做反应气， Ar 气流量控制为 50ml/min, 升降温速度 30°C/min, 700°C下保温 6小时，待管式炉冷却至室温，得到氮掺杂碳网；或 Chemical vapor deposition of one or more of aniline, pyrrole, pyridine and its derivatives: The tube furnace is evacuated, and the Ar gas-loaded pyridine monomer (pyridine) is used as the reaction gas, and the Ar gas flow rate is controlled. 50ml/min, the temperature rise and fall is 30°C/min, and the temperature is kept at 700°C for 6 hours. The tube furnace is cooled to room temperature to obtain a nitrogen-doped carbon mesh; or

离子液体 3-甲基-丁基吡啶二氰胺盐和 1-乙基 -3-甲基咪唑二氰胺及其衍生物中的一种或几种的高温分解法：取离子液体 3-甲基-丁基吡啶二氰胺盐置于氧化铝坩埚中，转入管式炉内，通入保护性气体，以 2°C/min的升温速率将管式炉内升温至 600°C并保温 2h, 随后冷却至室温，制得离子液体裂解产物；随后将所述离子液体裂解产物转入气氛烧结炉中，通入还原气氛，将烘烤后的产物在 500 °C温度下烧结 4h, 随后冷却至室温，得到氮掺杂碳网。 Pyrolysis of one or more of ionic liquids 3-methyl-butylpyridine dicyanamide salt and 1-ethyl-3-methylimidazolium dicyanamide and its derivatives: ionic liquid 3-methyl Base-butyl pyridine dicyanamide salt is placed in oxidation In the aluminum crucible, transfer into the tube furnace, pass protective gas, raise the temperature in the tube furnace to 600 ° C at 2 ° C / min and keep it for 2 h, then cool to room temperature to obtain ionic liquid cracking. The product; the ionic liquid cracking product is then transferred to an atmosphere sintering furnace, passed to a reducing atmosphere, and the baked product is sintered at a temperature of 500 ° C for 4 hours, followed by cooling to room temperature to obtain a nitrogen-doped carbon network.

优选地，所述氮掺杂碳网中含有吡咯型氮。氮掺杂碳网中的吡咯型氮可以与 Preferably, the nitrogen-doped carbon network contains pyrrole-type nitrogen. Pyrrole-type nitrogen in nitrogen-doped carbon networks can be

Li⁺结合成键，具有良好的储锂性能。 Li ⁺ combines into a bond and has good lithium storage properties.

本发明实施例第二方面提供的一种锂离子二次电池负极活性材料的制备方法工艺筒单方便，成本低，易于工业化生产。 Preparation method of negative electrode active material for lithium ion secondary battery provided by second aspect of embodiment of the present invention The process cartridge is simple, low in cost and easy to industrialize.

第三方面，本发明实施例提供了一种锂离子二次电池负极极片，所述锂离子二次电池负极极片包括集流体和涂覆在所述集流体上的锂离子二次电池负极活性材料，所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 lnm~l μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 In a third aspect, an embodiment of the present invention provides a negative electrode tab for a lithium ion secondary battery, the negative electrode tab of the lithium ion secondary battery including a current collector and a lithium ion secondary battery negative electrode coated on the current collector An active material, the lithium ion secondary battery anode active material includes a silicon-based active material and a nitrogen-doped carbon material, and the silicon-based active material is supported on a surface of the nitrogen-doped carbon material, the silicon-based active material The nano-particles and the nanowires have a particle diameter of 1 nm to 1 μm, and the nanowires have a diameter of 1 to 200 nm and a length of 1 to 10 μm. The nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of mutually cross-linked branches, and the branches have a diameter of 1 ηηη to 10 μιη, and the nitrogen-doped carbon material surface And at least one of the interior has micropores, the nitrogen-doped carbon material is made of a nitrogen-doped carbon network, and the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are pyridine type nitrogen, graphite type nitrogen and pyrrole At least one of the forms of nitrogen binds.

本发明实施例第三方面提供的一种锂离子二次电池负极极片使用寿命长且电导率良好。其中所述锂离子二次电池负极活性材料的优选方式同第一方面。 A lithium ion secondary battery negative electrode pole piece provided by the third aspect of the present invention has a long service life and good electrical conductivity. The preferred mode of the lithium ion secondary battery negative electrode active material is the same as the first aspect.

第四方面，本发明实施例提供了一种锂离子二次电池，所述锂离子二次电池由锂离子二次电池负极极片、正极极片、隔膜、非水电解液和外壳组成，所述锂离子二次电池负极极片包括集流体和涂覆在所述集流体上的锂离子二次电池负极活性材料，所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 In a fourth aspect, an embodiment of the present invention provides a lithium ion secondary battery, which is composed of a lithium ion secondary battery negative electrode pole piece, a positive electrode pole piece, a separator, a non-aqueous electrolyte, and an outer casing. The lithium ion secondary battery negative electrode tab includes a current collector and a lithium ion secondary battery anode active material coated on the current collector, the lithium ion secondary battery anode active material including a silicon-based active material and nitrogen doping a carbon material, the silicon-based active material is supported on a surface of the nitrogen-doped carbon material, and the silicon-based active material is one or more of a nanoparticle and a nanowire, and the silicon-based active material nanoparticle The particle diameter is 1ηιη~1 μιη, the nanowire has a diameter of 1 to 200 nm and a length of 1 to 10 μm, and the nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of a branch of the root cross-linking, the branch having a diameter of 1 ηηη to 10 μιη, the nitrogen-doped carbon material having micropores in at least one of the surface and the inside thereof, and the nitrogen-doped carbon material is made of nitrogen Doped carbon network, the nitrogen-doped carbon Nitrogen atoms to carbon atoms It is combined in the form of at least one of a pyridine type nitrogen, a graphite type nitrogen, and a pyrrole type nitrogen.

本发明实施例第四方面提供的锂离子二次电池使用寿命长且电导率良好。其中所述锂离子二次电池负极活性材料的优选方式同第一方面。 The lithium ion secondary battery provided by the fourth aspect of the embodiment of the present invention has a long service life and good electrical conductivity. The preferred mode of the lithium ion secondary battery negative electrode active material is the same as the first aspect.

下面分多个实施例对本发明实施例进行进一步的说明。本发明实施例不限定于以下的具体实施例。在不变主权利的范围内，可以适当的进行变更实施。 The embodiments of the present invention are further described below in various embodiments. The embodiments of the present invention are not limited to the specific embodiments below. Changes can be implemented as appropriate within the scope of the invariable principal rights.

实施例一 Embodiment 1

一种锂离子二次电池负极活性材料的制备方法，包括以下步骤： A method for preparing a negative active material for a lithium ion secondary battery, comprising the steps of:

( 1 )制备氮掺杂碳网 (1) Preparation of nitrogen-doped carbon network

将十六烷基三甲基溴化铵（ CTAB, (C₁₆H₃₃ )N(CH₃)₃Br, 7.3 g )溶解在冰水浴的 HC1 ( 120 mL, 1 mol/L )溶液中，超声分散均匀，然后将过硫酸铵 ( APS, 13.7 g )加入其中，立刻形成白色的悬浊液，搅拌 0.5小时后，再加入吡咯单体（Py, 8.3 mL ), 在 4 。C下保温反应 24 h后过滤，将得到的黑色沉淀物用 1 mol/L的 HC1溶液洗涤三次，再用纯净水洗涤至溶液呈无色中性，接着把沉淀物在 80。C 下干燥 24小时，最后将干燥后的沉淀物放置在管式炉中，通入 5 % H₂/Ar混合气，在 700 °C下烧结得 2小时即可得到氮掺杂碳网。 Dissolve cetyltrimethylammonium bromide (CTAB, (C ₁₆ H ₃₃ )N(CH ₃ ) ₃ Br, 7.3 g) in a solution of HC1 (120 mL, 1 mol/L) in an ice bath, sonicated The dispersion was uniform, then ammonium persulfate (APS, 13.7 g) was added thereto, and a white suspension was immediately formed. After stirring for 0.5 hour, a pyrrole monomer (Py, 8.3 mL) was further added at 4. After incubation for 24 hours, the mixture was filtered, and the obtained black precipitate was washed three times with a 1 mol/L HCl solution, and then washed with purified water until the solution was colorless neutral, and then the precipitate was at 80. The mixture was dried for 24 hours at C. Finally, the dried precipitate was placed in a tube furnace, and a nitrogen-doped carbon network was obtained by passing a 5% H ₂ /Ar mixture and sintering at 700 ° C for 2 hours.

( 2 ) 负载硅基活性物质 (2) Loaded silicon-based active substances

把氮掺杂碳网置于石英管中，将管式炉抽真空，按体积比为 1:1的比例通入硅源 SiH₄和 ¾, 控制气流量为 120 sccm, 以 10°C/min的升温速率将管式炉内升温至 600°C并保温 lOmin, 随后冷却至室温，制得锂离子二次电池负极活性材料。 The nitrogen-doped carbon mesh was placed in a quartz tube, and the tube furnace was evacuated, and the silicon source SiH ₄ and _{3⁄4 were introduced at a} volume ratio of 1:1 to control the gas flow rate to 120 sccm to 10 ° C/min. The heating rate was raised to 600 ° C in a tube furnace and kept for 10 minutes, and then cooled to room temperature to obtain a lithium ion secondary battery anode active material.

经 XRD分析，锂离子二次电池负极活性材料中硅基活性物质为单质硅，采用氯化铵重量法测得其质量比含量为 21.3%。氮掺杂的碳材料表面和内部的至少一处具有微孔，采用氮气吸附法，经 BET和 BJH计算，微孔孔径分布在 0.5~4 nm 之间。经 XPS分析，氮原子以吡啶型氮和吡咯型氮的形式存在。图 1为本发明实施例一制得的锂离子二次电池负极活性材料的 SEM电镜图。如图 1所示，所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，分支的直径约 50~80nm,硅基活性物质纳米颗粒的分布极为均匀且粒径在 10 nm左右。该结构充分利用了氮掺杂的碳材料的三维导电网络，硅基活性物质的低电导率对材料的整体导电特性几乎没有影响。同时，氮掺杂的碳材料的微孔可以有效降低硅基活性物质体积变化对材料整体寿命的影响。 According to XRD analysis, the silicon-based active material in the negative electrode active material of the lithium ion secondary battery is elemental silicon, and the mass ratio is 21.3% as measured by the ammonium chloride gravimetric method. At least one of the surface and inside of the nitrogen-doped carbon material has micropores, and the pore size distribution is 0.5 to 4 nm by nitrogen adsorption method, calculated by BET and BJH. between. By XPS analysis, the nitrogen atom is present in the form of a pyridine type nitrogen and a pyrrole type nitrogen. 1 is a SEM electron micrograph of a negative active material of a lithium ion secondary battery prepared in Example 1 of the present invention. As shown in FIG. 1, the lithium ion secondary battery anode active material includes a silicon-based active material and a nitrogen-doped carbon material, and the silicon-based active material is supported on the surface of the nitrogen-doped carbon material, and is doped with nitrogen. The carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the diameter of the branches is about 50-80 nm, and the distribution of the silicon-based active material nanoparticles is extremely uniform and the particle size is about 10 nm. The structure makes full use of the three-dimensional conductive network of the nitrogen-doped carbon material, and the low conductivity of the silicon-based active material has little effect on the overall conductive properties of the material. At the same time, the micropores of the nitrogen-doped carbon material can effectively reduce the influence of the volume change of the silicon-based active material on the overall life of the material.

实施例二 Embodiment 2

( 1 )制备氮掺杂碳网 (1) Preparation of nitrogen-doped carbon network

将管式炉抽真空，用 Ar负载气化的吡啶单体（pyridine )做反应气， Ar气流量控制为 50ml/min, 升降温速度 30°C/min, 700°C下保温 6小时，待管式炉冷却至室温，得到氮掺杂碳网。 The tube furnace was evacuated, and the pyridine monomer (pyridine) supported by Ar was used as the reaction gas. The Ar gas flow rate was controlled to 50 ml/min, the temperature rise and fall was 30 ° C/min, and the temperature was maintained at 700 ° C for 6 hours. The tube furnace was cooled to room temperature to obtain a nitrogen-doped carbon network.

( 2 ) 负载硅基活性物质 (2) Loaded silicon-based active substances

将氮掺杂碳网放入置于磁控溅射腔体，装上硅靶，抽真空至 10-³Pa, 通入气流量为 30sccm的保护性气体至磁控溅射腔体内压强为 3.0Pa,控制功率为 80W, 在 200°C溅射 2min, 随后冷却至室温，制得锂离子二次电池负极活性材料。 The nitrogen-doped carbon mesh is placed in a magnetron sputtering chamber, a silicon target is mounted, and a vacuum is applied to 10 - ³ Pa, and a protective gas having a gas flow rate of 30 sccm is introduced to a magnetron sputtering chamber with a pressure of 3.0. Pa, a control power of 80 W, sputtering at 200 ° C for 2 min, followed by cooling to room temperature, to obtain a lithium ion secondary battery negative active material.

所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面。经 XRD分析，锂离子二次电池负极活性材料中硅基活性物质为单质硅，采用氯化铵重量法测得其质量比含量为 23.6%。从 SEM来看，氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，分支的直径约 300~500nm, 硅纳米颗粒的直径在 100~200 nm之间。氮掺杂的碳材料表面和内部的至少一处具有微孔，采用氮气吸附法，经 BET和 BJH计算，微孔孔径分布在 50~150 nm之间。经 XPS分析，氮原子以吡啶型氮、吡咯型氮和石墨氮三种形式存在。图 2为本发明实施例制得的锂离子二次电池负极活性材料中氮掺杂碳网的结构示意图。如图 2所示，氮掺杂碳网中氮原子与碳原子通常以吡啶型氮、石墨型氮和吡咯型氮中的多种形式结合。 The lithium ion secondary battery anode active material includes a silicon-based active material and a nitrogen-doped carbon material, and the silicon-based active material is supported on a surface of the nitrogen-doped carbon material. According to XRD analysis, the silicon-based active material in the negative electrode active material of the lithium ion secondary battery is elemental silicon, and the mass ratio content thereof is 23.6% as measured by the ammonium chloride gravimetric method. From the SEM point of view, the nitrogen-doped carbon material is a three-dimensional network, and the nitrogen-doped carbon material includes A plurality of cross-linked branches having a diameter of about 300 to 500 nm and a diameter of silicon nanoparticles of 100 to 200 nm. At least one of the surface and the interior of the nitrogen-doped carbon material has micropores, and the pore size distribution is between 50 and 150 nm by nitrogen adsorption method, calculated by BET and BJH. According to XPS analysis, the nitrogen atom exists in the form of pyridine type nitrogen, pyrrole type nitrogen and graphite nitrogen. 2 is a schematic view showing the structure of a nitrogen-doped carbon mesh in a negative active material of a lithium ion secondary battery produced in an embodiment of the present invention. As shown in FIG. 2, the nitrogen atom and the carbon atom in the nitrogen-doped carbon network are usually combined in various forms of a pyridine type nitrogen, a graphite type nitrogen, and a pyrrole type nitrogen.

实施例三 Embodiment 3

取离子液体 3-甲基 -丁基吡啶二氰胺盐置于氧化铝坩埚中，转入管式炉内，通入保护性气体，以 2°C/min的升温速率将管式炉内升温至 600°C并保温 2h, 随后冷却至室温，制得离子液体裂解产物；随后将所述离子液体裂解产物加入 Y - 氨丙基三乙氧硅烷的水溶液中制得混合溶液，所述离子液体裂解产物与所述 γ - 氨丙基三乙氧硅烷的质量比为 8:5, 将所述混合溶液超声分散 30min随后置于容器中水浴加热至 85 °C ,向所述容器中滴入柠檬酸水溶液并恒温 85 °C搅拌反应 2h, 将反应后的溶液过滤，将滤渣于 80°C真空下烘烤 12h, 转入气氛烧结炉中，通入还原气氛，将烘烤后的产物在 500°C温度下烧结 4h, 随后冷却至室温，制得锂离子二次电池负极活性材料。 The ionic liquid 3-methyl-butylpyridine dicyanamide salt was placed in an alumina crucible, transferred into a tube furnace, and a protective gas was introduced to raise the temperature in the tube furnace at a heating rate of 2 ° C/min. The mixture is incubated at 600 ° C for 2 h, and then cooled to room temperature to prepare an ionic liquid cleavage product; then the ionic liquid cleavage product is added to an aqueous solution of Y-aminopropyltriethoxysilane to prepare a mixed solution, the ionic liquid The mass ratio of the cleavage product to the γ-aminopropyltriethoxysilane was 8:5, and the mixed solution was ultrasonically dispersed for 30 minutes, then placed in a water bath of a container and heated to 85 ° C, and the lemon was dropped into the container. The aqueous acid solution was stirred at a constant temperature of 85 ° C for 2 h, and the solution after the reaction was filtered. The filter residue was baked under vacuum at 80 ° C for 12 h, transferred to an atmosphere sintering furnace, and introduced into a reducing atmosphere, and the baked product was 500. After sintering at a temperature of ° C for 4 h, and then cooling to room temperature, a lithium ion secondary battery negative active material was obtained.

所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面。经 XRD分析，锂离子二次电池负极活性材料中硅基活性物质为硅和 SiOx的混合物，采用氯化铵重量法测得其质量比含量为 19.9%。从 SEM来看，氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，分支的直径约 50~100nm, 硅纳米颗粒的直径在 5~10 nm之间。氮掺杂的碳材料表面和内部的至少一处具有微孔，采用氮气吸附法，经 BET和 BJH计算，微孔孔径分布在 10~50 nm之间。经 XPS分析，氮原子以吡啶型氮、吡咯型氮和石墨氮三种形式存在。 The lithium ion secondary battery anode active material includes a silicon-based active material and a nitrogen-doped carbon material, and the silicon-based active material is supported on a surface of the nitrogen-doped carbon material. XRD analysis showed that the silicon-based active material in the negative electrode active material of the lithium ion secondary battery was a mixture of silicon and SiOx, and the mass ratio was 19.9% as measured by the ammonium chloride gravimetric method. From the SEM point of view, the nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the diameter of the branches is about 50-100 nm, and the diameter of the silicon nanoparticles is 5-10 nm. between. At least one of the surface and the interior of the nitrogen-doped carbon material has micropores, using nitrogen The adsorption method, calculated by BET and BJH, has a pore size distribution between 10 and 50 nm. According to XPS analysis, the nitrogen atom exists in the form of pyridine type nitrogen, pyrrole type nitrogen and graphite nitrogen.

对比例一 Comparative example one

将沥青置于石英管中，通入 5 % H₂/Ar混合气，在 700° C下烧结得 2小时碳化，再将管式炉抽真空，按体积比为 1： 1的比例通入硅源 SiH₄和 ¾, 控制气流量为 120 sccm, 以 10°C/min的升温速率将管式炉内升温至 600°C并保温 lOmin, 随后冷却至室温，制得碳 /硅复合锂离子二次电池负极活性材料。 The asphalt was placed in a quartz tube, passed through a 5% H ₂ /Ar mixture, sintered at 700 ° C for 2 hours to carbonize, and then the tube furnace was evacuated, and the silicon was introduced into the silicon at a volume ratio of 1:1. The source SiH ₄ and _3⁄4 , the control gas flow rate is 120 sccm, the temperature in the tube furnace is raised to 600 ° C at a heating rate of 10 ° C / min and kept for 10 min, and then cooled to room temperature to obtain a carbon/silicon composite lithium ion II. Secondary battery negative active material.

对比例二 Comparative example two

( 1 )制备氮掺杂碳网 (1) Preparation of nitrogen-doped carbon network

将十六烷基三甲基溴化铵（ CTAB, (C₁₆H₃₃ )N(CH₃)₃Br, 7.3 g )溶解在冰水浴的 HC1 ( 120 mL, 1 mol/L )溶液中，超声分散均匀，然后将过硫酸铵 ( APS, 13.7 g )加入其中，立刻形成白色的悬浊液，搅拌 0.5小时后，再加入吡咯单体（Py, 8.3 mL ), 在 4。C下保温反应 24 h后过滤，将得到的黑色沉淀物用 1 mol/L的 HC1溶液洗涤三次，再用纯净水洗涤至溶液呈无色中性，接着把沉淀物在 80。C 下干燥 24小时，最后将干燥后的沉淀物放置在管式炉中，通入 5 % H₂/Ar混合气，在 700 °C下烧结得 2小时即可得到氮掺杂碳网。 Dissolve cetyltrimethylammonium bromide (CTAB, (C ₁₆ H ₃₃ )N(CH ₃ ) ₃ Br, 7.3 g) in a solution of HC1 (120 mL, 1 mol/L) in an ice bath, sonicated The dispersion was uniform, and then ammonium persulfate (APS, 13.7 g) was added thereto, and a white suspension was immediately formed. After stirring for 0.5 hour, a pyrrole monomer (Py, 8.3 mL) was further added at 4. After incubation for 24 hours, the mixture was filtered, and the obtained black precipitate was washed three times with a 1 mol/L HCl solution, and then washed with purified water until the solution was colorless neutral, and then the precipitate was at 80. The mixture was dried for 24 hours at C. Finally, the dried precipitate was placed in a tube furnace, and a nitrogen-doped carbon network was obtained by passing a 5% H ₂ /Ar mixture and sintering at 700 ° C for 2 hours.

( 2 ) 负载硅基活性物质 (2) Loaded silicon-based active substances

把氮掺杂碳网置于石英管中，将管式炉抽真空，按体积比为 1: 1的比例通入硅源 SiH₄和 ¾, 控制气流量为 80 sccm, 以 10°C/min的升温速率将管式炉内升温至 1000°C并保温 20min, 随后冷却至室温，制得锂离子二次电池负极活性材料。 The nitrogen-doped carbon mesh was placed in a quartz tube, and the tube furnace was evacuated, and the silicon source SiH ₄ and _{3⁄4 were introduced at a} volume ratio of 1:1, and the control gas flow rate was 80 sccm to 10 ° C/min. The heating rate was raised to 1000 ° C in a tube furnace and kept for 20 minutes, and then cooled to room temperature to obtain a lithium ion secondary battery anode active material.

经 XRD分析，锂离子二次电池负极活性材料中硅基活性物质为单质硅，采用氯化铵重量法测得其质量比含量为 22.1%。从 SEM来看，氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，分支的直径约 50~80nm, 硅纳米颗粒的粒径分布在 1~3 μ m之间。采用氮气吸附法，经 BET和 BJH计算，微孔孔径分布在 0.5~4 nm之间。经 XPS分析，氮原子以吡啶型氮和吡咯型氮的形式存在。 XRD analysis, the silicon-based active material in the negative active material of lithium ion secondary battery is elemental silicon, The mass ratio was determined to be 22.1% by ammonium chloride gravimetric method. From the SEM point of view, the nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the diameter of the branches is about 50-80 nm, and the particle size distribution of the silicon nanoparticles is 1-3. Between μ m. The pore size distribution of the pores was between 0.5 and 4 nm by the nitrogen adsorption method and calculated by BET and BJH. By XPS analysis, the nitrogen atom is present in the form of a pyridine type nitrogen and a pyrrole type nitrogen.

对比例三 Comparative example three

( 1 )制备氮掺杂碳网 (1) Preparation of nitrogen-doped carbon network

将管式炉抽真空，用 Ar负载气化的吡啶单体（pyridine )做反应气， Ar气流量控制为 100ml/min, 升降温速度 50°C/min, 1000°C下保温 4小时，待管式炉冷却至室温，得到氮掺杂碳网。 The tube furnace was evacuated, and the pyridine monomer (pyridine) supported by Ar was used as the reaction gas. The Ar gas flow rate was controlled to 100 ml/min, the temperature rise and fall was 50 ° C/min, and the temperature was kept at 1000 ° C for 4 hours. The tube furnace was cooled to room temperature to obtain a nitrogen-doped carbon network.

( 2 ) 负载硅基活性物质 (2) Loaded silicon-based active substances

经 XRD分析，锂离子二次电池负极活性材料中硅基活性物质为单质硅，采用氯化铵重量法测得其质量比含量为 22.1%。从 SEM来看，氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，分支的直径约 15~30 μ ιη, 硅纳米颗粒的直径在 300~500 nm之间。采用氮气吸附法，经 BET和 BJH计算，孔孔径分布在 1~5 μ ιη之间。经 XPS分析，氮原子以吡啶型氮、吡咯型氮和石墨氮三种形式存在。 According to XRD analysis, the silicon-based active material in the negative electrode active material of the lithium ion secondary battery is elemental silicon, and the mass ratio content is 22.1% as measured by the ammonium chloride gravimetric method. From the SEM point of view, the nitrogen-doped carbon material has a three-dimensional network, and the nitrogen-doped carbon material includes a plurality of cross-linked branches, the diameter of the branches is about 15~30 μm, and the diameter of the silicon nanoparticles is 300-500. Between nm. Using a nitrogen adsorption method, the pore size distribution is between 1 and 5 μ ηη, calculated by BET and BJH. According to XPS analysis, nitrogen atoms exist in the form of pyridine nitrogen, pyrrole nitrogen and graphite nitrogen.

锂离子二次电池负极极片的制备 Preparation of negative electrode sheets for lithium ion secondary batteries

将上述实施例一中制得的锂离子二次电池负极活性材料与导电剂（ Timcal , Super-p 和 SFG-6 ) 混合均匀，然后加入 8%的聚偏氟乙烯 PVDF ( Arkmer, HSV900 )、 N-甲基吡咯烷酮溶液 NMP, 搅拌均勾，将上述混合浆料均勾涂布在 ΙΟμιη的铜箔集流体上，在 110°C和真空条件下烘烤 12h, 即得到锂离子二次电池负极极片。其中，锂离子二次电池负极混合浆料的配方为（质量比）：锂离子二次电池负极活性材料： super-p: SFG-6: PVDF= 92: 3:1:4。 The lithium ion secondary battery anode active material prepared in the above first embodiment and the conductive agent ( Timcal , Super-p and SFG-6) were mixed evenly, then 8% polyvinylidene fluoride PVDF (Arkmer, HSV900) and N-methylpyrrolidone solution NMP were added, and the mixture was stirred and hooked. The above mixed slurry was coated on ΙΟμιη. The copper foil current collector was baked at 110 ° C under vacuum for 12 h to obtain a negative electrode tab for a lithium ion secondary battery. Among them, the formulation of the lithium ion secondary battery negative electrode mixture slurry is (mass ratio): lithium ion secondary battery anode active material: super-p: SFG-6: PVDF = 92: 3:1:4.

锂离子二次电池的制备 Preparation of lithium ion secondary battery

将上述锂离子二次电池负极极片做成 2016型扣式电池，其中，对电极采用锂金属，隔膜为 celgard C2400, 电解液为 1.3M LiPF₆的 EC和 DEC (体积比为 3:7 )溶液。 The lithium ion secondary battery negative electrode piece is made into a 2016 type button battery, wherein the counter electrode is made of lithium metal, the diaphragm is celgard C2400, and the electrolyte is 1.3M LiPF ₆ of EC and DEC (volume ratio of 3:7) Solution.

实施例二、实施例三、以及对比例一 ~对比例三中制得的锂离子二次电池负极活性材料均同此处理。 The lithium ion secondary battery negative active material prepared in Example 2, Example 3, and Comparative Example 1 to Comparative Example 3 were treated in the same manner.

效果实施例为有力支持本发明实施例的有益效果，提供效果实施例如下，用以评测本发明实施例提供的产品的性能。 Effect Embodiments In order to strongly support the advantageous effects of the embodiments of the present invention, an effect is provided, for example, to evaluate the performance of the products provided by the embodiments of the present invention.

将实施例一~实施例三以及对比例一~对比例三中制得的扣式锂离子二次电池以 100mA/lg活性物质的电流充电至电压为 0.001V, 接着恒压直至电流小于 10mA/lg活性物质；搁置 lOmin; 在将上述扣式电池以 100mA/lg活性物质的电流放电至 2.5V。完成上述充、电放电过程记为 1个充 /电放电循环。扣式锂离子二次电池的首次库伦效率和容量保持率的公式分别如下，结果记录在表 1中：首次库伦效率（％) = 首次充电容量 /首次放电容量 χ100%; The button-type lithium ion secondary battery prepared in Example 1 to Example 3 and Comparative Example 1 to Comparative Example 3 was charged with a current of 100 mA/lg of active material to a voltage of 0.001 V, followed by a constant voltage until the current was less than 10 mA/ Lg active substance; shelved for 10 minutes; the above button cell was discharged to a current of 2.5 mA/lg of active material to 2.5V. The above charging and discharging process is completed as one charging/electric discharging cycle. The formulas for the first coulombic efficiency and capacity retention of the button lithium ion secondary battery are as follows, and the results are recorded in Table 1: First Coulomb efficiency (%) = First charge capacity / First discharge capacity χ 100%;

第 n次循环的容量保持率（％ ) = 第 n次循环的放电容量 /第 1次循环的放电容量 χ100%。表 1.扣式锂离子二次电池测试结果 The capacity retention ratio (%) of the nth cycle = the discharge capacity of the nth cycle / the discharge capacity of the first cycle χ 100%. Table 1. Test results of button lithium ion secondary battery

从表 1中可以看出，本发明实施例一~实施例三制得的锂离子二次电池负极活性材料与同等温度下的对比例一制得的锂离子二次电池负极活性材料硅 /碳复合材料比较具有长的循环寿命、高的容量和首次效率，这是因为氮掺杂碳网本身具有比碳更高的容量和电导率，同时氮掺杂的碳材料的微孔可以有效降低硅基活性物质体积变化对材料整体寿命的影响。本发明实施例一~实施例三制得的锂离子二次电池负极活性材料与同等温度下的对比例二和三制得的锂离子二次电池负极活性材料比较，其硅基活性物质纳米颗粒大小与氮掺杂的碳材料分支直径及氮掺杂的碳材料微孔孔径分布的搭配更合理，电导率高，具有更高的容量、首次效率和循环寿命。

As can be seen from Table 1, the negative active material of the lithium ion secondary battery prepared in the first to third embodiments of the present invention and the comparative example at the same temperature, the lithium ion secondary battery anode active material silicon/carbon Composite materials have long cycle life, high capacity, and first efficiency because nitrogen-doped carbon networks have higher capacity and conductivity than carbon, while micropores of nitrogen-doped carbon materials can effectively reduce silicon. The effect of volume change of the base active material on the overall life of the material. The negative electrode active material of the lithium ion secondary battery prepared in the first embodiment to the third embodiment of the present invention is compared with the negative electrode active material of the lithium ion secondary battery prepared by the comparative examples 2 and 3 at the same temperature, and the silicon-based active material nanoparticle is compared. The combination of size and nitrogen-doped carbon material branch diameter and nitrogen-doped carbon material pore size distribution is more reasonable, high conductivity, higher capacity, first efficiency and cycle life.

Claims

权利要求 Rights request

1、一种锂离子二次电池负极活性材料，其特征在于，包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 1. A lithium ion secondary battery negative active material, characterized in that it includes a silicon-based active material and a nitrogen-doped carbon material, and the silicon-based active material is loaded on the surface of the nitrogen-doped carbon material, The silicon-based active material is one or more of nanoparticles and nanowires. The particle size of the silicon-based active material nanoparticles is 1 to 1 μm, and the diameter of the nanowire is 1 to 200 nm and the length is 1 ~10 μm, the nitrogen-doped carbon material is in a three-dimensional network shape, the nitrogen-doped carbon material includes a plurality of mutually cross-linked branches, the diameter of the branches is 1nm~10 μm, the nitrogen-doped carbon material At least one of the surface and interior of the carbon material has micropores. The nitrogen-doped carbon material is made of a nitrogen-doped carbon network. The nitrogen atoms and carbon atoms in the nitrogen-doped carbon network are composed of pyridinic nitrogen and graphite. At least one form of nitrogen and pyrrole nitrogen is combined.

2、如权利要求 1所述的一种锂离子二次电池负极活性材料，其特征在于，所述锂离子二次电池负极活性材料中所述硅基活性物质的质量比含量为 0.1%~80%。 2. A lithium-ion secondary battery negative active material as claimed in claim 1, characterized in that the mass ratio content of the silicon-based active material in the lithium-ion secondary battery negative active material is 0.1% to 80 %.

3、如权利要求 1所述的一种锂离子二次电池负极活性材料，其特征在于，所述氮掺杂的碳材料分支的直径与所述硅基活性物质纳米颗粒的粒径的比例为 1~10:1。 3. A lithium ion secondary battery negative active material according to claim 1, characterized in that the ratio of the diameter of the nitrogen-doped carbon material branch to the particle size of the silicon-based active material nanoparticles is 1~10:1.

4、如权利要求 1所述的一种锂离子二次电池负极活性材料，其特征在于，所述微孔的孔径分布在 0.5~500nm。 4. A lithium ion secondary battery negative active material as claimed in claim 1, characterized in that the pore size of the micropores is distributed between 0.5 and 500 nm.

5、如权利要求 1所述的一种锂离子二次电池负极活性材料，其特征在于，所述氮掺杂碳网中含有吡咯型氮。 5. A lithium ion secondary battery negative active material as claimed in claim 1, characterized in that, The nitrogen-doped carbon network contains pyrrole nitrogen.

6、如权利要求 1所述的一种锂离子二次电池负极活性材料，其特征在于，所述硅基活性物质的材质选自单质硅、硅氧化物和硅合金中的一种或几种。 6. A lithium ion secondary battery negative active material according to claim 1, characterized in that the material of the silicon-based active material is selected from one or more of elemental silicon, silicon oxide and silicon alloy. .

7、一种锂离子二次电池负极活性材料的制备方法，其特征在于，按以下方法中的一种进行制备： 7. A method for preparing a negative active material for a lithium ion secondary battery, which is characterized in that it is prepared according to one of the following methods:

方法一：通过化学气相沉积法在氮掺杂碳网表面负载硅基活性物质，制得锂离子二次电池负极活性材料； Method 1: Load silicon-based active materials on the surface of nitrogen-doped carbon mesh through chemical vapor deposition to prepare negative active materials for lithium-ion secondary batteries;

方法二：通过磁控溅射法在氮掺杂碳网表面负载硅基活性物质，制得锂离子二次电池负极活性材料； Method 2: Load silicon-based active materials on the surface of nitrogen-doped carbon mesh through magnetron sputtering to prepare negative active materials for lithium-ion secondary batteries;

方法三：将离子液体 3-甲基-丁基吡啶二氰胺盐或 1-乙基 -3-甲基咪唑二氰胺的裂解产物与硅前躯体溶液共混制得混合溶液，所述硅前躯体为 γ -氨丙基三乙氧硅烷、 Υ - ( 2,3-环氧丙氧）丙基三甲氧基硅烷和 γ -甲基丙烯酰氧基丙基三甲氧基硅烷中的一种或几种，将所述混合溶液超声分散后水浴加热，向所述水浴体系中滴入络合剂，随后将含有络合剂的混合溶液搅拌反应，将反应后的产物烘烤后烧结，制得锂离子二次电池负极活性材料； Method 3: Blend the ionic liquid 3-methyl-butylpyridinedicyanamide salt or the cracked product of 1-ethyl-3-methylimidazoledicyanamide with the silicon precursor solution to prepare a mixed solution. The silicon The precursor is one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane or several, the mixed solution is ultrasonically dispersed and heated in a water bath, a complexing agent is dripped into the water bath system, and then the mixed solution containing the complexing agent is stirred and reacted, and the reacted product is baked and sintered to prepare Obtain negative active materials for lithium-ion secondary batteries;

所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ m, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 The negative active material of the lithium ion secondary battery includes a silicon-based active material and a nitrogen-doped carbon material. The silicon-based active material is loaded on the surface of the nitrogen-doped carbon material. The silicon-based active material is a nanoparticle. and one or more types of nanowires, the silicon-based active material nanoparticles have a particle size of 1 to 1 μm, the nanowires have a diameter of 1 to 200 nm and a length of 1 to 10 μm, The nitrogen-doped carbon material is in the form of a three-dimensional network. The nitrogen-doped carbon material includes a plurality of cross-linked branches. The diameter of the branches is 1nm~10 μm. The surface and interior of the nitrogen-doped carbon material are At least one place has micropores, and the nitrogen-doped carbon material The material of is a nitrogen-doped carbon network, and the nitrogen atoms and carbon atoms in the nitrogen-doped carbon network are combined in at least one form of pyridine nitrogen, graphitic nitrogen, and pyrrole nitrogen.

8、如权利要求 7所述的一种锂离子二次电池负极活性材料的制备方法，其特征在于， 8. The method for preparing anode active material of lithium ion secondary battery according to claim 7, characterized in that,

方法一中所述通过化学气相沉积法在氮掺杂碳网表面负载硅基活性物质为：取氮掺杂碳网置于管式炉内，将管式炉抽真空，按体积比为 1:0.1~10的比例通入硅源 SiH₄和保护性气体，控制气流量为 30~300 sccm, 以 l~50°C/min的升温速率将管式炉内升温至 500~1300°C并保温 3~60min, 随后冷却至室温，制得锂离子二次电池负极活性材料； The silicon-based active material loaded on the surface of the nitrogen-doped carbon mesh through chemical vapor deposition as described in Method 1 is: Place the nitrogen-doped carbon mesh in a tubular furnace, evacuate the tubular furnace, and the volume ratio is 1: Pour in the silicon source SiH ₄ and protective gas at a ratio of 0.1 to 10, control the gas flow to 30 to 300 sccm, and heat the tube furnace to 500 to 1300°C at a heating rate of 1 to 50°C/min and keep it warm. 3~60min, and then cooled to room temperature to prepare the negative active material of lithium ion secondary battery;

方法二中所述通过磁控溅射法在氮掺杂碳网表面负载硅基活性物质为：取氮掺杂碳网置于磁控溅射腔体，装上硅靶，抽真空至 0~10-²Pa, 通入气流量为 10~300sccm 的保护性气体至磁控溅射腔体内压强为 l~10Pa , 控制功率为 10-200W, 在 100~400°C溅射 l~10min, 随后冷却至室温，制得锂离子二次电池负极活性材料； As described in Method 2, loading silicon-based active material on the surface of nitrogen-doped carbon mesh through magnetron sputtering is as follows: place the nitrogen-doped carbon mesh in the magnetron sputtering cavity, install the silicon target, and evacuate to 0~ ^10-2 Pa, introduce protective gas with a gas flow rate of 10~300 sccm to the pressure in the magnetron sputtering chamber of 1~10 Pa, control power 10-200W, sputter at 100~400°C for 1~10 min, and then Cool to room temperature to prepare the negative active material of lithium ion secondary battery;

方法三中所述离子液体裂解产物与所述硅前 ^区体的质量比为 1:0.1~5 , 所述络合剂为柠檬酸、酒石酸、 EDTA和丁二酸钠的一种或几种，将含有络合剂的混合溶液恒温 50~100°C搅拌下反应 0.5~5h,将反应后的产物于 50~100°C真空下烘烤 l~24h, 再转入气氛烧结炉中，在保护性气体氛围下 500~1300°C烧结 l~10h, 随后冷却至室温。 The mass ratio of the ionic liquid cracked product and the silicon precursor in method three is 1:0.1~5, and the complexing agent is one or more of citric acid, tartaric acid, EDTA and sodium succinate. , react the mixed solution containing the complexing agent at a constant temperature of 50~100°C with stirring for 0.5~5h, bake the reacted product under vacuum at 50~100°C for 1~24h, and then transfer it to an atmosphere sintering furnace. Sintering at 500~1300°C for 1~10h under protective gas atmosphere, then cooled to room temperature.

9、一种锂离子二次电池负极极片，其特征在于，所述锂离子二次电池负极极片包括集流体和涂覆在所述集流体上的锂离子二次电池负极活性材料，所述锂离子二次电池负极活性材料包括硅基活性物质和氮掺杂的碳材料 , 所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη,所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 9. A lithium ion secondary battery negative electrode sheet, characterized in that, the lithium ion secondary battery negative electrode sheet includes a current collector and a lithium ion secondary battery negative electrode active material coated on the current collector, so describe The negative active material of the lithium ion secondary battery includes a silicon-based active material and a nitrogen-doped carbon material. The silicon-based active material is loaded on the surface of the nitrogen-doped carbon material. The silicon-based active material is nanoparticles and nanometers. One or more of the wires, the particle size of the silicon-based active material nanoparticles is 1~1 μm, the diameter of the nanowire is 1~200nm and the length is 1~10 μm, the nitrogen-doped The hybrid carbon material is in the form of a three-dimensional network. The nitrogen-doped carbon material includes a plurality of cross-linked branches. The diameter of the branch is 1 to 10 μm. At least one of the surfaces and interior of the nitrogen-doped carbon material has has micropores, and the nitrogen-doped carbon material is made of a nitrogen-doped carbon network. The nitrogen atoms and carbon atoms in the nitrogen-doped carbon network are composed of at least one of pyridinic nitrogen, graphitic nitrogen, and pyrrole nitrogen. A form of union.

10、一种锂离子二次电池，其特征在于，所述锂离子二次电池由锂离子二次电池负极极片、正极极片、隔膜、非水电解液和外壳组成，所述锂离子二次电池负极极片包括硅基活性物质和氮掺杂的碳材料，所述硅基活性物质负载在所述氮掺杂的碳材料表面，所述硅基活性物质为纳米颗粒和纳米线中的一种或几种，所述硅基活性物质纳米颗粒的粒径为 1ηιη~1 μ ιη, 所述纳米线的直径为 l~200nm且长度为 1~10 μ ιη, 所述氮掺杂的碳材料呈三维网状，氮掺杂的碳材料包括多根相互交联的分支，所述分支的直径为 1ηιη~10 μ ιη, 所述氮掺杂的碳材料表面和内部的至少一处具有微孔，所述氮掺杂的碳材料的材质为氮掺杂碳网，所述氮掺杂碳网中氮原子与碳原子以吡啶型氮、石墨型氮和吡咯型氮中的至少一种形式结合。 10. A lithium ion secondary battery, characterized in that the lithium ion secondary battery is composed of a lithium ion secondary battery negative electrode plate, a positive electrode plate, a separator, a non-aqueous electrolyte and a casing, and the lithium ion secondary battery is The negative electrode plate of the secondary battery includes a silicon-based active material and a nitrogen-doped carbon material. The silicon-based active material is loaded on the surface of the nitrogen-doped carbon material. The silicon-based active material is nanoparticles and nanowires. One or more, the particle size of the silicon-based active material nanoparticles is 1~1 μm, the diameter of the nanowire is 1~200nm and the length is 1~10 μm, the nitrogen-doped carbon The material is in the form of a three-dimensional network. The nitrogen-doped carbon material includes a plurality of interconnected branches. The diameter of the branches is 1 to 10 μm. At least one of the surface and the interior of the nitrogen-doped carbon material has microstructure. hole, the nitrogen-doped carbon material is made of a nitrogen-doped carbon network, and the nitrogen atoms and carbon atoms in the nitrogen-doped carbon network are in the form of at least one of pyridine nitrogen, graphitic nitrogen, and pyrrole nitrogen. combine.