阅读说明：本技术 一种高电位锂离子电池ncm三元正极材料及其制备方法 (A kind of high potential lithium ion battery NCM tertiary cathode material and preparation method thereof ) 是由 刘兴泉 冉淇文 李蕾 刘金涛 郝帅 何泽珍 胡友作 李�浩 肖雨 于 2019-08-28 设计创作，主要内容包括：本发明属于锂离子电池领域,涉及锂离子电池正极材料及其制备方法,具体为一种高电位锂离子电池NCM三元正极材料及其制备方法；用以克服现有锂离子电池正极材料层状高镍镍钴锰酸锂NCM811及其衍生品电化学循环性能差的缺点。本发明正极材料的分子表达式为：Li(Ni<Sub>0.8</Sub>Co<Sub>0.1</Sub>Mn<Sub>0.1</Sub>)<Sub>1-x-y</Sub>Si<Sub>x</Sub>O<Sub>2</Sub>@(Li<Sub>2</Sub>SiO<Sub>3</Sub>)<Sub>y</Sub>、0<x+y≤0.2、且y＜＜x；本发明采用循环过程中抑制微裂纹产生的高价态Si<Sup>4+</Sup>梯度掺杂结合表面形成的Li<Sub>2</Sub>SiO<Sub>3</Sub>包覆改性,该锂离子电池正极材料具有较高的放电比容量和优异的循环稳定性能,能够满足较大倍率充放电循环需求,其制备方法采用传统的固相法进行体相掺杂,操作简单,易于工业化生产,制备的产品纯度高、化学均匀高、结晶品质高、产物颗粒细小且分布均匀、电化学性能优良且制造成本较低。(The invention belongs to field of lithium ion battery, are related to anode material for lithium-ion batteries and preparation method thereof, specially a kind of high potential lithium ion battery NCM tertiary cathode material and preparation method thereof；The shortcomings that overcome the nickelic nickle cobalt lithium manganate NCM811 of existing anode material for lithium-ion batteries stratiform and its spin-off electrochemistry poor circulation.The biomolecule expressions of positive electrode of the present invention are as follows: Li (Ni 0.8 Co 0.1 Mn 0.1 ) 1‑x‑y Si x O 2 @(Li 2 SiO 3 ) y , 0 < x+y≤0.2 and y < < x；The present invention is using the high-valence state Si for inhibiting micro-crack to generate in cyclic process 4+ The Li that grade doping mating surface is formed 2 SiO 3 Coating modification, anode material for lithium-ion batteries specific discharge capacity with higher and excellent stable circulation performance, it can satisfy and recycle demand compared with high rate charge-discharge, preparation method is carried out bulk phase-doped using traditional solid phase method, it is easy to operate, it is easy to industrialized production, the product purity of preparation is high, chemical homogeneous is high, crystalline quality is high, product grain is tiny and be evenly distributed, excellent electrochemical performance and manufacturing cost it is lower.)

1. a kind of high potential lithium ion battery NCM tertiary cathode material, which is characterized in that the biomolecule expressions of the positive electrode Are as follows: Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y, wherein 0 < x+y≤0.2 and y < < x.

2. by the preparation method of high potential lithium ion battery NCM tertiary cathode material described in claim 1, which is characterized in that packet Include following steps:

Step 1. is using alcohol or pure water as dispersing agent, with Ni_0.8Co_0.1Mn_0.1(OH)₂And its spin-off is presoma, by presoma In molar ratio with silicon source: (1-x-y): (x+y) carries out mixed grinding, and drying after grinding uniformly obtains mixture 1；

Step 2. is using alcohol or pure water as dispersing agent, in molar ratio by lithium source and step 1 gained mixture 1: (1~1.15): 1 into Row mixed grinding, drying after grinding uniformly, obtains mixture 2；

Mixture 2 is placed in tube furnace by step 3., under oxygen atmosphere, is first warming up to 480~580 DEG C of pre-burnings 6 with 3 DEG C/min ~12h, then 750~850 DEG C of roastings 15~for 24 hours are warming up to 2 DEG C/min, by the levigate sieving of product after Temperature fall, Li is made (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y, wherein 0 < x+y≤0.2 and y < < x.

3. by the preparation method of high potential lithium ion battery NCM tertiary cathode material described in claim 2, which is characterized in that In In step 2, the lithium source raw material is at least one in lithium carbonate, lithium nitrate, lithium acetate, lithium chloride, lithia and lithium hydroxide Kind.

4. by the preparation method of high potential lithium ion battery NCM tertiary cathode material described in claim 2, which is characterized in that In In step 1, the silicon source raw material is silica, nano silica, silicon tetrachloride, ethyl orthosilicate, metasilicic acid ethyl ester, just At least one of silicate, metasilicate.

Technical field

The invention belongs to field of lithium ion battery, are related to anode material for lithium-ion batteries and preparation method thereof, specially lithium Ion battery positive electrode Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yAnd preparation method thereof, wherein 0 < x+y≤ 0.2。

Background technique

Lithium ion battery is because it is high with energy density, self discharge is small, stable circulation performance is excellent and memory-less effect The features such as, become vital a part in power battery field in new-energy automobile industry instantly.Lithium-ion electric Pond is mainly made of positive electrode, negative electrode material, diaphragm and electrolyte；Wherein, anode material for lithium-ion batteries industrializes at present Mainly have: cobalt acid lithium, LiMn2O4, LiFePO4 and tertiary cathode material；Tertiary cathode material (NCM) mainly includes following several Kind material: LiNi_0.333Co_0.333Mn_0.333O₂(111)、LiNi_0.5Co_0.2Mn_0.3O₂(523)、LiNi_0.6Co_0.2Mn_0.2O₂(622)、 LiNi_0.8Co_0.1Mn_0.1O₂(811).In order to meet demand of the market to positive electrode energy density, tertiary cathode material is positive Nickelic (Ni >=0.6) direction is developed, and the specific capacity of material can be increased significantly, but lithium nickel cation mixing effect enhances, material Cyclical stability decline.Existing market is for LiNi_0.8Co_0.1Mn_0.1O₂Energy density more stringent requirements are proposed, improve just Pole material by voltage be a kind of feasible method；But with the raising by voltage, side reaction can aggravate therewith, material Stable circulation performance sharply decline；And a large number of studies show that: the main reason for material circulation performance is poor, after circulation, A large amount of micro-cracks that active material generates on anode pole piece, increase the polarization of material, and impedance increases, electrolyte permeability to fine fisssure Short circuit etc. is caused in line.

Summary of the invention

It is an object of the invention to be directed to the nickelic nickle cobalt lithium manganate NCM811 of anode material for lithium-ion batteries stratiform (LiNi_0.8Mn_0.1Co_0.1O₂) and its shortcomings that spin-off electrochemistry poor circulation, especially in high blanking voltage, The high-valence state Si for inhibiting micro-crack to generate in a kind of cyclic process is provided⁴⁺The Li that grade doping mating surface is formed₂SiO₃Cladding Modified anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yAnd preparation method thereof, wherein 0 < x+y≤0.2.Anode material for lithium-ion batteries specific discharge capacity with higher and excellent stable circulation performance, Neng Gouman Foot recycles demand compared with high rate charge-discharge, and preparation method is bulk phase-doped using traditional solid phase method progress, easy to operate, is easy to Industrialized production, the product purity of preparation is high, chemical homogeneous is high, crystalline quality is high, product grain is tiny and is evenly distributed, electrification It learns function admirable and manufacturing cost is lower.

To achieve the above object, the technical solution adopted by the present invention are as follows:

A kind of high potential anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y, feature It is, the biomolecule expressions of the anode material for lithium-ion batteries are as follows: Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y, Wherein, 0 < x+y≤0.2 and y " x ,@expression Li₂SiO₃It is coated on Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂Surface.

Above-mentioned anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yPreparation method, It is characterized in that, comprising the following steps:

Step 1. is using alcohol or pure water as dispersing agent, and in molar ratio with silicon source by presoma: (1-x-y): (x+y) is mixed Grinding is closed, drying after grinding uniformly obtains mixture 1；

Step 2. is using alcohol or pure water as dispersing agent, in molar ratio with step 1 gained mixture 1 by lithium source: (1~ 1.15): 1 carries out mixed grinding, and drying after grinding uniformly obtains mixture 2；

Mixture 2 is placed in tube furnace by step 3., under oxygen atmosphere, is first warming up to 480~580 DEG C with 3 DEG C/min 6~12h of pre-burning, then 750~850 DEG C of roastings 15~for 24 hours are warming up to 2 DEG C/min, by the levigate sieving of product after Temperature fall, system Obtain Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y, wherein 0 < x+y≤0.2 and y " x.

In step 1, the presoma is Ni_0.8Co_0.1Mn_0.1(OH)₂And its spin-off.

In step 2, the lithium source raw material is lithium carbonate, lithium nitrate, lithium acetate, lithium chloride, lithia and lithium hydroxide At least one of.

In step 1, the silicon source raw material be silica, nano silica, silicon tetrachloride, ethyl orthosilicate, partially At least one of silester, orthosilicate, metasilicate.

The present invention is by high-valence state Si⁴⁺Adulterate and be autonomously formed fast lithium ion conductor Li₂SiO₃Surrounding phase combines, to nickel cobalt manganese Sour lithium (LiNi_0.8Mn_0.1Co_0.1O₂) a small amount of Si of incorporation⁴⁺(0 < x+y≤0.2), Si⁴⁺The position of grade doping substitution transition metal It sets；Meanwhile Si⁴⁺Li is automatically generated with surface residual alkali₂SiO₃Surface cladding is carried out, to obtain anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y；On the one hand, a small amount of Si⁴⁺Bulk phase-doped, silicon oxygen bond forms hinge knot Structure improves the internal structure stability of material, it is suppressed that the generation of crizzle；On the other hand, due to silica with The effect of surface residual alkali consumes surface residual alkali, reduces surface alkalinty, improves material processing performance；Surface Creation Li₂SiO₃To Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂Surface cladding has been carried out, surface side reaction has effectively been inhibited, improves table The stability in face, while the lithium ion conductivity of material is improved, it obtains compared to nickle cobalt lithium manganate tertiary cathode material (LiNi_0.8Co_0.1Mn_0.1O₂) the more stable Li (Ni of structure_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y, and have higher Specific capacity and superior cyclical stability.In addition, Li₂SiO₃Surface cladding is given birth to automatically by silica and surface residual alkali At, therefore its covering amount is far smaller than Si⁴⁺Doping, i.e. y " x.

In conclusion the present invention has the advantage that

1, Li (Ni prepared by the present invention_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yLayered lithium ion battery anode material Material, passes through minimal amount of Si⁴⁺Grade doping replaces the position of transition metal, and the fast lithium ion conductor of stratiform automatically generated Li₂SiO₃Surface cladding, to stabilize the internal structure of material, it is suppressed that the generation of crizzle；Surface coats simultaneously The side reaction of surfacing and electrolyte is decreased, the transmission rate of lithium ion in positive electrode is enhanced.

2, present invention doping uses solid phase method, by grinding for a long time, can be realized more uniform doping dispersion；Gram The shortcomings that having taken Traditional liquid phase synthetic method, the clad chemical uniformity of preparation is good, the coating thickness of formation is very thin.

3, high potential positive electrode Li (Ni prepared by the present invention_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yWith compared with High specific discharge capacity and excellent cycle performance；Under room temperature environment, when voltage range is in 2.8~4.3V, constant current charge and discharge When electric multiplying power is 0.33C, the first discharge specific capacity of the anode material for lithium-ion batteries can reach 160.5mAh g^-1, circulation 100 It still can reach 153.9mAh g after secondary^-1, capacity retention ratio 95.8%；When voltage range is in 2.8~4.5V, constant current charge and discharge When electric multiplying power is 0.5C, the initial discharge specific capacity of the anode material for lithium-ion batteries can reach 180.0mAh g^-1, recycle 50 times It still can reach 162.6mAh g later^-1, capacity retention ratio is up to 90.3%.

4, it generates in preparation process of the invention without poisonous and harmful substance, is produced involved in environmentally friendly and technique Equipment is simple, is relatively easy to realize scale industrial production.

Detailed description of the invention

Fig. 1 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y's Process flow chart.

Fig. 2 is that the present invention prepares the bulk phase-doped persursor material (Ni of silicon_0.8Co_0.1Mn_0.1)_1-x-ySi_x+y(OH)₂Technique Flow chart.

Fig. 3 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_y's XRD diagram.

Fig. 4 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_ySEM figure.

Fig. 5 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yIn In 2.8~4.3V voltage range, with 0.33C rate charge-discharge, initial charge/discharge curve graph.

Fig. 6 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yIn In 2.8~4.3V voltage range, with 0.33C rate charge-discharge, cycle performance curve graph.

Fig. 7 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yIn In 2.8~4.5V voltage range, with 0.5C rate charge-discharge, initial charge/discharge curve graph.

Fig. 8 is that the present invention prepares anode material for lithium-ion batteries Li (Ni_0.8Co_0.1Mn_0.1)_1-x-ySi_xO₂@(Li₂SiO₃)_yIn In 2.8~4.5V voltage range, with 0.5C rate charge-discharge, cycle performance curve graph.

Specific embodiment

The present invention is described in further detail with attached drawing combined with specific embodiments below.