CN103078087A - Preparation method of lithium titanate/carbon nano tube composite cathode material - Google Patents

Abstract

Translated fromChinese

本发明公开了一种钛酸锂/碳纳米管复合负极材料的制备方法，属于电池材料技术领域。本发明采用化学气相沉积法在钛酸锂表面生长碳纳米管，其与直接在钛酸锂中掺杂碳纳米管相比具有分散均匀、结合力强等特性，同时生长的碳纳米管更易在钛酸锂表面形成网状结构，对提高电池在大倍率放电条件下材料的结构稳定起到重要作用。本发明中锂离子电池通过利用碳纳米管的高导电性及其形成的网络结构以提高与钛酸锂的接触机率，降低内阻、减小极化，同时碳纳米管较大的比表面积又可以提高负极材料的吸液保液能力，从而提高电池的大倍率放电能力和电池的循环能力。

The invention discloses a preparation method of a lithium titanate/carbon nanotube composite negative electrode material, belonging to the technical field of battery materials. The present invention adopts the chemical vapor deposition method to grow carbon nanotubes on the surface of lithium titanate. Compared with directly doping carbon nanotubes in lithium titanate, it has the characteristics of uniform dispersion and strong binding force. The network structure formed on the surface of lithium titanate plays an important role in improving the structural stability of the battery under high-rate discharge conditions. In the present invention, the lithium-ion battery utilizes the high conductivity of carbon nanotubes and the network structure formed to increase the contact probability with lithium titanate, reduce internal resistance, and reduce polarization. At the same time, the larger specific surface area of carbon nanotubes is also It can improve the liquid absorption and liquid retention capacity of the negative electrode material, thereby improving the high rate discharge capacity of the battery and the cycle capacity of the battery.

Description

A kind of preparation method of lithium titanate/carbon/carbon nano tube composite negative pole material

Technical field

The present invention relates to a kind of preparation method of lithium ion battery negative material, relate to specifically a kind of preparation method of lithium titanate/carbon/carbon nano tube composite negative pole material, belong to the battery material technical field.

Background technology

Lithium ion battery is a kind of novel energy storage cell that grew up in recent years, concern so that it has extended cycle life, working voltage platform is steady, the advantage such as cheap and pollution-free is subject to people now has been widely used in the fields such as electric automobile, wind energy energy storage, mobile power station.

At present, lithium ion battery negative adopts graphite type material more, but the graphite negative electrodes material since cycle life is poor, fail safe is low etc. drawbacks limit its extensive use in field of batteries.Spinel type lithium titanate is a kind of zero strain material, have good cycle, with electrolyte reaction, the charging/discharging voltage platform is steady, safe, price is low and the advantage such as easy preparation, is the desirable negative material of preparation long-life, high security battery.Yet, point product stone type lithium titanate material self electronic conductance and ionic conductance are lower, and capacity attenuation is fast when high current charge-discharge, and high rate performance is relatively poor, affect its application under the high current charge-discharge condition, therefore improve the key that high rate performance becomes the lithium titanate practicalization.

At present, improve Li₄Ti₅0₁₂High rate performance is mainly by two approach: the one, lithium titanate is prepared into the nano barium titanate lithium material; The 2nd, doped conducting metal and material with carbon element.Chinese patent (publication number: CN101630732A) disclose the employing sol-gel process a certain proportion of carbon nano tube dispersion liquid and titanium, lithium compound and doped chemical solution mixed after, heat drying makes the gel precursor, and sintering obtains a kind of carbon nano-tube to coat particle diameter be the preparation method of nano level lithium titanate compound under the inert atmosphere.Same Chinese patent (application number: 201110000627.3) also disclose a kind of in lithium titanate directly doped carbon nanometer pipe prepare anode material, thereby improve the method for battery high rate performance.Yet, the composite negative pole material that said method makes, carbon nano-tube and lithium titanate just simply mix, and wherein carbon nano-tube is all relatively poor in lithium titanate surface distributed uniformity and adhesion, and is very limited to the increase rate of battery high rate performance.

Chinese patent (notification number: CN101969112A) disclose a kind of preparation method of negative material, be 100:(0.1～5 in mass ratio with negative material and catalyst) after the mechanical mixture, add in the thermal reaction apparatus, pass to carbon-source gas, and pass to protective gas as carrying source gas, cooling after being incubated 1～72 hour after being warmed up to 400～900 ℃, the mixture of formation negative material, catalyst and carbon nano-tube; Be 1:(1～100 with mixture and oxidant according to mass ratio again) add in the reactor, add water and stir into pastel; Again pastel is heated to 50～400 ℃ of lower reactions 1～20 hour, makes the composite negative pole material that is coated with carbon nano-tube.Yet the method course of reaction is complicated, the negative material less stable that makes, and the employing oxidation step can destroy the rock-steady structure of lithium titanate self, finally affects the cycle performance of battery.

Summary of the invention

The preparation method who the purpose of this invention is to provide a kind of lithium titanate/carbon/carbon nano tube composite negative pole material is to improve high rate performance and the cycle performance of battery.

In order to realize above purpose, the technical solution adopted in the present invention is:

A kind of preparation method of lithium titanate/carbon/carbon nano tube composite negative pole material; concrete steps are as follows: be that to add particle diameter in the lithium titanate powder of 0.3～10 μ m be the catalyst fines mixing of 30～100nm at particle diameter; mixed-powder is heated to 600～800 ℃ under atmosphere of hydrogen; be to pass into acetylene gas under 800～1200 ℃ in temperature then; constant temperature is 24～48 hours again; product behind the constant temperature is cooled to room temperature under inert gas shielding, removes catalyst and get final product.

Described catalyst is iron, cobalt, nickel, ferric nitrate, nickel nitrate, iron chloride or nickel chloride.

The weight ratio of described lithium titanate powder and catalyst is lithium titanate powder: catalyst=10:(0.1～1).

Described inert gas is nitrogen, argon gas or helium.

Described lithium titanate powder can be prepared by a conventional method to obtain, and also can be the commercial goods.The present invention only provides a kind of concrete method for preparing lithium titanate powder; step is as follows: be lithium according to mol ratio: titanium: dispersant=1:(1.2 ~ 2): (3～8) get lithium source, titanium source and dispersant; ball milling to particle size is 0.5～5 μ m behind the mixing; dry; under inert gas shielding dried powder being calcined 1～48 hour under 600～1000 ℃, is that 0.3～10 μ m namely gets lithium titanate powder with powder ball milling to the granularity after the calcining.

Described lithium source is lithium carbonate, lithium acetate, lithium nitrate or lithium hydroxide.

Described titanium source is titanium dioxide.

Described dispersant is absolute ethyl alcohol.

Beneficial effect of the present invention:

The present invention adopts chemical vapour deposition technique in lithium titanate superficial growth carbon nano-tube, its with directly in lithium titanate doped carbon nanometer pipe compare and have the characteristic such as be uniformly dispersed, adhesion is strong, the carbon nano-tube of growth is easier simultaneously forms network configuration on the lithium titanate surface, and the Stability Analysis of Structures that improves battery material under large multiplying power discharging condition is played an important role.

Lithium ion battery of the present invention by utilizing carbon nano-tube high conductivity and the network configuration of formation to improve the contact probability with lithium titanate, reduce internal resistance, reduce polarization, the larger specific area of carbon nano-tube can improve again the imbibition liquid-keeping property of negative material simultaneously, thereby improves the large multiplying power discharging ability of battery and the circulation ability of battery.

In a word, the composite negative pole material that adopts chemical vapour deposition technique to prepare in lithium titanate superficial growth carbon nano-tube, can improve conductivity and the large multiplying power discharging ability of lithium titanate, can improve again imbibition ability and the cyclical stability of battery, preferably impetus has been played in the extensive use of lithium titanate negative material; And the preparation method is simple, quick, good stability, and cost is low, is suitable for large-scale production and application.

Description of drawings

Fig. 1 is the Electronic Speculum figure of the embodiment of the invention 1 preparation negative material;

Fig. 2 is the multiplying power discharging figure of lithium ion battery among the embodiment 1;

Fig. 3 is the cyclic curve figure of lithium ion battery in embodiment and the Comparative Examples.

Embodiment

Below in conjunction with specific embodiment the present invention is described in further detail, but does not consist of any limitation of the invention.

Embodiment 1

The lithium titanate/carbon/carbon nano tube composite negative pole material prepares by following method in the present embodiment, and concrete steps are:

(1) preparation of lithium titanate powder: be lithium according to mol ratio: titanium: dispersant=1:1.2:5 gets lithium carbonate, titanium dioxide and absolute ethyl alcohol, mix in the rear adding planetary ball mill, rotating speed wet ball grinding take 400 rev/mins of speed obtained particle diameter in 48 hours as 2 μ m powder, withpowder 100 ℃ of lower freeze-day with constant temperature 2 hours, under argon shield, dried powder was calcined 12 hours under 800 ℃, powder after the calcining is cooled to 100 ℃ of lower taking-ups, adds again that the rotating speed ball milling take 1000 rev/mins namely got particle diameter in 120 minutes as the lithium titanate powder of 1 μ m in the ultra-fine ball mill;

(2) be that to add particle diameter in the lithium titanate powder of 2 μ m be that the iron catalyst mixing of 50nm gets mixed-powder at step (1) particle diameter, the weight ratio of described lithium titanate powder and iron is lithium titanate powder: iron=10:0.5, mixed-powder is added in the quartz tube reactor, and in described reactor, pass into hydrogen, speed with 10 ℃/minute in passing into the process of hydrogen rises to 600 ℃ with the temperature in the reactor, be to pass into acetylene gas under 800℃ 100 minutes in temperature then, constant temperature 24 hours, product in the constant temperature post-reactor is cooled to room temperature under nitrogen atmosphere, afterwards through concentrated sulfuric acid washing, distilled water washing, 80 ℃ of dryings after 6 hours ball milling namely get the lithium titanate/carbon/carbon nano tube composite negative pole material.Surface Electronic Speculum figure sees Fig. 1 for details.

The negative material of the present embodiment lithium ion adopts the above-mentioned lithium titanate/carbon/carbon nano tube composite negative pole material for preparing, and positive electrode is the battery LiFePO4, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1,2 for details, and multiplying power discharging figure and cyclic curve see Fig. 2, Fig. 3 for details.

Embodiment 2

The lithium titanate/carbon/carbon nano tube composite negative pole material prepares by following method in the present embodiment, and concrete steps are:

(1) preparation of lithium titanate powder: be lithium according to mol ratio: titanium: dispersant=1:2:3 gets lithium nitrate, titanium dioxide and absolute ethyl alcohol, mix in the rear adding planetary ball mill, rotating speed wet ball grinding take 400 rev/mins of speed obtained particle diameter in 48 hours as 5 μ m powder, withpowder 100 ℃ of lower freeze-day with constant temperature 3 hours, under nitrogen protection, dried powder was calcined 24 hours under 1000 ℃, powder after the calcining is cooled to 100 ℃ of lower taking-ups, adds again that the rotating speed ball milling take 2000 rev/mins namely got particle diameter in 300 minutes as the lithium titanate powder of 3 μ m in the ultra-fine ball mill;

(2) be that to add particle diameter in the lithium titanate powder of 3 μ m be that the Co catalysts mixing of 100nm gets mixed-powder at step (1) particle diameter, the weight ratio of described lithium titanate powder and cobalt is lithium titanate powder: cobalt=10:1, mixed-powder is added in the quartz tube reactor, and in described reactor, pass into hydrogen, speed with 20 ℃/minute in passing into the process of hydrogen rises to 800 ℃ with the temperature in the reactor, be to pass into acetylene gas under 1000℃ 200 minutes in temperature then, constant temperature 24 hours, product in the constant temperature post-reactor is cooled to room temperature under nitrogen atmosphere, afterwards through concentrated sulfuric acid washing, distilled water washing, 80 ℃ of dryings after 6 hours ball milling namely get the lithium titanate/carbon/carbon nano tube composite negative pole material.

The negative material of the present embodiment lithium ion adopts the above-mentioned lithium titanate/carbon/carbon nano tube composite negative pole material for preparing, and positive electrode is the battery LiFePO4, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1 for details, and cyclic curve sees Fig. 3 for details.

Embodiment 3

The lithium titanate/carbon/carbon nano tube composite negative pole material prepares by following method in the present embodiment, and concrete steps are:

(1) preparation of lithium titanate powder: be lithium according to mol ratio: titanium: dispersant=1:2:8 gets lithium acetate, titanium dioxide and absolute ethyl alcohol, mix in the rear adding planetary ball mill, rotating speed wet ball grinding take 400 rev/mins of speed obtained particle diameter in 48 hours as 0.5 μ m powder, withpowder 100 ℃ of lower freeze-day with constant temperature 4 hours, under the helium protection, dried powder was calcined 48 hours under 600 ℃, powder after the calcining is cooled to 100 ℃ of lower taking-ups, adds again that the rotating speed ball milling take 1500 rev/mins namely got particle diameter in 200 minutes as the lithium titanate powder of 0.3 μ m in the ultra-fine ball mill;

(2) be that to add particle diameter in the lithium titanate powder of 0.3 μ m be that the Raney nickel mixing of 30nm gets mixed-powder at step (1) particle diameter, the weight ratio of described lithium titanate powder and nickel is lithium titanate powder: nickel=10:0.1, mixed-powder is added in the quartz tube reactor, and in described reactor, pass into hydrogen, speed with 20 ℃/minute in passing into the process of hydrogen rises to 600 ℃ with the temperature in the reactor, be to pass into acetylene gas under 900℃ 50 minutes in temperature then, constant temperature 48 hours, product in the constant temperature post-reactor is cooled to room temperature under nitrogen atmosphere, afterwards through concentrated sulfuric acid washing, distilled water washing, 60 ℃ of dryings after 8 hours ball milling namely get the lithium titanate/carbon/carbon nano tube composite negative pole material.

The negative material of the present embodiment lithium ion adopts the above-mentioned lithium titanate/carbon/carbon nano tube composite negative pole material for preparing, and positive electrode is the battery LiFePO4, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1 for details, and cyclic curve sees Fig. 3 for details.

Embodiment 4

The lithium titanate/carbon/carbon nano tube composite negative pole material prepares by following method in the present embodiment, and concrete steps are:

(1) preparation of lithium titanate powder: be lithium according to mol ratio: titanium: dispersant=1:1.2:8 gets lithium hydroxide, titanium dioxide and absolute ethyl alcohol, mix in the rear adding planetary ball mill, rotating speed wet ball grinding take 400 rev/mins of speed obtained particle diameter in 48 hours as 0.5 μ m powder, withpowder 100 ℃ of lower freeze-day with constant temperature 1 hour, under argon shield, dried powder was calcined 30 hours under 700 ℃, powder after the calcining is cooled to 100 ℃ of lower taking-ups, adds again that the rotating speed ball milling take 2000 rev/mins namely got particle diameter in 200 minutes as the lithium titanate powder of 1 μ m in the ultra-fine ball mill;

(2) be that to add particle diameter in the lithium titanate powder of 1 μ m be that the ferric nitrate catalyst mixing of 50nm gets mixed-powder at step (1) particle diameter, the weight ratio of described lithium titanate powder and ferric nitrate is lithium titanate powder: ferric nitrate=10:0.3, mixed-powder is added in the quartz tube reactor, and in described reactor, pass into hydrogen, speed with 10 ℃/minute in passing into the process of hydrogen rises to 1000 ℃ with the temperature in the reactor, be to pass into acetylene gas under 850 ℃ 300 minutes in temperature then, constant temperature 1 hour, product in the constant temperature post-reactor is cooled to room temperature under nitrogen atmosphere, afterwards through concentrated sulfuric acid washing, distilled water washing, 60 ℃ of dryings after 8 hours ball milling namely get the lithium titanate/carbon/carbon nano tube composite negative pole material.

The negative material of the present embodiment lithium ion adopts the above-mentioned lithium titanate/carbon/carbon nano tube composite negative pole material for preparing, and positive electrode is the battery LiFePO4, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1 for details, and cyclic curve sees Fig. 3 for details.

Embodiment 5

The lithium titanate/carbon/carbon nano tube composite negative pole material prepares by following method in the present embodiment, and concrete steps are:

(1) preparation of lithium titanate powder: be lithium according to mol ratio: titanium: dispersant=1:1.2:3 gets lithium hydroxide, titanium dioxide and absolute ethyl alcohol, mix in the rear adding planetary ball mill, rotating speed wet ball grinding take 400 rev/mins of speed obtained particle diameter in 48 hours as 5 μ m powder, withpowder 100 ℃ of lower freeze-day with constant temperature 4 hours, under argon shield, dried powder was calcined 30 hours under 700 ℃, powder after the calcining is cooled to 100 ℃ of lower taking-ups, adds again that the rotating speed ball milling take 2000 rev/mins namely got particle diameter in 200 minutes as the lithium titanate powder of 10 μ m in the ultra-fine ball mill;

(2) be that to add particle diameter in the lithium titanate powder of 10 μ m be that the nickel chloride iron catalyst mixing of 80nm gets mixed-powder at step (1) particle diameter, the weight ratio of described lithium titanate powder and nickel chloride is lithium titanate powder: nickel chloride=10:0.5, mixed-powder is added in the quartz tube reactor, and in described reactor, pass into hydrogen, speed with 10 ℃/minute in passing into the process of hydrogen rises to 800 ℃ with the temperature in the reactor, be to pass into acetylene gas under 1000℃ 60 minutes in temperature then, constant temperature 24 hours, product in the constant temperature post-reactor is cooled to room temperature under nitrogen atmosphere, afterwards through concentrated sulfuric acid washing, distilled water washing, 60 ℃ of dryings after 8 hours ball milling namely get the lithium titanate/carbon/carbon nano tube composite negative pole material.

The negative material of the present embodiment lithium ion adopts the above-mentioned lithium titanate/carbon/carbon nano tube composite negative pole material for preparing, and positive electrode is the battery LiFePO4, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1 for details, and cyclic curve sees Fig. 3 for details.

Comparative Examples 1

The positive electrode of this Comparative Examples lithium ion is pure lithium titanate, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1 for details, and cyclic curve sees Fig. 3 for details.

Comparative Examples 2

The lithium titanate/carbon/carbon nano tube composite negative pole material prepares by following method in this Comparative Examples, and concrete steps are:

(1) preparation of lithium titanate powder: be lithium according to mol ratio: titanium: dispersant=1:1.2:3 gets lithium hydroxide, titanium dioxide and absolute ethyl alcohol, mix in the rear adding planetary ball mill, rotating speed wet ball grinding take 400 rev/mins of speed obtained particle diameter in 48 hours as 5 μ m powder, withpowder 100 ℃ of lower freeze-day with constant temperature 10 hours, under argon shield, dried powder was calcined 30 hours under 700 ℃, powder after the calcining is cooled to 100 ℃ of lower taking-ups, adds again that the rotating speed ball milling take 2000 rev/mins namely got particle diameter in 200 minutes as the lithium titanate powder of 10 μ m in the ultra-fine ball mill;

(2) be that to add particle diameter in the lithium titanate powder of 10 μ m be that the nickel chloride iron catalyst mixing of 80nm gets mixed-powder at step (1) particle diameter, the weight ratio of described lithium titanate powder and nickel chloride is lithium titanate powder: nickel chloride=10:0.5, mixed-powder is added in the quartz tube reactor, and in described reactor, pass into hydrogen, speed with 10 ℃/minute in passing into the process of hydrogen rises to 800 ℃ with the temperature in the reactor, be to pass into acetylene gas under 1000℃ 60 minutes in temperature then, constant temperature 24 hours, product in the constant temperature post-reactor is cooled to room temperature under nitrogen atmosphere, again according to quality than product: concentrated hydrochloric acid, add water after the mixed acid of hydrofluoric acid=1:50 mixes and stir into starchiness, programming rate with 5 ℃/min is heated to 300 ℃ of reactions 5 hours, in course of reaction, stirred once every 1 hour, after with the starchiness thing move under the rotating speed of 300r/min, continue in the centrifuge washing equipment to add water washing to the pH of slurry for neutral, centrifugal dehydration makes moisture be lower than 40%, dries to moisture to be lower than 0.01% and get final product under 100 ℃ again.

The negative material of this Comparative Examples lithium ion adopts the above-mentioned lithium titanate/carbon/carbon nano tube composite negative pole material for preparing, and positive electrode is the battery LiFePO4, and electrolyte is 1.0mol/L LiPF₆/ EC+DEC(V_EC: V_DEC=1: 1) (EC: ethylene carbonate, DEC: diethyl carbonate), barrier film is U.S. Celgard2300 barrier film, and the performance of the 2.5AH lithium ion battery that makes sees following table 1 for details, and cyclic curve sees Fig. 3 for details.

The comparison of lithium ion battery high rate performance in table 1 embodiment and the Comparative Examples

The comparison of cycle performance of lithium ion battery in table 2 embodiment and the Comparative Examples

Claims (7)

Translated fromChinese

1.一种钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：具体步骤如下：在粒径为0.3～10μm的钛酸锂粉末中加入粒径为30～100nm的催化剂粉末混匀，将混合粉末在氢气氛围下加热至600～800℃，而后在温度为800～1200℃下通入乙炔气体，再恒温24～48小时，将恒温后的产物在惰性气体保护下冷却至室温，去除催化剂即得。1. A preparation method for a lithium titanate/carbon nanotube composite negative electrode material, characterized in that: the specific steps are as follows: adding a catalyst powder mixed with a particle diameter of 30 to 100 nm in lithium titanate powder with a particle diameter of 0.3 to 10 μm Evenly, heat the mixed powder to 600-800°C in a hydrogen atmosphere, then pass acetylene gas at a temperature of 800-1200°C, keep the temperature for 24-48 hours, and cool the product after constant temperature to room temperature under the protection of inert gas , remove the catalyst that is.2.根据权利要求1所述的钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：所述的催化剂为铁、钴、镍、硝酸铁、硝酸镍、氯化铁或氯化镍。2. the preparation method of lithium titanate/carbon nanotube composite negative electrode material according to claim 1 is characterized in that: described catalyst is iron, cobalt, nickel, iron nitrate, nickel nitrate, iron chloride or chloride nickel.3.根据权利要求1所述的钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：所述的钛酸锂粉末与催化剂的重量比为钛酸锂粉末:催化剂=10:（0.1～1）。3. the preparation method of lithium titanate/carbon nanotube composite negative electrode material according to claim 1, is characterized in that: the weight ratio of described lithium titanate powder and catalyzer is lithium titanate powder:catalyst=10:( 0.1～1).4.根据权利要求1-3任一项所述的钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：所述钛酸锂粉末的制备步骤如下：按照摩尔比为锂:钛:分散剂=1:（1.2~2）:（3～8）取锂源、钛源及分散剂，混匀后球磨至粉末粒度为0.5～5μm，干燥，在惰性气体保护下将干燥后的粉末在600～1000℃下煅烧1～48小时，将煅烧后的粉末球磨至粒度为0.3～10μm即得钛酸锂粉末。4. according to the preparation method of lithium titanate/carbon nanotube composite negative electrode material described in any one of claim 1-3, it is characterized in that: the preparation step of described lithium titanate powder is as follows: lithium according to molar ratio: titanium : Dispersant = 1: (1.2~2): (3~8) Take lithium source, titanium source and dispersant, mix and ball mill until the powder particle size is 0.5~5μm, dry, and dry the dried powder under the protection of inert gas The powder is calcined at 600-1000° C. for 1-48 hours, and the calcined powder is ball-milled to a particle size of 0.3-10 μm to obtain lithium titanate powder.5.根据权利要求4所述的钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：所述的锂源为碳酸锂、乙酸锂、硝酸锂或氢氧化锂。5. The preparation method of lithium titanate/carbon nanotube composite negative electrode material according to claim 4, characterized in that: the lithium source is lithium carbonate, lithium acetate, lithium nitrate or lithium hydroxide.6.根据权利要求4所述的钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：所述的钛源为二氧化钛。6. The preparation method of lithium titanate/carbon nanotube composite negative electrode material according to claim 4, characterized in that: the titanium source is titanium dioxide.7.根据权利要求4所述的钛酸锂/碳纳米管复合负极材料的制备方法，其特征在于：所述的分散剂为无水乙醇。7. The preparation method of lithium titanate/carbon nanotube composite negative electrode material according to claim 4, characterized in that: the dispersant is absolute ethanol.

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