A kind of preparation method of negative electrode of lithium ion battery Si-C composite material
Technical field
The present invention relates to a kind of preparation methods of lithium ion battery negative material.Specifically, the present invention provides one kind
The preparation method of Si-C composite material.
Background technique
Lithium ion battery is that nineteen ninety Sony Corporation of Japan develops and starts to realize that a kind of high-efficiency energy-storage of commercialization produces
Product, compared with other batteries, the advantages of lithium ion battery, is open-circuit voltage height, and commercial battery is mostly 3.6V and ni-mh and ni-Cd
The open-circuit voltage of secondary cell is 1.2V;Specific capacity is big, is 2.5 times of ni-Cd secondary cell, is the 1.5 of nickel-hydrogen secondary cell
Times;Self-discharge rate is low, and less than 8%/moon, far below 30%/moon of nickel-cadmium cell and 40%/moon of nickel-metal hydride battery, the service life is long, leads to
It can often reach thousand times or more, and there is no memory effect, these advantages make lithium ion battery welcomed by the people.
In order to better meet the demand for development of lithium ion battery, high-performance, low cost novel positive and negative electrode material grind
Studying carefully is the key that lithium secondary battery development.Commercialized lithium ion battery majority samples natural or artificial graphite conduct at present
Negative electrode material, but the theoretical capacity of graphite itself is relatively low (being less than 400mAh/g), silicon has as negative electrode material
The theoretical capacity of 4200mAh/g is far longer than the graphite type material of present commercialization, how to efficiently use silicon-based anode material in recent years
The research of material is more and more.But pure simple substance silicon can not be used as electrode material, because its conductivity is low, silicon is semiconductor material
Material, conductivity only have 6.7*10-4S/cm, on the other hand in battery charge and discharge process, the silicon as negative electrode material can generate huge
Big volume expansion causes negative electrode material and negative current collector to be detached from, and cycle performance of battery is unable to satisfy commercial requirement.For with
Upper two aspects problem, common practice is to be mixed using silicon with Carbon materials in industry, i.e. Si-C composite material, utilizes Carbon materials
Good electric conductivity solves the problems, such as the conductivity of elemental silicon, on the other hand the smaller ratio for reducing silicon in Si-C composite material,
Reduce the size of silicon, such as using nano-silicon, reduces the bulking effect of material entirety.The complex method of Si-C composite material has very
A variety of, solid phase is compound and the method for the compound high temperature sintering again of liquid phase is more, and gaseous recombination is because for equipment requirement height,
Technique is more difficult to control and less to appear in the newspapers.But gaseous recombination also has significant benefit, such as cries and be easy to get nano-silicon, obtains
Nano-silicon carbon-based material dispersion more evenly.
Patent CN104103821B discloses a kind of method that gas phase prepares Si-C composite material, includes the following steps: 1)
Catalyst is placed in chemical vapor deposition reaction chamber;2) heating chemical phase depositing reaction chamber, toward chemical vapour deposition reaction
Interior is passed through reacting gas source and carrier gas, the process that the Si-SiOx generated in chemical gas phase reaction process is passed through dynamic rotary
The carbon base body of carboxylated processing, is made the presoma of silicon-carbon cathode material;3) organic pyrolysis carbon coating is carried out to presoma to handle,
Then calcining obtains silicon-carbon cathode material in nonoxidizing atmosphere.The invention conductivity is high, and silicon dispersibility in negative electrode material is good
It is good.But this method can not effectively control the problem of growing up of Si particle in chemical vapor deposition processes, if vapor deposition reaction
Overlong time, the size of Si particle can be more than nanoscale, excessive, and the Volumetric expansion of Si is still in battery charge and discharge process
Very big, the poor circulation of battery, if the vapor deposition reaction time shortens, the Si ratio effectively in deposition is too small, then capacity
It is small, can not Si-C composite material capacity advantage.
Patent CN102637874B disclose Si-C composite material the preparation method comprises the following steps: on different carbon material matrixes, adopt
High temperature vapor deposition is carried out with silicon-carbon organic precursor, by adjusting reaction condition parameter, the silicon-carbon for obtaining function admirable is compound
Negative electrode material.Silicon-carbon composite cathode material structure alleviates silicon in charge and discharge process because of the machinery of volume expansion and contraction generation
Stress eliminates bulk effect, and the silicon-carbon composite cathode material production cost is low, simple process, is suitable for industrialized production, silicon-carbon
Composite material is conducive to fast charging and discharging process, and improves the specific capacity and cyclical stability of material, during initial charge
The quality and structure of solid electrolyte film can be optimized, realizing reduces irreversible capacity for the first time.But this method can only pass through gas
Mutually the length of time of deposition controls the size of silicon particle, and vapor deposition times are long, then silicon particle is excessive, electrochemistry charge and discharge process
Middle available capacity is small;In order to control silicon particle, shorter vapor deposition times can only be taken, then the silicon weight mistake effectively in deposition
It is small, the advantage of silicon high capacity can not be played.
Patent CN201610908385.0 discloses a kind of for the silica-base material of negative electrode of lithium ion battery and its preparation side
Method, the business silicon powder that diameter is 50-100nm is placed in chemical vapor deposition (CVD) tube furnace by (1), directly in business silicon powder
Surface prepares graphene, 30~60min of time of graphene growth by CVD method, and growth pressure is normal pressure or low pressure
(0.1Pa), temperature are 900 DEG C to 1200 DEG C, and the number of plies of graphene is 1~10;(2) Si@Gra obtained in step (1) is multiple
Object ultrasonic disperse 20 minutes in ethanol are closed, Si@Gra alcohol mixed solution is formed;(3) by Si@Gra obtained in step (2)
Alcohol mixed solution layer assembly is on metal foam, after ethyl alcohol volatilization, obtains the graphene coated of metal foam support
Nano silicon-based lithium ion battery negative material.The material electrochemical performance of the invention is stablized, and battery can stablize 5000 circle of circulation,
The high rate performance of the good conductivity of electrode, battery is excellent, and charge and discharge still have~600mAh g-1 at current density 50Ag-1
Capacity.The reversible of battery is acted charitably, cyclic voltammetry curve overlapping.But this method uses diameter for the business silicon powder of 50-100nm,
Directly by nanoscale silicon powder be put into chemical vapor deposition (CVD) tube furnace high temperature processing, due to Nano grade silicon powder very
Hold and reunite, although individual particle is Nano grade, due to the very high surface energy of nano material, individual particle is easily agglomerated into greatly
Particle, therefore it is difficult in final product the silicon particle there are Nano grade, little particle silicon, which generates, reduces material in charge and discharge
The advantage that Volumetric expansion is reduced in journey is difficult to embody.
Summary of the invention
In view of the deficiencies of the prior art, the object of the present invention is to provide the preparations of negative electrode of lithium ion battery Si-C composite material
Method.Negative electrode of lithium ion battery Si-C composite material is prepared using the method for vapor deposition, by carbon-based bottom material repeatedly
Alternate vapor deposition Si and carbon, control ventilation sequence and time, obtain nanoscale Si deposition on the carbon material, while in Si material
One layer of carbon material of deposition cladding on material, deposition carbon can be when next round be vapor-deposited Si, and prevention is deposited on last round of shape
At Si particle on, prevent Si particle growth, and increase the electric conductivity of material.
The present invention is achieved by the following technical solutions:
The present invention provides a kind of preparation methods of negative electrode of lithium ion battery Si-C composite material, comprising the following steps:
(1) it carbon-based 50~1000g of bottom material, is put into Equipment for Heating Processing, vapor deposition temperature is set in 500~1650
℃;
(2) be passed through gaseous organosilicon alkane or organosilan and gaseous carbon source mixture (flow-rate ratio 1: 0.1~1:
10), duration 5-120min, flow 0.1-20L/min;
(3) stop being passed through gaseous organosilicon alkane, start to be passed through gaseous carbon source, duration 5-120min, flow 0.1-
20L/min;
(4) step 2 and 3 is repeated, 1-20 wheel is repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
The carbon-based bottom material are as follows: natural graphite, artificial graphite, carbonaceous mesophase spherules, carbon nanotube, graphene, carbon fiber
The composition of one or more of dimension;
The gaseous organosilicon alkane is SiH4、SiH3R、SiH2R2、SiHR3One or more of, wherein R be CH3 or
CH2CH3 or OCH3Or OCH2CH3。
The gaseous carbon source is a combination of one or more object of alkane, alkene, alkynes, aromatic hydrocarbon, ethers, preferably
For acetylene.
The Equipment for Heating Processing are as follows: tube furnace, batch-type furnace, board-like furnace or high-temperature rotary furnace, preferably high-temperature rotary furnace;
Preferably, the vapor deposition temperature is 650~1450 DEG C.
Preferably, the mixture (flow of gaseous organosilicon alkane or organosilan and gaseous carbon source is passed through in the step 2
Than for 1: 0.1~1: 10), and duration 5-100min.
Preferably, the gaseous organosilicon alkane is SiH4、SiH3CH3。
The present invention has the advantages that compared with prior art
(1) preparation method of negative electrode of lithium ion battery Si-C composite material of the present invention obtains nanoscale Si deposition
After on carbon-based bottom material, stop the vapor deposition of Si, be changed to the vapor deposition of only carbon, obtained effect is so that Si material
Surface deposition one layer of carbon material of cladding, deposition carbon can be when next round be vapor-deposited Si, and prevention is deposited on last round of shape
At Si particle on, cut off the path of growing up of Si particle, prevent Si particle growth, Si is in the Si-C composite material finally obtained
Nanoscale, with the material prepare lithium ion battery charge and discharge process in, volume expansion is small, and cycle performance is excellent;
(2) method that the present invention uses alternate vapor deposition Si and carbon, Si particle surface deposition have coated one layer of carbon, have obtained
Materials conductive performance it is more preferable;
(3) present invention is heat-treated using high-temperature rotary furnace, and solid matter is constantly mixed during the reaction, Si
Or carbon vapor deposition is uniform, the phenomenon that being less prone to deposition Si or deposit carbon enrichment;
(4) step of the present invention is simple, is easy to industrialization.
(5) when selecting acetylene as gaseous carbon source, the efficiency highest for the carbon that is vapor-deposited.
Specific embodiment
Present invention will be further explained below with reference to specific examples.It should be understood that these embodiments be only used for the present invention without
For limiting the scope of the invention.Externally it should be understood that after reading the contents of the present invention, those skilled in the art are to this hair
Bright to make various changes or modifications, these equivalent forms also fall within the scope of the appended claims of the present application.
Embodiment 1
(1) it carbonaceous mesophase spherules 100g, is put into high-temperature rotary furnace, vapor deposition temperature is set in 1200 DEG C;
(2) it is passed through SiH4, duration 5min, flow 1L/min;
(3) stop being passed through SiH4, start to be passed through acetylene, duration 10min, flow 1L/min;
(4) step 2 and 3 is repeated, 10 wheels are repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
Performance evaluation, simulated battery production:
For the negative electrode of lithium ion battery Si-C composite material for using embodiment to prepare respectively as active material, production simulation is electric
Pond, making step are as follows:
A, ingredient and mechanical stirring, according to active material 3.4g, conductive agent 0.2g (is not needed then) with the presence of carbon black situation,
The ratio of 5% Kynoar PVDF 8g and N-Methyl pyrrolidone NMP 0.8g weighs active material, conductive agent, 5%
PVDF and NMP, then mechanical stirring mode is used to be configured to solid content as 32.26% slurry, stir about 15min, slurry is in bee
Honey ointment shape is preferably.
B, slurry is coated on copper foil, makes pole piece.
C, pole piece dries drying, is placed directly in air dry oven, and 95~100 DEG C are toasted 2 hours, and it is dry to be then placed in vacuum
Dry case, 95~100 DEG C vacuum drying 10 hours.
D, assembled battery, makees cathode with lithium piece, makees diaphragm with polypropylene or polyethylene, with 1mol/L LiPF6 (volume ratio
Ethylene carbonate and dimethyl carbonate mixed liquor for 1: 1) it is used as electrolyte, it is assembled into simulated battery.
E, simulation electricity is measured using the blue electric battery test system of the LAND type of the CT2001C of Wuhan Jin Nuo Electronics Co., Ltd.
The data in pond, voltage range are 0.005~2.0V, and charging and discharging currents are the chemical property that 0.2C evaluates material.Reversible capacity
For 460mAh/g, efficiency for charge-discharge 87%, circulation is after 25 weeks, capacity retention ratio 97%.
Embodiment 2
(1) it artificial graphite 50g, is put into tube furnace, vapor deposition temperature is set in 1650 DEG C;
(2) it is passed through SiH3CH3With normal butane (flow-rate ratio 1: 1), duration 100min, flow 0.1L/min;
(3) stop being passed through SiH3CH3And normal butane, start to be passed through acetylene, duration 5min, flow 10L/min;
(4) step 2 and 3 is repeated, 2 wheels are repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
Performance evaluation, simulated battery production:
For the negative electrode of lithium ion battery Si-C composite material for using embodiment to prepare respectively as active material, production simulation is electric
Pond, making step are as follows:
A, ingredient and mechanical stirring, according to active material 3.4g, conductive agent 0.2g (is not needed then) with the presence of carbon black situation,
The ratio of 5% Kynoar PVDF 8g and N-Methyl pyrrolidone NMP 0.8g weighs active material, conductive agent, 5%
PVDF and NMP, then mechanical stirring mode is used to be configured to solid content as 32.26% slurry, stir about 15min, slurry is in bee
Honey ointment shape is preferably.
B, slurry is coated on copper foil, makes pole piece.
C, pole piece dries drying, is placed directly in air dry oven, and 95~100 DEG C are toasted 2 hours, and it is dry to be then placed in vacuum
Dry case, 95~100 DEG C vacuum drying 10 hours.
D, assembled battery, makees cathode with lithium piece, makees diaphragm with polypropylene or polyethylene, with 1mol/L LiPF6 (volume ratio
Ethylene carbonate and dimethyl carbonate mixed liquor for 1: 1) it is used as electrolyte, it is assembled into simulated battery.
E, simulation electricity is measured using the blue electric battery test system of the LAND type of the CT2001C of Wuhan Jin Nuo Electronics Co., Ltd.
The data in pond, voltage range are 0.005~2.0V, and charging and discharging currents are the chemical property that 0.2C evaluates material.Reversible capacity
For 550mAh/g, efficiency for charge-discharge 84%, circulation is after 25 weeks, capacity retention ratio 90%.
Embodiment 3
(1) it natural graphite 1000g, is put into high-temperature rotary furnace, vapor deposition temperature is set in 650 DEG C;
(2) it is passed through SiH3OCH3, duration 20min, flow 0.5L/min;
(3) stop being passed through SiH3OCH3, start to be passed through ethylene, duration 30min, flow 0.5L/min;
(4) step 2 and 3 is repeated, 20 wheels are repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
Performance evaluation, simulated battery production:
For the negative electrode of lithium ion battery Si-C composite material for using embodiment to prepare respectively as active material, production simulation is electric
Pond, making step are as follows:
A, ingredient and mechanical stirring, according to active material 3.4g, conductive agent 0.2g (is not needed then) with the presence of carbon black situation,
The ratio of 5% Kynoar PVDF 8g and N-Methyl pyrrolidone NMP 0.8g weighs active material, conductive agent, 5%
PVDF and NMP, then mechanical stirring mode is used to be configured to solid content as 32.26% slurry, stir about 15min, slurry is in bee
Honey ointment shape is preferably.
B, slurry is coated on copper foil, makes pole piece.
C, pole piece dries drying, is placed directly in air dry oven, and 95~100 DEG C are toasted 2 hours, and it is dry to be then placed in vacuum
Dry case, 95~100 DEG C vacuum drying 10 hours.
D, assembled battery, makees cathode with lithium piece, makees diaphragm with polypropylene or polyethylene, with 1mol/L LiPF6 (volume ratio
Ethylene carbonate and dimethyl carbonate mixed liquor for 1: 1) it is used as electrolyte, it is assembled into simulated battery.
E, simulation electricity is measured using the blue electric battery test system of the LAND type of the CT2001C of Wuhan Jin Nuo Electronics Co., Ltd.
The data in pond, voltage range are 0.005~2.0V, and charging and discharging currents are the chemical property that 0.2C evaluates material.Reversible capacity
For 650mAh/g, efficiency for charge-discharge 81%, circulation is after 25 weeks, capacity retention ratio 88%.
Embodiment 4
(1) carbonaceous mesophase spherules 90g, carbon nanotube 10g are put into high-temperature rotary furnace, vapor deposition temperature is set in
1400℃;
(2) it is passed through SiH4, duration 5min, flow 1L/min;
(3) stop being passed through SiH4, start to be passed through acetylene, duration 10min, flow 1L/min;
(4) step 2 and 3 is repeated, 20 wheels are repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
Performance evaluation, simulated battery production:
For the negative electrode of lithium ion battery Si-C composite material for using embodiment to prepare respectively as active material, production simulation is electric
Pond, making step are as follows:
A, ingredient and mechanical stirring, according to active material 3.4g, conductive agent 0.2g (is not needed then) with the presence of carbon black situation,
The ratio of 5% Kynoar PVDF 8g and N-Methyl pyrrolidone NMP 0.8g weighs active material, conductive agent, 5%
PVDF and NMP, then mechanical stirring mode is used to be configured to solid content as 32.26% slurry, stir about 15min, slurry is in bee
Honey ointment shape is preferably.
B, slurry is coated on copper foil, makes pole piece.
C, pole piece dries drying, is placed directly in air dry oven, and 95~100 DEG C are toasted 2 hours, and it is dry to be then placed in vacuum
Dry case, 95~100 DEG C vacuum drying 10 hours.
D, assembled battery, makees cathode with lithium piece, makees diaphragm with polypropylene or polyethylene, with 1mol/L LiPF6 (volume ratio
Ethylene carbonate and dimethyl carbonate mixed liquor for 1: 1) it is used as electrolyte, it is assembled into simulated battery.
E, simulation electricity is measured using the blue electric battery test system of the LAND type of the CT2001C of Wuhan Jin Nuo Electronics Co., Ltd.
The data in pond, voltage range are 0.005~2.0V, and charging and discharging currents are the chemical property that 0.2C evaluates material.Reversible capacity
For 550mAh/g, efficiency for charge-discharge 84%, circulation is after 25 weeks, capacity retention ratio 95%.
Embodiment 5
(1) carbonaceous mesophase spherules 95g, graphene 5g are put into high-temperature rotary furnace, vapor deposition temperature is set in 1000
℃;
(2) it is passed through SiH4, duration 15min, flow 1L/min;
(3) stop being passed through SiH4, start to be passed through methane, duration 15min, flow 1L/min;
(4) step 2 and 3 is repeated, 8 wheels are repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
Performance evaluation, simulated battery production:
For the negative electrode of lithium ion battery Si-C composite material for using embodiment to prepare respectively as active material, production simulation is electric
Pond, making step are as follows:
A, ingredient and mechanical stirring, according to active material 3.4g, conductive agent 0.2g (is not needed then) with the presence of carbon black situation,
The ratio of 5% Kynoar PVDF 8g and N-Methyl pyrrolidone NMP 0.8g weighs active material, conductive agent, 5%
PVDF and NMP, then mechanical stirring mode is used to be configured to solid content as 32.26% slurry, stir about 15min, slurry is in bee
Honey ointment shape is preferably.
B, slurry is coated on copper foil, makes pole piece.
C, pole piece dries drying, is placed directly in air dry oven, and 95~100 DEG C are toasted 2 hours, and it is dry to be then placed in vacuum
Dry case, 95~100 DEG C vacuum drying 10 hours.
D, assembled battery, makees cathode with lithium piece, makees diaphragm with polypropylene or polyethylene, with 1mol/L LiPF6 (volume ratio
Ethylene carbonate and dimethyl carbonate mixed liquor for 1: 1) it is used as electrolyte, it is assembled into simulated battery.
E, simulation electricity is measured using the blue electric battery test system of the LAND type of the CT2001C of Wuhan Jin Nuo Electronics Co., Ltd.
The data in pond, voltage range are 0.005~2.0V, and charging and discharging currents are the chemical property that 0.2C evaluates material.Reversible capacity
For 520mAh/g, efficiency for charge-discharge 88%, circulation is after 25 weeks, capacity retention ratio 96%.
Embodiment 6
(1) carbonaceous mesophase spherules 90g, carbon fiber 10g are put into high-temperature rotary furnace, vapor deposition temperature is set in 900
℃;
(2) silicon ethane, duration 5min, flow 1L/min are passed through;
(3) stop being passed through silicon ethane, start to be passed through acetylene, duration 10min, flow 1L/min;
(4) step 2 and 3 is repeated, 2 wheels are repeated;
(5) reaction stops, and natural cooling is cooled to room temperature to get compound to negative electrode of lithium ion battery silicon-carbon of the present invention
Material.
Performance evaluation, simulated battery production:
For the negative electrode of lithium ion battery Si-C composite material for using embodiment to prepare respectively as active material, production simulation is electric
Pond, making step are as follows:
A, ingredient and mechanical stirring, according to active material 3.4g, conductive agent 0.2g (is not needed then) with the presence of carbon black situation,
The ratio of 5% Kynoar PVDF 8g and N-Methyl pyrrolidone NMP 0.8g weighs active material, conductive agent, 5%
PVDF and NMP, then mechanical stirring mode is used to be configured to solid content as 32.26% slurry, stir about 15min, slurry is in bee
Honey ointment shape is preferably.
B, slurry is coated on copper foil, makes pole piece.
C, pole piece dries drying, is placed directly in air dry oven, and 95~100 DEG C are toasted 2 hours, and it is dry to be then placed in vacuum
Dry case, 95~100 DEG C vacuum drying 10 hours.
D, assembled battery, makees cathode with lithium piece, makees diaphragm with polypropylene or polyethylene, with 1mol/L LiPF6 (volume ratio
Ethylene carbonate and dimethyl carbonate mixed liquor for 1: 1) it is used as electrolyte, it is assembled into simulated battery.
E, simulation electricity is measured using the blue electric battery test system of the LAND type of the CT2001C of Wuhan Jin Nuo Electronics Co., Ltd.
The data in pond, voltage range are 0.005~2.0V, and charging and discharging currents are the chemical property that 0.2C evaluates material.Reversible capacity
For 412mAh/g, efficiency for charge-discharge 90%, circulation is after 25 weeks, capacity retention ratio 96%.