A kind of lithium carbon compound cathode piece and preparation method thereof and lithium secondary battery
Technical field
The invention belongs to technical field of lithium ion more particularly to a kind of lithium carbon compound cathode piece and preparation method thereof,
With the lithium secondary battery for using the lithium carbon compound cathode piece.
Background technology
Lithium ion battery has the characteristics that energy density is high, has extended cycle life and environmental-friendly, is widely used to various
In consumer electronics product and electric vehicle, and good application prospect is shown in large-scale energy storage field.At present lithium from
The negative material of sub- battery is mostly graphite, since the theoretical specific capacity of graphite is limited so that lithium ion battery energy density carries
Height faces bottleneck.
Lithium anode is since with very high theoretical specific capacity (3861mAh/g), being used as cathode of lithium battery can carry
High battery energy density.But process that is embedded and deviating from occurs in graphite flake layer not with lithium ion when graphite cathode charge and discharge
Together, lithium anode in charge and discharge happens is that the process of chemical deposition and the dissolving of lithium, this deposition and course of dissolution meeting
Sizable volume change is brought, and nonuniform deposition can occur, Li dendrite is generated and punctures diaphragm, lead to the safe thing of short circuit
Therefore limit the commercial applications of lithium anode.
In order to solve the problems, such as the Li dendrite in lithium anode application, researcher is by metallic lithium surface
Reason, forms various protective layers, obtains certain effect.The Chinese invention patent application of Publication No. CN104966814A discloses
A kind of lithium anode of high security and preparation method thereof, this method use thickness to be protected for 0.02~0.2 μm of silicon substrate
Layer is vaporized on lithium powder porous electrode, and the safety of lithium anode is improved with this.In Publication No. CN106159200A
State's invention patent application discloses a kind of lithium anode with protective coating and its preparation and application, using assembling molecular layer
With inorganic fast ionic conductor layer in lithium anode active material layer surface construction solid electrolyte interface film, inhibition is reached with this
The purpose of Li dendrite.The Chinese invention patent application of Publication No. CN105489944A is disclosed does the complete of cathode using lithium metal
Solid state battery preparation method coats negative material thin layer to inhibit Li dendrite in metallic lithium surface.Publication No.
The Chinese invention patent application of CN105489845A discloses a kind of based on PVD preparation all-solid lithium-ion battery sheet metals
The method of lithium base cathode, in sheet metal lithium base negative material surface stringer coat of metal, to inhibit Li dendrite.It is public
The Chinese invention patent application that the number of opening is CN105280886A discloses lithium anode surface in situ processing method and application, leads to
The treatment fluid for crossing a small amount of phosphoric acid substance reacts the interface generated based on lithium phosphate with the passivation layer of lithium metal and its surface
Protective layer inhibits Li dendrite with this.The Chinese invention patent application of Publication No. CN105845891A discloses a kind of with double
The lithium anode of layer structure, the lithium anode are made of the surface coating of the metallic lithium layer of bottom and upper layer, and surface is covered
Cap rock is one or more of carbon material, polymer material and glass fibre.
The preparation method of the above lithium anode can inhibit Li dendrite to a certain extent, however lithium metal is in charge and discharge
The great variety that can lead to negative plate thickness is constantly deposited and dissolved in the process, is eventually led to protective layer rupture and is failed, and
The huge thickness change of negative plate can generate huge stress variation to battery leads to battery structure damage inactivation, negative using these
The security performance and cycle performance of secondary cell prepared by pole remain to be further improved.
Invention content
The purpose of the present invention is to provide one kind can inhibit Li dendrite, and can be to avoid pole piece thickness in charge and discharge process
Changed lithium carbon compound cathode piece and preparation method thereof, and a kind of lithium that security performance and cycle performance can be improved is provided
Secondary cell.
To achieve the goals above, the present invention takes following technical solution:
A kind of lithium carbon compound cathode piece, including collector have nitrating carbon material layer, the nitrating carbon on the collector
Lithium metal is embedded in the hole of material layer.
Further, the thickness of the nitrating carbon material layer is 1~100 μm.
Further, the nitrating carbon material is nitrogen-doped carbon nanometer pipe, nitrogen-doped graphene, the hard charcoal of N doping, nitrogen
One or more of the carbon fiber of the soft charcoal of doping, the activated carbon of N doping, N doping.
The preparation method of aforementioned lithium carbon compound cathode piece, includes the following steps:
Nitrating carbon material, binder and stirring solvent are configured to uniform slurry, are coated on collector;
Dry out solvent obtains the pole piece that nitrating carbon material layer is formed on collection liquid surface;
The embedding lithium in nitrating carbon material layer, makes lithium metal be embedded into the hole of nitrating carbon material layer.
Further, the dosage of nitrating carbon material accounts for 50% or more of dry material gross mass when configuring slurry.
Preferably, the dosage of nitrating carbon material is more than 80%.
Further, by vacuum vapour deposition or galvanoplastic in the nitrating carbon material layer embedding lithium.
Lithium secondary battery, including positive plate, negative plate and electrolyte, negative plate are using lithium made from aforementioned preparation process
Carbon compound cathode piece.
Further, positive active material used by the positive plate is LiFePO4 or cobalt acid lithium or nickel-cobalt-manganese ternary
Material or LiMn2O4 or nickel cobalt aluminium ternary material or nickel ion doped or lithium-rich manganese base material or sulphur carbon composite anode material.
By above technical scheme it is found that the present invention forms nitrating carbon material layer, N doping carbon materials therein on a current collector
Material is used as framework material, and lithium metal is embedded in the gap of framework material and forms lithium carbon composite, and framework material plays very well
Supporting role, can eliminate thickness change of the negative plate in charge and discharge process, reduce pole piece and answered because what thickness change generated
Become;The nitrating carbon material layer of specific thicknesses is set simultaneously, and the carbon material electric conductivity of N doping is higher than common carbon material, and nitrogen is mixed
The compatibility of miscellaneous carbon material and lithium metal be higher than common carbon material, can induce lithium metal on framework material it is uniform at
Core inhibits Li dendrite, prevents battery short circuit.The negative plate of the present invention is applied to improve the peace of battery in lithium secondary battery
Full performance and cycle performance.
Description of the drawings
Fig. 1 is the structural schematic diagram of lithium carbon compound cathode of the present invention.
The specific implementation mode of the present invention is described in more detail below in conjunction with attached drawing
Specific implementation mode
In order to which above and other objects of the present invention, feature and advantage can be become apparent from, the embodiment of the present invention cited below particularly,
It is described below in detail.
As shown in Figure 1, the lithium carbon compound cathode piece of the present invention includes:Collector 1 is coated on mixing on 1 surface of collector
Nitrogen carbon material layer 2, the lithium metal 3 being embedded in 2 hole of nitrating carbon material layer.Preparation method is as follows:
Nitrating carbon material, binder and stirring solvent are configured to uniform slurry, are coated on collector 1;
The pole piece that 1 surface of collector is formed with nitrating carbon material layer 2 is obtained after dry out solvent;
By vacuum vapour deposition or galvanoplastic in nitrating carbon material layer 2 embedding lithium, so that lithium metal 3 is embedded into nitrating carbon material
In the hole of layer 2.
The thickness of nitrating carbon material layer 2 can be 1~100 μm, and nitrating carbon material can be nitrogen-doped carbon nanometer pipe, N doping
One or more of the carbon fiber of graphene, the hard charcoal of N doping, the soft charcoal of N doping, the activated carbon of N doping, N doping.
The slurry preparation method that the preparation of the slurry of the present invention follows conventional lithium ion battery is made, first by binder
(PVDF etc.) is evenly spread to by mechanical agitation in solvent, then adds active material (nitrating carbon material), fully machine
Tool stirs to form uniform slurry.The proportioning (usage ratio of nitrating carbon material and binder) of each component is wanted without special in slurry
It asks, but nitrating carbon material, as main active substances, dosage accounts for 50% or more of dry material gross mass, dry material gross mass is
The quality of nitrating carbon material+binder+dispersant (when containing dispersant).More preferably, the dosage of nitrating carbon material is more than 80%.Slurry
The solid content of material can adjust the content of solvent so as to adjust slurry solid content, solid content is usually low as needed without particular requirement
In 60%, it is only necessary to ensure that the state of slurry can be easily coated with.Dispersant (such as PVP etc.) side can be added as needed on
Dispersion is helped to obtain uniform slurry, the booster action that binder or dispersant, which play, to be improved slurry form, facilitate coating.Configuration
Binder used in slurry can be the routine such as PVDF, SBR, PTFE, acrylic resin type binder for lithium ion battery
Binder in positive/negative slurry, solvent can be that NMP, water etc. can be used for disperseing binder and the routine of nitrating carbon material is molten
Agent.
Lithium carbon compound cathode piece cooperation conventional cathode piece, diaphragm and the electrolyte of the present invention is (if with solid electrolyte
Can not have to diaphragm) it can be made into lithium secondary battery.Positive active material used by positive plate can be LiFePO4 or cobalt acid lithium
Nickel-cobalt-manganese ternary material or LiMn2O4 or nickel cobalt aluminium ternary material or nickel ion doped or lithium-rich manganese base material or sulphur carbon it is compound just
Pole material.
Below by specific embodiment and comparative example, the present invention is further illustrated.It is arrived used in following the description
Reagent, material and instrument such as not special explanation, are conventional reagent, conventional material and conventional instrument, commercially available
It obtains, involved reagent can also be synthesized by conventional synthesis process and be obtained.
Embodiment 1
First the PVDF dry powder of 0.5kg is added in the nmp solvent of 5kg, is uniformly dispersed, is added by mechanical agitation
The nitrogen-doped carbon nanometer pipe of 4.5kg is mixed to form uniform slurry by mechanical agitation, is coated in copper foil current collector;Drying
The nitrogen-doped carbon nanometer pipe pole piece that coating layer thickness is 1 μm is obtained after solvent;Then by vacuum vapour deposition by lithium metal embedded pole
In the hole of on piece nitrogen-doped carbon nanometer pipe layer, lithium carbon compound cathode piece is obtained.Raw material used in the embedding lithium of the present invention are simple metal
Lithium metal need to be only distributed in the hole of nitrating carbon material by lithium, lithium powder or lithium piece or other shapes of lithium, right
It is not also limited in the amount of embedded lithium metal, is best to fill full lithium metal in nitrating carbon material hole just.
Use winding process, collocation liquid electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are LiFePO4.
Comparative example 1
Comparative example 1 is with 1 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 2
First the PVDF dry powder of 0.25kg is added in the nmp solvent of 10kg, is uniformly dispersed, is added by mechanical agitation
The nitrogen-doped graphene of 4.75kg is mixed to form uniform slurry by mechanical agitation, is coated in copper foil current collector;It dries molten
The nitrogen-doped graphene pole piece that coating layer thickness is 10 μm is obtained after agent;Then lithium metal embedded pole on piece nitrogen is mixed by galvanoplastic
In the hole of miscellaneous graphene layer, lithium carbon compound cathode piece is obtained.
Use lamination process, collocation gel electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are cobalt acid lithium.
Comparative example 2
Comparative example 2 is with 2 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 3
First 1.25kg, the SBR emulsion that solid content is 40% are added in the water of 6kg, are uniformly dispersed by mechanical agitation,
The hard charcoal for adding the N doping of 4.5kg is mixed to form uniform slurry by mechanical agitation, is coated in copper foil current collector;
The N doping hard charcoal pole piece that coating layer thickness is 100 μm is obtained after dry out solvent;Then lithium metal insertion nitrogen is mixed by galvanoplastic
In the hole of miscellaneous hard charcoal pole piece, lithium carbon compound cathode piece is obtained.
Use lamination process, collocation solid electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are nickel-cobalt-manganese ternary material.
Comparative example 3
Comparative example 3 is with 3 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 4
First 0.5kg, the PTFE emulsion that solid content is 60% are added in the water of 8kg, are uniformly dispersed by mechanical agitation,
The soft charcoal for adding the N doping of 4.7kg is mixed to form uniform slurry by mechanical agitation, is coated in copper foil current collector;
The N doping soft charcoal pole piece that coating layer thickness is 60 μm is obtained after dry out solvent;Then by galvanoplastic by lithium metal embedded pole on piece
In the hole of N doping soft charcoal layer, lithium carbon compound cathode piece is obtained.
Use winding process, collocation liquid electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are sulphur carbon composite anode material.
Comparative example 4
Comparative example 4 is with 4 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 5
First 5kg, the acrylic resin binder that solid content is 20% are added in the NMP of 5kg, pass through mechanical agitation point
It dissipates uniformly, adds the activated carbon of the N doping of 4kg, uniform slurry is mixed to form by mechanical agitation, is coated on copper foil collection
On fluid;The nitrogen-dopped activated carbon pole piece that coating layer thickness is 50 μm is obtained after dry out solvent;It then will be golden by vacuum vapour deposition
In the hole for belonging to lithium embedded pole on piece nitrogen-dopped activated carbon layer, lithium carbon compound cathode piece is obtained.
Use winding process, collocation gel electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are manganate cathode material for lithium.
Comparative example 5
Comparative example 5 is with 5 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 6
First the PVDF dry powder of 0.2kg is added in the NMP of 5kg, is uniformly dispersed by mechanical agitation, adds 4.8kg
N doping carbon fiber, uniform slurry is mixed to form by mechanical agitation, is coated in copper foil current collector;After dry out solvent
Obtain the carbon fiber pole piece for the N doping that coating layer thickness is 50 μm;Then by galvanoplastic by lithium metal embedded pole on piece N doping
In the hole of carbon fiber layer, lithium carbon compound cathode piece is obtained.
Use winding process, collocation liquid electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are nickel lithium manganate cathode material.
Comparative example 6
Comparative example 6 is with 6 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 7
First the PVDF dry powder of 1kg is added in the NMP of 20kg, is uniformly dispersed by mechanical agitation, the nitrogen of 4kg is added
The carbon fiber of doping is mixed to form uniform slurry by mechanical agitation, is coated in copper foil current collector;It is obtained after dry out solvent
The nitrogen-doped carbon fiber pole piece that coating layer thickness is 30 μm;Then by vacuum vapour deposition by lithium metal embedded pole on piece nitrogen-doped carbon
In the hole of fibrous layer, lithium carbon compound cathode piece is obtained.
Use lamination process, collocation liquid electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are nickel cobalt aluminium ternary material positive electrode.
Comparative example 7
Comparative example 7 is with 7 different places of embodiment:Negative plate is common lithium anode piece.
Embodiment 8
First the PVDF dry powder of 0.5kg is added in the NMP of 50kg, is uniformly dispersed by mechanical agitation, adds 4.5kg
N doping hard charcoal, uniform slurry is mixed to form by mechanical agitation, is coated in copper foil current collector;After dry out solvent
To the hard charcoal pole piece for the N doping that coating layer thickness is 15 μm;Then by vacuum vapour deposition by lithium metal embedded pole on piece N doping
In the hole of hard charcoal layer, lithium carbon compound cathode piece is obtained.
Use winding process, collocation liquid electrolyte that lithium two is made negative plate obtained and conventional positive plate and diaphragm
Primary cell, the positive active material on positive plate are lithium-rich manganese-based anode material.
Comparative example 8
Comparative example 8 is with 8 different places of embodiment:Negative plate is common lithium anode piece.
Lithium secondary battery made from embodiment 1-8 and comparative example 1-8 is subjected to security test, in 25 DEG C, 0.5C/0.5C
Under cycle performance test, observation cycle after battery lithium dendrite growth situation and the situation of change of negative plate thickness, test result
As shown in table 1.
Table 1
As can be known from the results of Table 1, lithium secondary battery made from the lithium carbon compound cathode piece using the method for the present invention preparation, phase
It being greatly reduced than lithium secondary battery internal resistance made from common metal cathode of lithium, the thickness change for the front and back negative plate that charges is eliminated,
Cycle performance increases substantially, and security performance has also obtained significant increase, significantly inhibits Li dendrite, and reduce Li dendrite
Growth leads to the risk of battery internal short-circuit.
The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.
Various modifications to these embodiments will be apparent to those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, of the invention
It is not intended to be limited to embodiment illustrated herein, and is to fit to consistent with the principles and novel features disclosed in this article
Widest range.