A kind of graphene-supported nanometer LiNiPO anode material of lithium battery and preparation method
Technical field
The invention belongs to the technical fields of anode material of lithium battery, provide a kind of graphene-supported nanometer LiNiPO lithium
Cell positive material and preparation method.
Background technique
Lithium battery is the new generation of green high-energy battery of performance brilliance, it has also become one of emphasis of hi-tech development.Lithium
Battery has the following characteristics that high voltage, high capacity, low consumption, memory-less effect, nuisanceless, small in size, internal resistance is small, self discharge
Less, cycle-index is more.Because of its These characteristics, lithium ion battery has application to mobile phone, laptop, video camera, number
Camera etc. is numerous civilian and military field.
Lithium battery is using two different lithium intercalation compounds that can be reversibly inserted into and deviate from lithium ion as electricity
The anode in pond and the secondary cell system of cathode.When charging, lithium ion is deviate from from the lattice of positive electrode, after electrolyte
It is inserted into the lattice of negative electrode material, so that cathode richness lithium, positive extreme poverty lithium;Lithium ion takes off from the lattice of negative electrode material when electric discharge
Out, it is inserted into after electrolyte in the lattice of positive electrode, so that it is just rich in lithium, the poor lithium of cathode.Lithium ion battery it is main
Constituent material includes electrolyte, isolated material, positive and negative pole material etc..Positive electrode occupies larger proportion, the performance of positive electrode
The performance of lithium ion battery is directly affected, cost also directly determines battery cost height.
In existing positive electrode, LiMPO4(M=Fe, Mn, Co, Ni) is considered as the positive electrode that next battery eliminator uses.
Wherein, LiNiPO (LiNiPO4) there is olivine structural, belong to Pnma space group, Li+And N2+Occupy octahedral voids
Half, P5+The 1/8 of tetrahedral vacancy is occupied, the advantages of this structure is PO4 3-In P-O covalent bond it is very strong, charging when from
To stabilization, it is therefore prevented that the demonstration of oxygen under high voltage ensure that the stabilization and safety of battery;But the disadvantage is that electrical conductance
Poor, lithium ion diffusion is very slow, therefore is the emphasis studied at present for the lift technique of LiNiPO electric conductivity.
Chinese invention patent application number 201410808851.9 discloses a kind of preparation of silicon substrate LiNiPO composite material
Method, first with the mode of ultra-fine sand milling by manganese source compound, doped compound and ammonium phosphate based compound (including di(2-ethylhexyl)phosphate
Hydrogen ammonium, diammonium hydrogen phosphate and triammonium phosphate) molecular formula is prepared by mixing into as SiNi1-xMxPO4Presoma, wherein 0≤x≤0.2,
Any one or a few in Co, Fe, Mg, Ni of M, dispersing agent is organic solvent;Again by SiNi1-xMxPO4Presoma and lithium
Salt compound is transferred in water heating kettle after mixing, is dried to obtain lithium manganese phosphate material after reacting appropriate time at a certain temperature
Material finally prepares silicon substrate LiNiPO composite material using heat treatment carbon-coated mode in situ.But silicon substrate made from the invention
The electric conductivity of LiNiPO composite material is not still ideal enough, and it is poor to be used for high rate performance when lithium battery.
It is multiple that Chinese invention patent application number 201310286222.X discloses a kind of lithium ion battery LiNiPO/carbon
The green synthesis method of condensation material changes the size and interparticle journey of combining closely of particle by carbon coating from the appearance
Degree, reduces Li+Diffusion path, improve the conductivity of lithium ion, metal ion mixing causes the defect of material lattice,
The ionic conductivity of material itself is improved, but the promotion effect of electric conductivity needs to be further strengthened, to adapt to lithium battery more
The development and application of high demand.
In conclusion when the LiNiPO of the prior art is used as anode material of lithium battery, conductive poor, high rate performance
The defect of difference, therefore the LiNiPO positive electrode of a kind of high conductivity and good high rate performance is developed, it has great significance.
Summary of the invention
As it can be seen that when LiNiPO is used as anode material of lithium battery, conductive poor, high rate performance difference defect.For
Such case, the present invention proposes a kind of graphene-supported nanometer LiNiPO anode material of lithium battery and preparation method, obtained
LiNiPO material, ionic conductivity and electronic conductivity are significantly increased, and the stability and charge-discharge performance under high magnification obtain
To improvement.
To achieve the above object, specific technical solution of the present invention is as follows:
A kind of preparation method of graphene-supported nanometer LiNiPO anode material of lithium battery, the graphene-supported nanometer phosphoric acid
Specific step is as follows for the preparation of nickel lithium:
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 2 ~ 3h, nitrogen source, sulphur source, transfer is then added
Into hydrothermal reaction kettle, 200 ~ 220 DEG C of 8 ~ 10h of reaction are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping stone is made
Black alkene nanometer sheet;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then nickel source is added in 2 ~ 3h of ultrasonic disperse, first stir 20 ~ 30min, be then sonicated 3 ~ 5h, so that nickel source is carried on nitrogen sulphur and mix
The surface of miscellaneous graphene nanometer sheet and piece interlayer form suspension;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 10 ~ 20min, Phen then is added simultaneously
20 ~ 30min is stirred, is transferred in hydrothermal reaction kettle, is heated to 150 ~ 160 DEG C of 5 ~ 6h of reaction, it is raw to crystal by Phen
Long control obtains nano bar-shape LiNiPO presoma and is carried on surface and the piece interlayer of graphene nanometer sheet, then non-
Heating makes moist part volatilize to form gel under sealed environment, then uses oven drying, is made that nitrogen sulfur doping is graphene-supported receives
The rodlike LiNiPO presoma xerogel of rice;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, first with 8 ~ 10 DEG C/min liter
Temperature is warming up to 600 ~ 650 DEG C of 2 ~ 4h of calcining, cooled to room temperature, system to 300 ~ 350 DEG C of 1 ~ 2h of pre-burning, then with 4 ~ 6 DEG C/min
Obtain the graphene-supported nanometer LiNiPO positive electrode of nitrogen sulfur doping.
LiNiPO is loaded by using graphene nanometer sheet, since graphene has excellent electric conductivity,
The defect of LiNiPO material conductivity difference can be significantly improved.Also, using graphene nanometer sheet as skeleton, LiNiPO is consolidated
Surface and piece interlayer due to nanometer sheet can prevent from leading to falling off for LiNiPO because electrolyte immerses in charge and discharge process, from
And improve stability and charge-discharge performance of the LiNiPO under high magnification.
Since nitrogen-atoms, sulphur atom are capable of providing additional electronics and electron carrier, it is total that nitrogen sulphur is carried out to graphene
Doping, can further enhance the conductive capability of graphene, significantly improve the electronic conductivity of LiNiPO material.Meanwhile nitrogen
Atom, sulphur atom can partially enter in the structure of LiNiPO, and inducement structure generates defect, to reduce the work of lithium ion diffusion
Change energy, the ionic conductivity of LiNiPO material is made to increase.As a preferred solution of the present invention, the nitrogen source be ammonium hydroxide,
One of ethylenediamine, urea, the sulphur source are one of elemental sulfur, hydrogen sulfide, thiocarbamide.
In order to not only reach the good doping vario-property effect of graphene, but also the load capacity of graphene is not influenced, it need to be to nitrogen, sulphur
Doping limited, as a preferred solution of the present invention, in the nitrogen source nitrogenous weight be graphene oxide weight
4 ~ 8%, the weight of institute's sulfur-bearing is the 3 ~ 5% of graphene oxide weight in the sulphur source.
Preferably, the weight of the in the mixed solvent of the n,N-Dimethylformamide and water, n,N-Dimethylformamide and water
Amount is than being 1:2 ~ 2:1.
Nickel source is first carried on the skeleton of nitrogen sulfur doping graphene nanometer sheet by the present invention, then carries out water with lithium source, phosphorus source
Thermal response, the LiNiPO to generate after being allowed to is formed in graphene nano on piece securely to be loaded and is evenly distributed, originally nickel source
Secured and uniform load in nanometer sheet is extremely important.As a preferred solution of the present invention, the nickel source using nickel hydroxide,
One of hydroxy nickel oxide.In general, the nickel source that can be used for synthesizing LiNiPO is more, such as nickel sulfate, nickel hydroxide, carbonic acid
Nickel, nickel oxalate, nickel phosphate, hydroxy nickel oxide etc., but due to containing OH in the molecular structure of nickel hydroxide and hydroxy nickel oxide-,
O-H ... N key or O-H ... S key can be formed with N atom, the S atom adulterated in graphene, thus be more advantageous to form steady load,
It is therefore preferable that nickel source is nickel hydroxide and hydroxy nickel oxide.
As a preference of the present invention, the lithium source is one of lithium carbonate, lithium oxalate, lithium phosphate, phosphorus source is phosphorus
One of sour ammonium, ammonium dihydrogen phosphate.
As a preference of the present invention, in the nickel source, lithium source, phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:1.5 ~ 2:1.
On the one hand the excess of lithium is the volatilization due to lithium at high temperature, on the other hand, it has been found that when the stoichiometry mistake of lithium
When amount is not less than 0.5 times, it is easier to obtain the LiNiPO material of small size.It is therefore preferable that the molal quantity of lithium is excessive in scheme
0.5 ~ 1 times.
During hydro-thermal reaction synthesizes LiNiPO, Phen can control brilliant in reaction process as complexing agent
The growth of body has an impact crystalline size and crystal form.When crystal is grown using graphene nanometer sheet skeleton as carrier,
Tend to form flat crystal, and Phen tends to promote the spherical growth of crystal, under the two collective effect, crystal turns
Become in thin rodlike growth.Phen can also prevent the intercrystalline fusion of LiNiPO, ultimately form nano bar-shape nickel phosphate
Lithium material.Preferably, the additional amount of the Phen is the 3 ~ 5% of suspension total weight.
Preferably, the protective gas is nitrogen or helium.
The present invention also provides a kind of graphene-supported nanometer LiNiPO lithiums that a kind of above-mentioned preparation method is prepared
Cell positive material.The graphene-supported nanometer LiNiPO is received by first using hydro-thermal method to prepare nitrogen sulfur doping graphene
Nickel source, is then carried on surface and the piece interlayer of graphene nanometer sheet, adds lithium source, phosphorus source, and in Phen by rice piece
Control under carry out hydro-thermal reaction generate graphene-supported nano bar-shape LiNiPO presoma, be then dried to obtain presoma
Xerogel is sintered and is made after pulverizing.The electronic conductivity of positive electrode obtained is 1.8 ~ 2.2 × 10-1S/cm,
Ionic conductivity is 1.4 ~ 1.8 × 10-1S/cm, the first charge-discharge specific capacity for assembling manufactured button cell are in 0.1C multiplying power
150 ~ 157mAh/g, 50 Zhou Houwei capacity retention ratio of charge and discharge cycles are 95 ~ 97%;It is 140 ~ 150mAh/g, charge and discharge under 1C multiplying power
Electricity 50 Zhou Houwei capacity retention ratios of circulation are 92 ~ 94%;It is 118 ~ 125mAh/g under 5C multiplying power, 50 Zhou Houwei of charge and discharge cycles holds
Measuring conservation rate is 85 ~ 88%;It is 96 ~ 100mAh/g under 10C multiplying power, 50 Zhou Houwei capacity retention ratio of charge and discharge cycles is 78 ~ 80%.
It is and existing the present invention provides a kind of graphene-supported nanometer LiNiPO anode material of lithium battery and preparation method
Technology is compared, and the feature and excellent effect protruded is:
1. preparation method of the invention, the load by graphene nanometer sheet to LiNiPO, improve the electronics of LiNiPO
Stability and charge-discharge performance under conductivity, high magnification, further, by carrying out nitrogen sulphur codope to graphene, to electricity
Electron conductivity and ionic conductivity are improved.
2. preparation method of the invention will first contain OH-Nickel source steady load in the graphene nano on piece of nitrogen sulfur doping,
Be conducive to securely loading and be uniformly distributed for the LiNiPO generated, improve stability.
3. preparation method of the invention controls crystal growth using Phen as complexing agent in hydrothermal reaction process, make
LiNiPO obtained is nano bar-shape, shortens lithium ion mobility path, ionic conductivity can be made to significantly improve.
Specific embodiment
In the following, the present invention will be further described in detail by way of specific embodiments, but this should not be interpreted as to the present invention
Range be only limitted to example below.Without departing from the idea of the above method of the present invention, according to ordinary skill
The various replacements or change that knowledge and customary means are made, should be included in the scope of the present invention.
Embodiment 1
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 2.5h, nitrogen source, sulphur source, transfer is then added
Into hydrothermal reaction kettle, 210 DEG C of reaction 8.5h are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping graphene is made
Nanometer sheet;Nitrogen source is ammonium hydroxide;Nitrogenous weight is the 7% of graphene oxide weight in nitrogen source;Sulphur source is elemental sulfur;In sulphur source
The weight of institute's sulfur-bearing is the 3.5% of graphene oxide weight;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then ultrasonic disperse 2.5h is added nickel source, first stirs 24min, is then sonicated 3.5h, nickel source is made to be carried on nitrogen sulfur doping
The surface of graphene nanometer sheet and piece interlayer form suspension;Nickel source is nickel hydroxide;N,N-dimethylformamide and water it is mixed
In bonding solvent, the weight ratio of n,N-Dimethylformamide and water is 1:1;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 16min, Phen is then added and stirs
24min is transferred in hydrothermal reaction kettle, is heated to 156 DEG C of reaction 5.5h, and then heating makes moist part in non-hermetic environments
Volatilization forms gel, then uses oven drying, and it is solidifying that the graphene-supported nano bar-shape LiNiPO forerunner's soma of nitrogen sulfur doping is made
Glue;Lithium source is lithium carbonate;Phosphorus source is ammonium phosphate;Nickel source, lithium source, in phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:1.7:1;It is adjacent
The additional amount of ferrosin is the 4.5% of suspension total weight;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, is first warming up to 9 DEG C/min
330 DEG C of pre-burning 1.5h, then 630 DEG C of calcining 3h are warming up to 5 DEG C/min, nitrogen sulfur doping graphene is made in cooled to room temperature
Load nanometer LiNiPO positive electrode;Protective gas is nitrogen.
Embodiment 2
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 2h, nitrogen source, sulphur source is then added, is transferred to
In hydrothermal reaction kettle, 205 DEG C of reaction 9.5h are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping graphene is made and receives
Rice piece;Nitrogen source is ethylenediamine;Nitrogenous weight is the 5% of graphene oxide weight in nitrogen source;Sulphur source is hydrogen sulfide;In sulphur source
The weight of institute's sulfur-bearing is the 3.5% of graphene oxide weight;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then ultrasonic disperse 2h is added nickel source, first stirs 22min, is then sonicated 4.5h, nickel source is made to be carried on nitrogen sulfur doping stone
The surface of black alkene nanometer sheet and piece interlayer form suspension;Nickel source is hydroxy nickel oxide;N,N-dimethylformamide and water it is mixed
In bonding solvent, the weight ratio of n,N-Dimethylformamide and water is 1:2;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 12min, Phen is then added and stirs
23min is transferred in hydrothermal reaction kettle, is heated to 152 DEG C of reaction 6h, and then heating waves moist part in non-hermetic environments
Hair forms gel, then uses oven drying, and the graphene-supported nano bar-shape LiNiPO presoma xerogel of nitrogen sulfur doping is made;
Lithium source is lithium oxalate;Phosphorus source is ammonium dihydrogen phosphate;Nickel source, lithium source, in phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:1.6:1;
The additional amount of Phen is the 3.5% of suspension total weight;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, is first warming up to 8 DEG C/min
340 DEG C of pre-burning 1h, then 610 DEG C of calcining 3.5h are warming up to 4 DEG C/min, nitrogen sulfur doping graphene is made in cooled to room temperature
Load nanometer LiNiPO positive electrode;Protective gas is helium.
Embodiment 3
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 3h, nitrogen source, sulphur source is then added, is transferred to
In hydrothermal reaction kettle, 215 DEG C of reaction 8.5h are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping graphene is made and receives
Rice piece;Nitrogen source is urea;Nitrogenous weight is the 7% of graphene oxide weight in nitrogen source;Sulphur source is thiocarbamide;It is contained in sulphur source
The weight of sulphur is the 4.5% of graphene oxide weight;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then ultrasonic disperse 3h is added nickel source, first stirs 28min, is then sonicated 4.5h, nickel source is made to be carried on nitrogen sulfur doping stone
The surface of black alkene nanometer sheet and piece interlayer form suspension;Nickel source is nickel hydroxide;The mixing of N,N-dimethylformamide and water
In solvent, the weight ratio of n,N-Dimethylformamide and water is 2:1;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 18min, Phen is then added and stirs
28min is transferred in hydrothermal reaction kettle, is heated to 158 DEG C of reaction 5h, and then heating waves moist part in non-hermetic environments
Hair forms gel, then uses oven drying, and the graphene-supported nano bar-shape LiNiPO presoma xerogel of nitrogen sulfur doping is made;
Lithium source is lithium phosphate;Phosphorus source is ammonium phosphate;Nickel source, lithium source, in phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:1.9:1;Neighbour two
The additional amount of nitrogen phenanthrene is the 4.5% of suspension total weight;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, is first warming up to 9 DEG C/min
340 DEG C of pre-burning 2h, then 640 DEG C of calcining 2.5h are warming up to 6 DEG C/min, nitrogen sulfur doping graphene is made in cooled to room temperature
Load nanometer LiNiPO positive electrode;Protective gas is nitrogen.
Embodiment 4
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 2h, nitrogen source, sulphur source is then added, is transferred to
In hydrothermal reaction kettle, 200 DEG C of reaction 10h are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping graphene nano is made
Piece;Nitrogen source is ammonium hydroxide;Nitrogenous weight is the 4% of graphene oxide weight in nitrogen source;Sulphur source is elemental sulfur;It is contained in sulphur source
The weight of sulphur is the 3% of graphene oxide weight;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then ultrasonic disperse 2h is added nickel source, first stirs 20min, is then sonicated 3h, nickel source is made to be carried on nitrogen sulfur doping graphite
The surface of alkene nanometer sheet and piece interlayer form suspension;Nickel source is hydroxy nickel oxide;The mixing of N,N-dimethylformamide and water
In solvent, the weight ratio of n,N-Dimethylformamide and water is 1:2;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 10min, Phen is then added and stirs
20min is transferred in hydrothermal reaction kettle, is heated to 150 DEG C of reaction 6h, and then heating waves moist part in non-hermetic environments
Hair forms gel, then uses oven drying, and the graphene-supported nano bar-shape LiNiPO presoma xerogel of nitrogen sulfur doping is made;
Lithium source is lithium carbonate;Phosphorus source is ammonium dihydrogen phosphate;Nickel source, lithium source, in phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:1.5:1;
The additional amount of Phen is the 3% of suspension total weight;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, is first warming up to 8 DEG C/min
300 DEG C of pre-burning 2h, then 600 DEG C of calcining 4h are warming up to 4 DEG C/min, it is negative that nitrogen sulfur doping graphene is made in cooled to room temperature
Carry nanometer LiNiPO positive electrode;Protective gas is helium.
Embodiment 5
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 3h, nitrogen source, sulphur source is then added, is transferred to
In hydrothermal reaction kettle, 220 DEG C of reaction 8h are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping graphene nano is made
Piece;Nitrogen source is ethylenediamine;Nitrogenous weight is the 8% of graphene oxide weight in nitrogen source;Sulphur source is hydrogen sulfide;Institute in sulphur source
The weight of sulfur-bearing is the 5% of graphene oxide weight;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then ultrasonic disperse 3h is added nickel source, first stirs 30min, is then sonicated 5h, nickel source is made to be carried on nitrogen sulfur doping graphite
The surface of alkene nanometer sheet and piece interlayer form suspension;Nickel source is nickel hydroxide;The mixing of N,N-dimethylformamide and water is molten
In agent, the weight ratio of n,N-Dimethylformamide and water is 2:1;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 20min, Phen is then added and stirs
30min is transferred in hydrothermal reaction kettle, is heated to 160 DEG C of reaction 5h, and then heating waves moist part in non-hermetic environments
Hair forms gel, then uses oven drying, and the graphene-supported nano bar-shape LiNiPO presoma xerogel of nitrogen sulfur doping is made;
Lithium source is lithium phosphate;Phosphorus source is ammonium phosphate;Nickel source, lithium source, in phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:2:1;Adjacent phenodiazine
Luxuriant and rich with fragrance additional amount is the 5% of suspension total weight;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, first with 10 DEG C/min heating
650 DEG C of calcining 2h are warming up to 350 DEG C of pre-burning 1h, then with 6 DEG C/min, nitrogen sulfur doping graphene is made in cooled to room temperature
Load nanometer LiNiPO positive electrode;Protective gas is nitrogen.
Embodiment 6
(1) it disperses stannic oxide/graphene nano piece in deionized water, is ultrasonically treated 2.5h, nitrogen source, sulphur source, transfer is then added
Into hydrothermal reaction kettle, 210 DEG C of reaction 9h are heated to, is then filtered, washed, is freeze-dried, nitrogen sulfur doping graphene is made and receives
Rice piece;Nitrogen source is urea;Nitrogenous weight is the 6% of graphene oxide weight in nitrogen source;Sulphur source is thiocarbamide;It is contained in sulphur source
The weight of sulphur is the 4% of graphene oxide weight;
(2) nitrogen sulfur doping graphene nanometer sheet made from step (1) is added to the mixed solvent of N,N-dimethylformamide and water
In, then ultrasonic disperse 2.5h is added nickel source, first stirs 25min, is then sonicated 4h, nickel source is made to be carried on nitrogen sulfur doping stone
The surface of black alkene nanometer sheet and piece interlayer form suspension;Nickel source is hydroxy nickel oxide;N,N-dimethylformamide and water it is mixed
In bonding solvent, the weight ratio of n,N-Dimethylformamide and water is 1:1;
(3) lithium source, phosphorus source are added into suspension made from step (2) and stirs 15min, Phen is then added and stirs
25min is transferred in hydrothermal reaction kettle, is heated to 155 DEG C of reaction 5.5h, and then heating makes moist part in non-hermetic environments
Volatilization forms gel, then uses oven drying, and it is solidifying that the graphene-supported nano bar-shape LiNiPO forerunner's soma of nitrogen sulfur doping is made
Glue;Lithium source is lithium oxalate;Phosphorus source is ammonium dihydrogen phosphate;Nickel source, lithium source, in phosphorus source nickeliferous, lithium, phosphorus molar ratio be 1:1.8:
1;The additional amount of Phen is the 4% of suspension total weight;
(4) presoma xerogel made from step (3) is pulverized, in the presence of protective gas, is first warming up to 9 DEG C/min
320 DEG C of pre-burning 1.5h, then 625 DEG C of calcining 3h are warming up to 5 DEG C/min, nitrogen sulfur doping graphene is made in cooled to room temperature
Load nanometer LiNiPO positive electrode;Protective gas is helium.
Comparative example 1
In preparation process, nitrogen sulphur codope is not carried out to graphene, other preparation conditions and embodiment 6 are consistent.
Comparative example 2
In preparation process, it is not added with Phen, other preparation conditions and embodiment 6 are consistent.
Comparative example 3
It in preparation process, is not loaded using graphene, other preparation conditions and embodiment 6 are consistent.
Performance test:
2400 microporous polypropylene membrane of LiPF is diaphragm, and positive plate is made in positive electrode produced by the present invention by 1mol/L, with
Celgard6Mixed organic solvents (EC:DMC=1:1, volume ratio) be electrolyte, be that argon is being full of to pole piece with metal lithium sheet
It is assembled into the button cell of model CR2025 in the glove box of gas, is once tested:
(1) electronic conductivity, ionic conductivity: after carrying out electrochemistry circulation 1 week using Land CT2001A battery test system,
With the electrochemical impedance of Zahner IM6ex type electrochemical workstation measurement material, measurement frequency range is 10kHz ~ 10mHz,
Perturbation voltage is 5mV, tests and calculate the electronic conductivity and ionic conductivity of positive electrode;
(2) charge and discharge cycles test specific capacity: carrying out charge and discharge cycles test, charging/discharging voltage using battery performance testing system
Range is 2 ~ 4V, test respectively multiplying power be respectively under 0.1C, 1C, 5C and 10C multiplying power for the first time, 50 weeks charge and discharge specific volumes of circulation
Amount.
The data obtained is as shown in table 1.
Table 1: