Summary of the invention
In order to solve above-mentioned the deficiencies in the prior art part, primary and foremost purpose of the present invention is to provide a kind of lithium cell cathode material of pitch liquid phase coating modified artificial graphite, the artificial plumbago negative pole material of this modification first efficiency up to 93% and first specific capacity reach 355mAh/g, its first charge-discharge efficiency is high, specific capacity is high, has solved Delanium material in the actual problem that irreversible capacity loss is large, specific capacity is lower existing while preparing the application of cathode of lithium battery.
Another object of the present invention is to provide the lithium cell cathode material of above-mentioned a kind of pitch liquid phase coating modified artificial graphite.
A further object of the present invention is to provide the lithium cell cathode material application of above-mentioned a kind of pitch liquid phase coating modified artificial graphite.
For achieving the above object, the present invention adopts following technical scheme:
A preparation method for the lithium cell cathode material of pitch liquid phase coating modified artificial graphite, concrete steps are as follows:
(1) petroleum coke is carried out to mechanical crushing, then powder is carried out to mechanical ball milling and obtain fine powder, and carry out fine powder classification processing;
(2) fine powder after classification is mixed with 3 ~ 8 quality % pitch powders, then the powder mixing is put in middle temperature reactor and reacted, last discharging;
(3) discharging powder is carried out to shaping classification processing again through shaping grader;
(4) product of above-mentioned gained is carried out to high temperature graphitization processing, and then process through classification, can obtain Delanium materials A, the D50 of described Delanium materials A is 10 μ m;
(5) the prepared A of step 1 is added in the beaker that a certain amount of absolute ethyl alcohol is housed, and dispersed with stirring 10min ~ 30min, mixture B obtained;
(6) 5% ~ 15% the pitch that takes Delanium A quality is dissolved in a certain amount of oxolane, and high-speed stirred 0.5 ~ 1h, dissolves pitch more abundant, crosses 200 objects sieves, removes residue, obtains mixed liquor C;
(7) mixed liquor C is slowly poured in the beaker that mixture B is housed, then add absolute ethyl alcohol to regulate solids content to 10 ~ 30% of slurry, continue to stir 0.5 ~ 1h, then mixed liquor C is carried out to the dry powder process of closed cycle spraying, obtain presoma D;
(8) presoma D step (7) being obtained is warming up to 700 ~ 1100 ℃ in inert gas environment, and constant temperature keeps 1 ~ 5h, obtains the artificial plumbago negative pole material of described pitch liquid phase coating modification.
The present invention uses the spray-dired mode of closed cycle to prepare powder, pitch is dispersed on Delanium surface, after high-temperature heat treatment, forms the unbodied charcoal of one deck after asphalt carbonization, tightly be wrapped in Delanium, form the composite material of a kind of " core-shell " structure.The specific area of material has not only been lowered in the existence of coating layer, stoped entering of organic solvent, reach the object that obtains even, fine and close SEI film, simultaneously, surface Carbon Materials energy anchor stone ink sheet, prevent coming off of graphite top layer, make efficiency first, specific capacity and the cyclical stability of material obtain certain raising.Therefore, the first charge-discharge efficiency of the prepared modified artificial graphite of the present invention is high, specific capacity is high, good cycle.
Preferably, in the condition of reaction described in step (2), reactor temperature is 500 ~ 650 ℃, and in still, mixing speed is 20 ~ 50r/min, and the reaction time is 6-10h; High temperature graphitization described in step (4) is processed, 2400 ℃ ~ 3000 ℃ of graphitization temperatures, processing time 36 ~ 72h.
Preferably, in step (5), (6) and (7), mixing speed is 400 ~ 2000r/min; Wherein, the mixing speed of step (5) is preferably 400 ~ 800r/min, and the mass ratio of graphite material A and absolute ethyl alcohol is 1:4 ~ 10; The mixing speed of step (6) is preferably 800 ~ 1200r/min, and the mass ratio of pitch and oxolane is 1:4 ~ 10; The mixing speed of step (6) is preferably 1800 ~ 2000r/min; Dry powder process described in step (7) is undertaken by closed cycle spray dryer, described closed cycle spray dryer is centrifugal atomizer, its rotating speed is 15000 ~ 40000r/min, and out temperature is respectively 100 ~ 150 ℃ and 80 ~ 100 ℃, and charging rate is 20 ~ 30mL/min; Inert gas described in step (8) is that purity is the argon gas that 99.999% nitrogen or purity are 99.999%, and programming rate is 2~5 ℃/min.
In the preparation process of lithium cell cathode material, the conditions such as the kind of applied dispersant and organic carbon source, sintering temperature and spray-dired technique all can produce a very large impact the structure of prepared lithium cell cathode material, size and pattern, and the structure of product, size and pattern can produce impact greatly to the performance of lithium cell cathode material, and then have influence on first charge-discharge, specific capacity and the cycle performance of lithium cell cathode material.Therefore, in the present invention, inventor by the process conditions such as the kind of dispersant, organic carbon source, spray-dired technique, sintering temperature preferably, obtained that a kind of first charge-discharge efficiency is high, specific capacity is high, the Delanium material negative material of the pitch liquid phase coating modification of good cycle.
By detection, find, artificial plumbago negative pole material after the pitch liquid phase coating modification that preparation method of the present invention obtains first efficiency reaches 93%, more than reversible specific capacity reaches 355mAh/g first, higher than the Delanium (efficiency 90% first, first reversible specific capacity 345mAh/g) before unmodified.
The application of the lithium battery cathode plate of the Delanium of above-mentioned pitch liquid phase coating modification; The preparation method of described lithium battery cathode plate comprises the steps:
(1) by lithium cell cathode material, binding agent and the conductive agent of the Delanium of pitch liquid phase coating modification according to (88 ~ 93): (5 ~ 10): 2 weight ratio is evenly mixed, and obtains slurry;
(2) slurry obtaining in step (1) is coated on Copper Foil, through vacuumize 5 ~ 24h, then roll-in, obtains described lithium battery cathode plate.
Preferably, the weight ratio of lithium cell cathode material, binding agent and the conductive agent of the Delanium of described pitch liquid phase coating modification is 89:9:2.
Preferably, described binding agent is binding agent LA133 or polyvinylidene fluoride; Described conductive agent is conductive carbon black Super-P, acetylene black, nano-sized carbon or conduction liquid.
Described conduction liquid is conventional commercial commercial conduction liquid; Described binding agent LA133 is a water system binding agent that Chengdu Yin Dile company produces.
Preferably, the coating thickness described in step (2) is 100 ~ 180 microns; Described roll-in thickness is 75 ~ 150 microns; Described vacuumize temperature is 50 ~ 100 ℃.
The present invention compared with prior art, advantage specific as follows and beneficial effect:
The lithium cell cathode material of the Delanium of the pitch liquid phase coating modification that preparation method disclosed in this invention obtains, is the composite material of a kind of " core-shell " structure, makes efficiency first, specific capacity and the cyclical stability of material obtain certain raising.
Secondly, the technique for applying of the lithium cell cathode material of the Delanium of pitch liquid phase coating disclosed by the invention modification is simple, with low cost, production efficiency is high and be suitable for industrial-scale production.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited to this.Unless otherwise noted, all raw materials in the present invention and reagent are conventional commercial raw material, reagent.
embodiment 1
(1) preparation of the lithium cell cathode material of the Delanium of pitch liquid phase coating modification:
(1) petroleum coke is carried out to mechanical crushing, then powder is carried out to mechanical ball milling and obtain fine powder, and carry out fine powder classification processing;
(2) fine powder after classification is mixed with appropriate (5%) pitch powder, then (reactor temperature is 500 ℃ the powder mixing to be put in middle temperature reactor to reaction, in still, mixing speed is 40r/min, and the reaction time is 8h), last discharging.
(3) discharging powder is carried out to shaping classification processing again through shaping grader;
(4) product of above-mentioned gained is carried out to high temperature graphitization processing (2500 ℃ of insulation 36h), and then process through classification, can obtain Delanium materials A (D
50=10um).
(5) the prepared A of step 1 is added in the beaker that a certain amount of absolute ethyl alcohol is housed, and stir (400 r/min) and disperse 20min, obtain mixture B;
(6) 10% the pitch that takes Delanium A quality is dissolved in a certain amount of oxolane, and (1000 r/min) stirs 40min at a high speed, pitch dissolved more abundant, crosses 200 objects sieves, removes residue, obtains mixed liquor C.
(7) mixed liquor C is slowly poured in the beaker that mixture B is housed, then add absolute ethyl alcohol to regulate the solids content to 30% of slurry, continue (2000 r/min) fast and stir 50min, again mixed liquor C is carried out under certain conditions to the dry powder process of closed cycle spraying, obtain presoma D, wherein certain condition refers to: centrifugal atomizer rotating speed 30000r/min, and out temperature is respectively 150 ℃ and 100 ℃, charging rate 25mL/min;
(8) presoma D step (3) being obtained is placed in reactor, and toward to pass into purity in reactor be 99.999% nitrogen and be warming up to 900 ℃ with the speed of 3 ℃/min, constant temperature keeps 4h, obtains the artificial plumbago negative pole material of described pitch liquid phase coating modification.
(2) product finally obtaining is carried out to SEM pattern and detect mutually with XRD thing, as shown in Figure 1, XRD thing phase testing result as shown in Figure 2 for SEM pattern testing result.As can be seen from Figure 1, from Fig. 1, can see, graphite granule surface part has covered dense RESEARCH OF PYROCARBON, has reduced specific area, thereby has reduced the area of electrolyte and surface reaction, is conducive to improve efficiency first.And can see from the XRD thing phase testing result of Fig. 2, the standard card JCPDSno.041-1487 of this collection of illustrative plates and cliftonite matches, and chemical reaction does not occur and produce new thing phase.
(3) preparation of lithium battery cathode plate:
The lithium cell cathode material of the pitch liquid phase coating modified artificial graphite that the step of 0.89g () is made is 15% with the binding agent LA133(binding agent solids content of 0.6g), the conductive carbon black Super-P of 0.02g evenly mixes, furnishing slurry, be coated on Copper Foil, coating thickness is 100 microns, and is prepared into lithium battery cathode plate 1 through dry 10 hours of 100 ℃, vacuum, roll-in (thickness is 85 microns).
embodiment 2
(1) preparation of the lithium cell cathode material of the Delanium of pitch liquid phase coating modification:
(1) petroleum coke is carried out to mechanical crushing, then powder is carried out to mechanical ball milling and obtain fine powder, and carry out fine powder classification processing;
(2) fine powder after classification is mixed with appropriate (5%) pitch powder, then (reactor temperature is 500 ℃ the powder mixing to be put in middle temperature reactor to reaction, in still, mixing speed is 40r/min, and the reaction time is 8h), last discharging.
(3) discharging powder is carried out to shaping classification processing again through shaping grader;
(4) product of above-mentioned gained is carried out to high temperature graphitization processing (2500 ℃ of insulation 36h), and then process through classification, can obtain Delanium materials A (D
50=10um).
(5) the prepared A of step 1 is added in the beaker that a certain amount of absolute ethyl alcohol is housed, and stir (800 r/min) and disperse 10min, obtain mixture B;
(6) 10% the pitch that takes Delanium A quality is dissolved in a certain amount of oxolane, and (1000 r/min) stirs 1h at a high speed, pitch dissolved more abundant, crosses 200 objects sieves, removes residue, obtains mixed liquor C.
(7) mixed liquor C is slowly poured in the beaker that mixture B is housed, then add absolute ethyl alcohol to regulate the solids content to 10% of slurry, continue (1200 r/min) fast and stir 1h, again mixed liquor C is carried out under certain conditions to the dry powder process of closed cycle spraying, obtain presoma D, wherein certain condition refers to: centrifugal atomizer rotating speed 15000r/min, and out temperature is respectively 100 ℃ and 80 ℃, charging rate 30mL/min;
(8) presoma D step (3) being obtained is placed in reactor, toward to pass into purity in reactor be 99.999% nitrogen and be warming up to 1100 ℃ with the speed of 5 ℃/min, constant temperature keeps 1h, obtains the artificial plumbago negative pole material of described pitch liquid phase coating modification.
(2) preparation of lithium battery cathode plate:
The lithium cell cathode material of the pitch liquid phase coating modified artificial graphite that the step of 0.89g () is made is 15% with the binding agent LA133(binding agent solids content of 0.6g), the conductive carbon black Super-P of 0.02g evenly mixes, furnishing slurry, be coated on Copper Foil, coating thickness is 100 microns, and is prepared into lithium battery cathode plate 2 through dry 10 hours of 100 ℃, vacuum, roll-in (thickness is 85 microns).
embodiment 3
(1) preparation of the lithium cell cathode material of the Delanium of pitch liquid phase coating modification:
(1) petroleum coke is carried out to mechanical crushing, then powder is carried out to mechanical ball milling and obtain fine powder, and carry out fine powder classification processing;
(2) fine powder after classification is mixed with appropriate (5%) pitch powder, then (reactor temperature is 500 ℃ the powder mixing to be put in middle temperature reactor to reaction, in still, mixing speed is 40r/min, and the reaction time is 8h), last discharging.
(3) discharging powder is carried out to shaping classification processing again through shaping grader;
(4) product of above-mentioned gained is carried out to high temperature graphitization processing (2500 ℃ of insulation 36h), and then process through classification, can obtain Delanium materials A (D
50=10um).
(5) the prepared A of step 1 is added in the beaker that a certain amount of absolute ethyl alcohol is housed, and stir (500 r/min) and disperse 30min, obtain mixture B;
(6) 10% the pitch that takes Delanium A quality is dissolved in a certain amount of oxolane, and (800 r/min) stirs 0.5h at a high speed, pitch dissolved more abundant, crosses 200 objects sieves, removes residue, obtains mixed liquor C.
(7) mixed liquor C is slowly poured in the beaker that mixture B is housed, then add absolute ethyl alcohol to regulate the solids content to 20% of slurry, continue (2000 r/min) fast and stir 1h, again mixed liquor C is carried out under certain conditions to the dry powder process of closed cycle spraying, obtain presoma D, wherein certain condition refers to: centrifugal atomizer rotating speed 20000r/min, and out temperature is respectively 120 ℃ and 85 ℃, charging rate 20mL/min;
(8) presoma D step (3) being obtained is placed in reactor, and toward to pass into purity in reactor be 99.999% nitrogen and be warming up to 700 ℃ with the speed of 2 ℃/min, constant temperature keeps 5h, obtains the artificial plumbago negative pole material of described pitch liquid phase coating modification.
(2) preparation of lithium battery cathode plate:
The lithium cell cathode material of the pitch liquid phase coating modified artificial graphite that the step of 0.89g () is made is 15% with the binding agent LA133(binding agent solids content of 0.6g), the conductive carbon black Super-P of 0.02g evenly mixes, furnishing slurry, be coated on Copper Foil, coating thickness is 100 microns, and is prepared into lithium battery cathode plate 3 through dry 10 hours of 100 ℃, vacuum, roll-in (thickness is 85 microns).
embodiment 4(comparative example)
(1) preparation of the lithium cell cathode material of unmodified Delanium:
(1) petroleum coke is carried out to mechanical crushing, then powder is carried out to mechanical ball milling and obtain fine powder, and carry out fine powder classification processing;
(2) fine powder after classification is mixed with appropriate (5%) pitch powder, then (reactor temperature is 500 ℃ the powder mixing to be put in middle temperature reactor to reaction, in still, mixing speed is 40r/min, and the reaction time is 8h), last discharging.
(3) discharging powder is carried out to shaping classification processing again through shaping grader;
(4) product of above-mentioned gained is carried out to high temperature graphitization processing (2500 ℃ of insulation 36h), and then process through classification, can obtain Delanium materials A (D
50=10um).
(2) preparation of lithium battery cathode plate:
The lithium cell cathode material of the unmodified Delanium that the step of 0.89g () is made is 15% with the binding agent LA133(binding agent solids content of 0.6g), the conductive carbon black Super-P of 0.02g evenly mixes, furnishing slurry, be coated on Copper Foil, coating thickness is 100 microns, and is prepared into lithium battery cathode plate 4 through dry 10 hours of 100 ℃, vacuum, roll-in (thickness is 85 microns).
In above-described embodiment 1 ~ 4 in the preparation of lithium battery cathode plate, binding agent is all chosen as binding agent LA132 and conductive agent is Super-P, the weight ratio of each raw material is identical, and all identical to lithium battery cathode plate coating thickness and roll-in thickness, only for the effect to above-described embodiment better compares, rather than to binding agent and conductive agent kind, raw material weight than and the restriction of lithium battery cathode plate thickness.
embodiment 5-9
Except following table mark parameter, other parameters and preparation method are with embodiment 3
effect embodiment
By the resulting lithium battery cathode plate 1~9 of embodiment 1~9 respectively with the three component mixed solvent EC:DMC:EMC=1:1:1(volume ratio v/v/v of 1mol/L LiPF6), solution is electrolyte, microporous polypropylene membrane is barrier film, and lithium sheet is that positive plate is assembled into simulated battery 1~9.
Simulated battery is carried out to 1~9 and carry out performance test, adopt (Wuhan Jin Nuo Electronics Co., Ltd.) LAND battery test system charging and discharging capacity cycle performance of test simulation battery 1~9 respectively.Wherein, with the electric current of 100mA/g, carrying out the experiment of constant current charge-discharge specific capacity loop test, charging/discharging voltage is limited in 0.01~2. 5V.Test result is as follows:
Above-described embodiment is preferably execution mode of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under Spirit Essence of the present invention and principle, substitutes, combination, simplify; all should be equivalent substitute mode, within being included in protection scope of the present invention.