The preparation method of lithium rechargeable battery Mg2Si/SiOx/C composite negative pole material membrane electrode
Technical field
The present invention relates to a kind of lithium rechargeable battery Mg
2si/SiO
xthe preparation method of/C composite negative pole material membrane electrode.
Background technology
The develop rapidly of lithium ion battery depends on the exploitation of novel energy material and polytechnic progress.Wherein new electrode materials especially negative material exploration and research just seem particularly important.Current business-like negative material adopts the embedding lithium material with carbon elements such as graphite as negative pole mostly, although for lithium metal, in cycle performance and security performance, had significant improvement, but when still there is first charge-discharge, carbon surface generates passivating film and the problem that causes irreversible capacity loss larger.In addition, the current potential of carbon electrode is close with lithium current potential, still may form Li dendrite and cause battery short circuit when battery overcharge, causes safety problem.Therefore, find from resource, environmental protection and secure context the study hotspot that the desirable negative material of lithium ion battery is still quite a while World chemical power supply circle from now on.
In order to meet the demand of electronic equipment better, the negative material of exploitation height ratio capacity becomes research emphasis.The research of current lithium ion battery negative material mainly concentrates on silicon based anode material, and silicon materials are because having higher lithium storage content, lower voltage platform and receive the very large concern of people.But pure silicon exists more serious bulk effect as negative material in the process of removal lithium embedded can lose electrical contact performance gradually along with the activated centre of cycle charge discharge electric material, finally makes the cycle performance of material sharply decline.Similar to other high-capacity lithium-ion negative material, at present in order to improve the poor shortcoming of silicon materials cycle performance, the methods such as main employing surface modification, doping, compound, form compound system that is coated or high dispersive, and then improve the electrochemical cycle stability of material.The exploitation of high power capacity silicium cathode material is a very long process, current research display carries out modification by diverse ways, the irreversible capacity of material can be reduced to a certain extent, improve the cycle performance of material, but with the graphite-phase of industrialization has a certain distance than still, this is also the common problem that high-capacity cathode material exists.
Electronic structure and the material surface performance of material internal can be changed for the material doped modification of high power capacity silicium cathode or alloying simultaneously, utilize and to form the element of stable compound and silicon with silicon and carry out alloying or partially-alloyed, the conductivity on the one hand utilizing metal material good and ductility so alleviate the own volumetric expansion of material in removal lithium embedded process internal stress to the destruction of material structure, the alloy material of cathode attempting utilizing the oxide of silicon or silicon and reducing metal materials synthesis to have high power capacity keeps higher theoretical capacity to overcome the poor deficiency of silicon materials efficiency cycle performance on the low side on the other hand on the one hand, reducing metal is utilized directly to prepare alloying composite electrode as the oxide reaction of matrix and silicon or silicon, and the alloy of this metal and silicon also has embedding lithium activity, the embedding lithium had under different potentials due to each component in composite material is active, scientific circles generally believe that this membrane electrode can the electrons spread ability of reinforcing material effectively, shorten the deintercalation path of lithium ion, alleviate the change in volume of material in charge and discharge process, thus make material have excellent chemical property.In addition, with regard to processing, this electrode in order to avoid close the techniques such as slurry, coating, can greatly simplify the Making programme of battery.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of lithium rechargeable battery Mg
2si/SiO
xthe preparation method of/C composite negative pole material membrane electrode.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is, lithium rechargeable battery Mg
2si/SiO
xthe preparation method of/C composite negative pole material membrane electrode, comprises the steps:
(1) to the clean of foam magnesium;
(2) utilize organic carbon source to prepare glue, add Si oxide or silica flour carries out dispersed with stirring, obtain the slurries evenly;
(3) slurries after are evenly coated on foam magnesium, through super-dry process, obtain presoma;
(4) dried presoma is carried out compaction treatment;
(5) presoma after compacting is sintered under inert gas shielding, naturally just obtain Mg after cooling
2si/SiO
x/ C composite negative pole material membrane electrode.
As preferably, in step (1), foam magnesium is tridimensional network or porous foam structure; The cleaning mode of foam magnesium foam magnesium is placed in organic solvent or weak acid carry out ultrasonic cleaning and dry process.
As preferably, in step (2), organic carbon source is one in sucrose, glucose, starch, phenolic resins, pitch, stearic acid, epoxy resin or two kinds and above mixture; Glue prepared by organic carbon source is for utilizing ethanol, methyl alcohol, acetone, toluene or water as solvent, different organic carbon sources is prepared into the solution of viscosity at 2000 ~ 10000Pas, wherein the amount of taking of organic carbon source is the oxide of silicon or 3% ~ 30% of silica flour quality, and mixing time is 1 ~ 10h; The purity of Si oxide or silica flour is the nanoscale of more than 99%.
As preferably, Si oxide is SiO
2, SiO.
As preferably, in step (3) evenly after slurry viscosity at 3000 ~ 30000Pas; Coating thickness is 10um ~ 200um; Vacuum drying temperature is 80 ~ 120 DEG C.
As preferably, in step (4), after compacting, the thickness of presoma is 1/10 ~ 1/2 of the presoma thickness before compacting.
As preferably, in step (5), inert gas is one or both and the above mixture in nitrogen, argon gas, helium; Sintering schedule is that first 1 ~ 8h is warming up to 200 ~ 400 DEG C, then is warming up to 400 ~ 1000 DEG C of insulation 1 ~ 48h, and heating rate is 2 ~ 20 DEG C/min.
The invention has the beneficial effects as follows:
Different with conventional high capacity negative material modification mode, the present invention is not only by adulterate to material itself or coatedly carry out modification, but utilize the reducing metal material with better conductive capability and three-dimensional structure as matrix, the oxide of silicon or silicon and metal reaction is made to generate the composite material of alloy and silicon, under each component in composite material has different potentials, embedding lithium is active, the new material obtained is while maintenance high power capacity, can also to alleviate in charge and discharge process due to bulk effect the negative interaction that material circulation performance is brought, improve the cycle performance of material.Sinter the membrane electrode that obtains to omit links such as closing slurry, coating, save traditional conducting metal substrate, reduce production cost.
Present invention process is simple, and synthesis flow is short, easy to operate, and environmental friendliness, reproducibility are strong, and can generally be suitable for.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
Fig. 1 is Mg prepared by the embodiment of the present invention 1
2si/SiO
xthe SEM photo of/C composite negative pole material membrane electrode.
Fig. 2 is Mg prepared by the embodiment of the present invention 1
2si/SiO
x/ C composite negative pole material membrane electrode first charge-discharge cyclic curve.
Fig. 3 is Mg prepared by the embodiment of the present invention 1
2si/SiO
x/ C composite negative pole material membrane electrode 100 cyclic curves.
Embodiment
Embodiment 1
Foam magnesium is placed in water and cleans 10 minutes under ultrasound condition, carry out drying process after taking-up for subsequent use.Sucrose in a heated condition water-soluble adjustment slurry viscosity at 3000Pas, after dissolving completely, add 10 times that amount that silicon dioxide wherein adds silicon dioxide is sucrose quality, regulate the viscosity of slurries at 7000Pas not stopping to add water under the condition stirred simultaneously.Regulate rear slurry to continue dispersed with stirring 4 hours, utilize Scraper applicator that even rear slurry is coated on the foam magnesium after process, put into dry 12h at vacuum drying chamber 120 DEG C.Dried diaphragm presoma through twin rollers roll-in to 1/3 of original thickness; put into tube furnace to sinter under argon shield, wherein sintering schedule is knot system is that 3 DEG C/min is warming up to 300 DEG C and is incubated 2h, is being warmed up to 650 DEG C of insulation 12h; Temperature fall, to room temperature, obtains Mg
2si/SiO
x/ C composite negative pole material membrane electrode.
Gained Mg
2si/SiO
x/ C composite negative pole material membrane electrode gets sheet by picture-taking device, and using lithium as to electrode, do electrolyte with 1M-LiPF6 EC/EMC solution, microporous polypropylene membrane is barrier film, is assembled into button cell.And leave standstill 6 hours.Be placed on LAND tester by standing rear battery and carry out electric performance test, carry out constant current charge-discharge experiment with the current density of 0.05C, test charging/discharging voltage scope is 0.01V ~ 1.5V.Fig. 1 illustrates the modification Mg that the present embodiment obtains
2si/SiO
x/ C composite negative pole material membrane electrode SEM photo, can find out that presoma is after sintering processes, generate homogeneous alloy compound phase; Figure 2 shows the present embodiment synthesis Mg
2si/SiO
xits first discharge specific capacity of first charge-discharge all fronts of/C composite negative pole material membrane electrode is 2200mAh/g, and efficiency is 84% first; Fig. 3 gives the present embodiment synthesis Mg
2si/SiO
xafter the circulation in 100 weeks of/C composite negative pole material membrane electrode, capacity remains on 2013mAh/g, and capability retention is 91.5%, and the material of this programme synthesis has more excellent cycle performance.
Embodiment 2
Foam magnesium is placed in water and cleans 10 minutes under ultrasound condition, carry out drying process after taking-up for subsequent use.Glucose in a heated condition water-soluble adjustment slurry viscosity at 4000Pas, add 15 times that amount that silicon monoxide wherein adds silicon monoxide is glucose quality after dissolving completely, regulate the viscosity of slurries at 6000Pas not stopping to add water under the condition stirred simultaneously.Regulate rear slurry to continue dispersed with stirring 3 hours, utilize Scraper applicator that even rear slurry is coated on the foam magnesium after process, put into dry 12h at vacuum drying chamber 120 DEG C.Dried diaphragm presoma through twin rollers roll-in to 1/4 of original thickness; put into tube furnace to sinter under argon shield, wherein sintering schedule is knot system is that 3 DEG C/min is warming up to 300 DEG C and is incubated 2h, is being warmed up to 600 DEG C of insulation 12h; Temperature fall, to room temperature, obtains Mg
2si/SiO
x/ C composite negative pole material membrane electrode.
Make button electricity by embodiment 1 and carry out electric performance test, discharge capacity is 1600mAh/g first, and efficiency is 82% first.
Embodiment 3
Foam magnesium is placed in water and cleans 10 minutes under ultrasound condition, carry out drying process after taking-up for subsequent use.Pitch is regulated slurry viscosity 5000Pas being dissolved in acetone, after dissolving completely, adds 20 times that amount that silica flour wherein adds silica flour is asphalt quality, regulate the viscosity of slurries at 10000Pas not stopping to add acetone under the condition stirred simultaneously.Regulate rear slurry to continue dispersed with stirring 6 hours, utilize Scraper applicator that even rear slurry is coated on the foam magnesium after process, put into dry 12h at vacuum drying chamber 120 DEG C.Dried diaphragm presoma through twin rollers roll-in to 1/4 of original thickness; put into tube furnace to sinter under argon shield, wherein sintering schedule is knot system is that 3 DEG C/min is warming up to 500 DEG C and is incubated 2h, is being warmed up to 700 DEG C of insulation 12h; Temperature fall, to room temperature, obtains Mg
2si/SiO
x/ C composite negative pole material membrane electrode.
Make button electricity by embodiment 1 and carry out electric performance test, discharge capacity is 1498mAh/g first, and efficiency is 83% first.
Embodiment 4
Foam magnesium is placed in water and cleans 10 minutes under ultrasound condition, carry out drying process after taking-up for subsequent use.Phenolic resins slurries ethanol adjusting viscosity 3000Pas, after dissolving completely, add 12 times that amount that silicon monoxide wherein adds silicon monoxide is asphalt quality, regulate the viscosity of slurries at 8000Pas not stopping to add ethanol under the condition stirred simultaneously.Regulate rear slurry to continue dispersed with stirring 10 hours, utilize Scraper applicator that even rear slurry is coated on the foam magnesium after process, put into dry 12h at vacuum drying chamber 120 DEG C.Dried diaphragm presoma through twin rollers roll-in to 1/3 of original thickness; put into tube furnace to sinter under argon shield, wherein sintering schedule is knot system is that 3 DEG C/min is warming up to 450 DEG C and is incubated 2h, is being warmed up to 650 DEG C of insulation 12h; Temperature fall, to room temperature, obtains Mg
2si/SiO
x/ C composite negative pole material membrane electrode.
Make button electricity by embodiment 1 and carry out electric performance test, discharge capacity is 1605mAh/g first, and efficiency is 83% first.
Embodiment 5
Foam magnesium is placed in water and cleans 10 minutes under ultrasound condition, carry out drying process after taking-up for subsequent use.Pitch is regulated slurry viscosity 4000Pas being dissolved in methyl alcohol, after dissolving completely, adds 20 times that amount that silicon dioxide wherein adds silicon dioxide is asphalt quality, regulate the viscosity of slurries at 6000Pas not stopping to add methyl alcohol under the condition stirred simultaneously.Regulate rear slurry to continue dispersed with stirring 7 hours, utilize Scraper applicator that even rear slurry is coated on the foam magnesium after process, put into dry 12h at vacuum drying chamber 120 DEG C.Dried diaphragm presoma through twin rollers roll-in to 1/2 of original thickness; put into tube furnace to sinter under argon shield, wherein sintering schedule is knot system is that 3 DEG C/min is warming up to 500 DEG C and is incubated 2h, is being warmed up to 700 DEG C of insulation 12h; Temperature fall, to room temperature, obtains Mg
2si/SiO
x/ C composite negative pole material membrane electrode.
Make button electricity by embodiment 1 and carry out electric performance test, discharge capacity is 1390mAh/g first, and efficiency is 81% first.
Above-described embodiment of the present invention, does not form limiting the scope of the present invention.Any amendment done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within claims of the present invention.