A kind of preparation method of the lithium ion battery containing functional additive
Technical field
The present invention relates to technical field of lithium-ion battery, particularly relate to a kind of lithium ion battery containing additive and preparation method thereof.
Background technology
In recent years, lithium ion battery is the excellent characteristics such as energy density is high, output voltage is high, self-discharge rate is low, long service life, memory-less effect and environmental friendliness and obtain people and pay close attention to greatly because having, development is advanced by leaps and bounds, the market share constantly expands, progressively replace NI-G (Ni-Cd) and metal nickel-Hydrogenized compound (Ni-MH) battery, occupy leading position.It is widely used in the mobile electronic terminal devices such as notebook computer, mobile phone, video camera, instrument and meter, electric tool.In addition, lithium ion battery applications also constantly expands in the demand of the high-tech industries such as electric automobile (EV), energy storage, military project, and not only developing into the main flow industry in China's new energy materials field, is also one of theme of countries in the world technology contest.
Along with developing rapidly of modern mobile electronic device, communication apparatus and electrokinetic cell industry, higher, more fully requirement is proposed to lithium ion battery.Now lithium battery is proposed to the high-energy-density requirement of more than 200Wh/Kg, and circulation comprises high temperature, normal temperature, low-temperature circulating performance will be got well, and to adapt to the needs under varying environment, also has most important security performance.
Take carbon-based material as the lithium battery of negative pole, layer protecting film can be formed at the interface of electrode and electrolyte in initial charge process, be called SEI film, SEI film has the meaning of particular importance in lithium ion battery, the chemical composition of SEI film, structure, the physicochemical properties such as texture and stability are the keys determining compatibility of electrolytewith carbon negative electrode in Li-ion batteries, optimize SEI film character, realize compatibility good between electrolyte and electrode and the kind of widening electrolyte is one of important development direction of lithium ion battery, the key addressed this problem selects and prepares excellent film for additive, electrode is made to set up excellent SEI film prior to solvation lithium ion intercalation in initial charge process, permission lithium ion frees in and out electrode and solvent molecule cannot pass through, thus stop solvent molecule to the destruction of electrode, improve doff lithium capacity and the cycle life of electrode.Meanwhile, people also generally believe that surface also can form SEI film at a lot of positive pole (as cobalt acid lithium, nickle cobalt lithium manganate, LiMn2O4, LiFePO4, cobalt phosphate lithium, LiNiPO, rich lithium manganese, nickel manganese binary material).This tunic can protect the metal ion in positive pole not dissolved by electrolyte, prevent electrolyte be oxidized by the positive pole of Charging state and heat release.The performance of character to battery of SEI film serves vital effect, so people can add the functional additive that some can improve SEI film in the process preparing lithium battery.Different additive roles is different, comprises and improves battery normal temperature, high temperature or low-temperature circulating performance, raising battery safety.
Current most of producer adds functional additive in the electrolytic solution, but adds by this way, and additive major part is residual in the electrolytic solution, only has a very little part through reaction in electrode surface film forming.This causes the amount adding additive comparatively large, and generally need mass ratio more than 1%, the additive added caused negative effect also more serious more, as degradation under the reduction of electrolyte ion conductivity, stability.Given this, we can add additive in electrode homogenization process, additive electrode surface all participate in reaction and formed stablize good SEI film, it greatly reduces the consumption of additive, and formed SEI film can wrap up all electrode-electrolyte interface equably.Describe in Chinese patent CN102044675A and in positive pole homogenate, add imide analog compounds can improve battery high-temperature behavior, overcharging resisting performance and security performance, but do not relate to the formation of SEI film.Document " Review of selected electrode-solution interactions which determine the performance of Li and Li ion batteries " (D.Aurbach, J.Power Sources, 89, 206, 2000) propose, add additive in the electrodes and also there is a shortcoming, exactly along with the carrying out of battery charging and discharging, lithium ion ceaselessly penetrates and passes the SEI film of electrode surface, SEI film is destroyed and need to repair, additive in electrode lacks mobility cannot complete repair process, this causes the cycle performance of battery, security performance declines, the effect of additive reduces.
summary of the invention
Good SEI film can be formed to make lithium battery; and protect in battery use procedure and repair SEI film; we have proposed a kind of lithium ion battery containing additive and preparation method thereof; adopt the present invention can improve many-sided performance of lithium battery; comprise normal temperature and high/low temperature cycle performance, the security performance of battery; also can reduce the consumption of functional additive, reduce costs.
The present invention is achieved by the following technical solutions: the invention provides a kind of lithium ion battery containing additive, be made up of, add identical or different additive simultaneously, make battery in battery electrode homogenization process and in the electrolytic solution electrode and electrolyte.Additive electrode surface all participate in reaction and formed stablize good SEI film, greatly reduce the consumption of additive, and the SEI film formed can wrap up all electrode-electrolyte interface equably, add in electrolyte after additive makes SEI film in the electrodes destroyed and repaired by additive reaction remaining in electrolyte.
The above-mentioned electrode containing additive can be positive pole and the negative pole of lithium battery, and also can be one of them in both, SEI film generally believes mainly for the protection of negative pole carbon-based material, equally, also can form SEI film, improve battery performance greatly at positive pole.
The preparation method of a kind of lithium ion battery containing additive of the present invention is as follows:
Negative pole prepares: added in negative pole glue by the additive of certain mass, stir, add conductive agent, negative electrode active material, binding agent by a certain percentage afterwards, and uniform stirring forms slurry, and coating afterwards obtains negative pole.
Positive pole prepares: conductive agent, positive electrode active materials and anode additive are added by a certain percentage in the positive pole glue containing binding agent, uniform stirring obtains anode sizing agent, and coating afterwards obtains positive pole.
Electrolyte prepares: the additive adding relative certain mass in the electrolytic solution.
Described positive electrode active materials is containing cobalt acid lithium (LiCoO
2), nickle cobalt lithium manganate [LiNi
xco
ymn
(1-x-y)o
2], LiMn2O4 (LiMn
2o
4), LiFePO4 (LiFePO
4), rich lithium manganese (xLi
2mnO
3yLiMO
2), orthophosphates (LiCoPO
4and LiNiPO
4), nickel manganese binary material (LiNi
0.5mn
1.5o
4) middle at least one; At least one in described negative active core-shell material graphitiferous, soft or hard carbon, silicon-carbon cathode composite; Additive in electrode can improve the SEI film that electrode and electrolyte interface are formed in battery first charge-discharge process, the SEI film that the additive in electrolyte damages after can repairing discharge and recharge; Because adding the difference of additive, one or more effects following can be played: improve battery normal temperature, high temperature or low-temperature circulating performance, improve battery safety.
Described additive is following several: ES (ethylene sulfite), PS (propylene sulfite), VC (vinylene carbonate), methyl phenyl ethers anisole, DMTFA (N; N-dimethyl trifluoroacetamide), BTE (1,2-trifluoroacetyl group ethane), C1-EC (chloroethylene carbonate ester), 12-Cr-4 (12-crown-4 ether), SO
2, CO
2, Li
2cO
3, LiBOB (dioxalic acid lithium borate) etc.
In electrode homogenization process He in electrolyte, add one or more additives simultaneously, preferably add additive of the same race in the electrodes with in electrolyte.One or more additives can be added in unitary electrode, also can all add several additive at both positive and negative polarity, but additive must be added in the electrolytic solution, preferably add the additive identical with in electrode.
The mass ratio that often kind of additive accounts for electrode active material is 0.05 ~ 0.5%, and preferred proportion is 0.1 ~ 0.25%, and the mass ratio that the often kind of additive added in the electrolytic solution accounts for electrolyte is 0.1 ~ 2.5%, and preferred proportion is 0.1 ~ 0.5%.Additive adds too much can waste material, and cannot improve effect; Additive adds the too low effect not reaching additive, little on battery performance impact.
Compared with prior art, beneficial effect of the present invention is:
(1) good SEI film is stablized in formation, improves cycle performance of battery and battery capacity.
(2) in charge and discharge process, repair SEI film, improve battery normal temperature, high temperature or low-temperature circulating performance, and security performance.
(3) saved the consumption of additive while in order to be effective, reduced costs.
(4) this method is a kind of universal method preparing lithium battery, adopts the inventive method can realize diversified object, improves the combination property of lithium battery.
embodiment
Below in conjunction with embodiment, further illustrate content of the present invention.Should be appreciated that enforcement of the present invention is not limited to the following examples, any pro forma accommodation make the present invention or change all fall into scope; And the method in following embodiment, if no special instructions, be the conventional method of this area.
Embodiment 1:
Negative pole prepares: will be the lithium carbonate (Li of 0.1% relative to active material mass ratio
2cO
3) additive adds in sodium cellulosate (CMC) aqueous solution (hereinafter referred to as negative pole glue), stir, add conductive agent, active material graphite, binding agent afterwards by a certain percentage, uniform stirring forms slurry, and coating afterwards obtains negative pole.
Positive pole prepares: by conductive agent, positive active material nickle cobalt lithium manganate Li (Ni
0.5co
0.2mn
0.3) O
2add by a certain percentage in 1-METHYLPYRROLIDONE (NMP) solution containing binding agent, uniform stirring obtains anode sizing agent, and coating afterwards obtains positive pole.
Electrolyte prepares: electrolyte is for having dissolved lithium hexafluoro phosphate (LiPF
6) ethylene carbonate-methyl ethyl carbonate (EC-EMC) mixed solution, add relative to electrolyte quality than the Li being 0.2% wherein
2cO
3additive.
Above ready electrode and electrolyte are assembled 3 bag soft-package batteries by existing battery production technology, and carry out normal temperature circulation, measuring capacity is averaged.
Embodiment 2:
Embodiment 2 step is substantially the same manner as Example 1, different be to join the Li in negative pole glue
2cO
3additive, the mass ratio of relative activity material is 0.15%.
Embodiment 3:
Embodiment 3 step is substantially the same manner as Example 1, different be to add the Li in negative pole glue
2cO
3additive, the mass ratio of relative activity material is 0.2%.
Comparative example 1:
Comparative example 1 is substantially identical with embodiment 1 step, and institute's difference is all not add Li in negative pole and electrolyte
2cO
3additive.Above test result is listed in Table 1.
Comparative example 2:
Comparative example 2 is substantially identical with embodiment 1 step, and institute's difference is not add Li in negative pole glue
2cO
3additive.Above test result is listed in Table 1.
Comparative example 3:
Comparative example 3 is substantially identical with embodiment 1 step, and institute's difference is not add Li in electrolyte
2cO
3additive, and add the Li in negative pole glue
2cO
3additive, the mass ratio of relative activity material is 0.2%.Above test result is listed in Table 1.
Table 1:
Embodiment 4:
Negative pole prepares: the aqueous solution configuring sodium cellulosate (CMC), adds conductive agent, active material graphite, binding agent by a certain percentage, and uniform stirring forms slurry, and coating afterwards obtains negative pole.
Positive pole prepares: added by the LiBOB additive relative to active material mass ratio being 0.1% in 1-METHYLPYRROLIDONE (NMP) solution (hereinafter referred to as positive pole glue) containing binding agent, conductive agent, positive active material nickle cobalt lithium manganate Li (Ni
0.5co
0.2mn
0.3) O
2uniform stirring obtains anode sizing agent by a certain percentage, and coating afterwards obtains positive pole.
Electrolyte prepares: electrolyte is for having dissolved lithium hexafluoro phosphate (LiPF
6) ethylene carbonate-methyl ethyl carbonate (EC-EMC) mixed solution, add relative to electrolyte quality than the LiBOB additive being 0.2% wherein.
Above ready electrode and electrolyte are assembled 3 bag soft-package batteries by existing battery production technology, and carry out 45 DEG C of high temperature circulation, measuring capacity is averaged.
Embodiment 5:
Embodiment 5 step is substantially the same manner as Example 4, the different LiBOB additive being to add in positive pole glue, the mass ratio of relative activity material is 0.15%.
Embodiment 6:
Embodiment 6 step is substantially the same manner as Example 4, the different LiBOB additive being to add in positive pole glue, the mass ratio of relative activity material is 0.2%.
Embodiment 7:
Negative pole prepares: will be the lithium carbonate (Li of 0.1% relative to active material mass ratio
2cO
3) additive adds in sodium cellulosate (CMC) aqueous solution (hereinafter referred to as negative pole glue), adds conductive agent, active material graphite, binding agent by a certain percentage, uniform stirring forms slurry, and coating afterwards obtains negative pole.
Positive pole prepares: added by dioxalic acid lithium borate (LiBOB) additive relative to active material mass ratio being 0.1% in 1-METHYLPYRROLIDONE (NMP) solution containing binding agent, conductive agent, positive active material nickle cobalt lithium manganate Li (Ni
0.5co
0.2mn
0.3) O
2uniform stirring obtains anode sizing agent by a certain percentage, and coating afterwards obtains positive pole.
Electrolyte prepares: electrolyte is for having dissolved lithium hexafluoro phosphate (LiPF
6) ethylene carbonate-methyl ethyl carbonate (EC-EMC) mixed solution, add wherein relative to electrolyte quality than being the LiBOB additive of 0.15% and the Li of 0.15%
2cO
3additive.
Above ready electrode and electrolyte are assembled 3 bag soft-package batteries by existing battery production technology, and carry out 45 DEG C of high temperature circulation, measuring capacity is averaged.
Comparative example 4:
Comparative example 4 step is substantially the same manner as Example 4, and institute's difference is all not add LiBOB additive in positive pole and electrolyte.Above test result is listed in table 2.
Comparative example 5:
Comparative example 5 step is substantially the same manner as Example 4, and institute's difference is not add LiBOB additive at positive pole.Above test result is listed in table 2.
Comparative example 6:
Comparative example 6 step is substantially the same manner as Example 4, and institute's difference is not add LiBOB additive in electrolyte, and adds the LiBOB additive in positive pole glue, and the mass ratio of relative activity material is 0.2%.。Above test result is listed in table 2.
Table 2:
Embodiment 8:
Negative pole prepares: added by ethylene sulfite (ES) additive relative to active material mass ratio being 0.1% in sodium cellulosate (CMC) aqueous solution (hereinafter referred to as negative pole glue), stir, add conductive agent, active material graphite, binding agent by a certain percentage, uniform stirring forms slurry, and coating afterwards obtains negative pole.
Positive pole prepares: by conductive agent, positive active material nickle cobalt lithium manganate Li (Ni
0.5co
0.2mn
0.3) O
2add by a certain percentage in 1-METHYLPYRROLIDONE (NMP) solution containing binding agent, uniform stirring obtains anode sizing agent, and coating afterwards obtains positive pole.
Electrolyte prepares: electrolyte is for having dissolved lithium hexafluoro phosphate (LiPF
6) propene carbonate (PC) solution, add relative to electrolyte quality than the ES additive being 0.2% wherein.
Above ready electrode and electrolyte are assembled 3 bag soft-package batteries by existing battery production technology, and carry out-20 DEG C of low-temperature circulatings, measuring capacity is averaged.
Embodiment 9:
Embodiment 9 step is substantially the same manner as Example 8, the different ES additive being to add in negative pole glue, the mass ratio of relative activity material is 0.15%.
Embodiment 10:
Embodiment 10 step is substantially the same manner as Example 8, the different ES additive being to add in negative pole glue, the mass ratio of relative activity material is 0.2%.
Comparative example 7:
Comparative example 7 step is substantially the same manner as Example 8, and institute's difference is all not add ES additive in negative pole and electrolyte.Above test result is listed in table 3.
Comparative example 8:
Comparative example 8 step is substantially the same manner as Example 8, and institute's difference is in negative pole, do not add ES additive.Above test result is listed in table 3.
Comparative example 9:
Comparative example 9 step is substantially the same manner as Example 8, and institute's difference is not add ES additive in the electrolytic solution, and adds the ES additive in negative pole glue, and the mass ratio of relative activity material is 0.2%.Above test result is listed in table 3.
Table 3:
Can find out that the lithium battery that the manufacture method that the method for the application of the invention and tradition do not add functional additive is produced significantly promotes normal temperature, high temperature or low-temperature circulating performance.