47 results about "Difluorophosphate" patented technology

The present invention belongs to the field of lithium ion batteries, and specifically relates to an in-situ preparation method and a recovery method for a solid polymer electrolyte, as well as a lithium ion battery. The preparation method provided by the present invention comprises the following steps: a) loading an electrolyte precursor onto a surface of a battery separator, and then assembling same with a lithium ion battery positive electrode and a lithium ion battery negative electrode, to obtain a semi-finished lithium ion battery product, components of the electrolyte precursor in step a) comprising a polymer monomer, a lithium salt and an initiator, the lithium salt being lithium perchlorate, lithium hexafluorophosphate, lithium difluorophosphate, or the like; b) under heating conditions, performing in-situ polymerization of the electrolyte precursor on the battery separator in the semi-finished lithium ion battery product, to obtain a solid polymer electrolyte loaded on the battery separator. The preparation method provided by the present invention does not require an additional catalyst, and the prepared solid polymer electrolyte can be depolymerized by means of heating, and has good environmental and economic benefits.

The invention belongs to the technical field of chemical materials, and particularly discloses a method for preparing lithium sulfide, which comprises the following steps: mixing lithium salt and ammonium sulfide for reaction to obtain lithium sulfide; wherein the lithium salt comprises at least one of lithium hexafluorophosphate, lithium difluorophosphate and lithium tetrafluoroborate. According to the method for preparing the lithium sulfide, the lithium salt and the ammonium sulfide can fully react under the mild condition, the reaction time is short, the reaction yield is high, and meanwhile the purity of the obtained lithium sulfide is high.

The present invention relates to the technical field of compound preparation, specifically discloses a method for producing three (trimethylsilyl) phosphate using fluorosilane tail gas, comprising the following steps: at 60 ℃ 110 ℃ temperature, 0.1MPa 2.0MPa pressure, the production tail gas containing trimethylsilyl fluorosilane is passed into polyphosphoric acid and reacted, after the completion of the reaction, three (trimethylsilyl) phosphate and phosphorus oxyfluoride are obtained. The present invention effectively processes the production tail gas containing trimethylsilyl fluorosilane, converts the trimethylsilyl fluorosilane in the tail gas into three (trimethylsilyl) phosphate with high added value, not only solves the tail gas treatment problem, but also increases economic benefit, while saving tail gas treatment cost. In addition, the present invention realizes the efficient recovery of fluorine resources, and the byproduct phosphorus oxyfluoride produced in the preparation process can be directly put into production again as the raw material for synthesizing lithium difluorophosphate, forming a closed-loop recycling of fluorine resources, further reducing production costs, and improving resource utilization.

The application belongs to the technical field of chemical materials, and specifically discloses a method for preparing lithium sulfide, which comprises the following steps: mixing and reacting lithium salt and ammonium sulfide to obtain lithium sulfide; wherein the lithium salt comprises at least one of lithium hexafluorophosphate, lithium difluorophosphate and lithium tetrafluoroborate. In the method for preparing lithium sulfide, the lithium salt and the ammonium sulfide can be fully reacted under mild conditions, the reaction time is short, the reaction yield is high, and the obtained lithium sulfide has high purity.

The invention relates to the technical field of electrochemistry, in particular to an electrolyte and a secondary battery. The electrolyte comprises an organic solvent, an electrolyte and additives, the additives comprise a first additive, a second additive and a film-forming additive, the first additive is selected from at least one of compounds shown in the formula I, the second additive is selected from at least one of compounds shown in the formula II, and the film-forming additive is selected from at least one of compounds shown in the formula II. The film-forming additive is selected from at least one of vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, ethylene sulfate, 1, 3-propane sultone, lithium difluorophosphate and lithium bis (oxalato) borate, and the first additive, the second additive and the film-forming additive have a synergistic effect, so that a composite film with a stable structure can be formed on the surface of an electrode; and the transmission of lithium ions on an electrode / electrolyte interface is facilitated, so that the high-temperature performance of the secondary battery and the cycle performance of the secondary battery under high voltage are improved.

The present disclosure relates to a lithium secondary battery in which an abnormal voltage drop phenomenon is improved. The lithium secondary battery comprises a negative electrode comprising a negative electrode active material, a positive electrode comprising a positive electrode active material represented by Formula 1, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution comprises a lithium salt, a non-aqueous organic solvent, a compound represented by Formula 2 as a first additive, and lithium difluorophosphate as a second additive:LiaNixCOyM1zM2wO2  [Formula 1]wherein all the variables are described herein.

The invention relates to a secondary battery and an electronic device. Specifically, the secondary battery provided by the invention comprises a positive electrode, a negative electrode and an electrolyte, the positive electrode comprises a positive electrode current collector, and an insulating layer and a positive electrode material layer which are arranged on the positive electrode current collector; the insulating layer comprises boehmite, the positive electrode material layer comprises lithium iron phosphate and lithium manganate, and the electrolyte comprises lithium difluorophosphate. According to the invention, the floating charging safety of the secondary battery can be improved, and the particle breaking change rate can be reduced.

The invention discloses a local high-concentration electrolyte containing a phosphorus-based additive, a preparation method and application of the local high-concentration electrolyte and a lithium metal battery, and belongs to the technical field of high-specific-energy secondary batteries. The electrolyte contains a lithium salt, an ether solvent, a fluoroether diluent and a certain amount of lithium difluoro bis (oxalate) phosphate. The electrolyte provided by the invention has higher oxidation stability under high voltage, and has good compatibility with an iron fluoride positive electrode and a lithium metal negative electrode. The lithium difluoro oxalate phosphate additive is introduced to regulate and control the solvation structure of the local high-concentration electrolyte, an F / P inorganic component-rich electrode-electrolyte interface is formed, and after the assembled FeF3 / Li battery circulates for 400 circles at the rate of 1C, the specific discharge capacity reaches up to 371 mAh g <-1 >, and the capacity retention ratio is 82%.

Electrolyte composition for batteries, the electrolyte composition comprising: ethylene carbonate; Diethyl carbonate; Ethyl methyl carbonate; vinylethylene carbonate; vinyl carbonate; Propane-1,3-sultone; ethylene sulfate; and lithium difluorophosphate; and wherein the ethylene carbonate, the diethyl carbonate and the ethyl methyl carbonate are each present in the electrolyte composition in an amount of 10 parts by weight to 50 parts by weight based on 100 parts by weight of the electrolyte composition; wherein the ethylene carbonate, the diethyl carbonate and the ethyl methyl carbonate are present in a ratio of 1:1:1; wherein the vinylethylene carbonate is present in the electrolyte composition at 0.5 parts by weight based on 100 parts by weight of the electrolyte composition; wherein the vinyl carbonate is present in the electrolyte composition at 1.0 part by weight based on 100 parts by weight of the electrolyte composition; and wherein the propane-1,3-sultone is present in the electrolyte composition at 1.5 parts by weight based on 100 parts by weight of the electrolyte composition.

The invention relates to a method for preparing a high-purity lithium difluoro (oxalato) borate solid through a low-temperature melting method, and belongs to the technical field of lithium battery electrolyte additives. The preparation method comprises the following steps: under the protection of argon, adding lithium oxalate, boric acid and lithium fluoride into a reaction kettle, uniformly stirring and mixing, and carrying out a low-temperature melting reaction to form a molten reaction product; naturally cooling the molten reaction product to room temperature, cooling and crystallizing, and separating out solid crystals; washing the solid crystals with absolute ethyl alcohol, performing centrifugal separation, and removing surface impurities through a modified resin adsorbent; drying the washed solid crystals in a vacuum drying oven to obtain a high-purity lithium difluoro (oxalato) borate solid; the modified resin adsorbent is prepared from styrene-divinylbenzene copolymer resin, dichloroethane, allyl phosphine dichloride, benzoyl peroxide and tetraallyl silicate. The lithium difluoro (oxalato) borate prepared by the method is high in purity and high in yield, and meets the use requirements of a high-energy-density lithium ion battery electrolyte.

The present invention relates to a lithium secondary battery in which the phenomenon of abnormal voltage drop is reduced. The lithium secondary battery comprises a negative electrode including an active material for the negative electrode, a positive electrode including an active material for the positive electrode represented by chemical formula 1, a separator interposed between the negative and positive electrodes, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution includes: a lithium salt; a non-aqueous organic solvent; a compound represented by chemical formula 2 as a first additive; and lithium difluorophosphate as a second additive.

The invention relates to a negative pole piece and an electrochemical device and electronic equipment comprising the same, and belongs to the technical field of electrochemical energy storage. The negative pole piece comprises a negative current collector and a negative active layer arranged on at least one surface of the negative current collector, wherein the negative active layer comprises a negative active material, a lithium salt, a functional additive and a dry binder; the lithium salt comprises at least one of lithium bis (trifluoromethanesulfonyl) imide, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium difluorosulfonyl imide, lithium tetrafluoroborate, lithium difluorophosphate and lithium trifluoromethanesulfonate. The negative pole piece provided by the invention can avoid the risk of lithium salt hydrolysis in a traditional scheme, after the battery is packaged, the solid lithium salt is directionally released and high ion conduction SEI is formed in situ through a controllable heat-pressure activation program, the first efficiency, the cycling stability and the system reliability are improved, and the liquid injection time is remarkably shortened.

The invention relates to the field of lithium ion batteries, and discloses a battery cell and a lithium ion secondary battery. The battery cell comprises a diaphragm and an electrolyte, the mass content B of a lithium salt in the electrolyte is 8-18%, and the lithium salt comprises at least one of lithium hexafluorophosphate and lithium difluorophosphate; the diaphragm comprises a base membrane and a ceramic layer, the ceramic layer comprises SiO2, a Si-O bond in the SiO2 comprises a Q4 covalent bond structure, and the mass content A of the Q4 covalent bond structure is 26.4-89% by taking the mass of the Si element in the ceramic layer as a reference; 11.13 > = A / B > = 1.47. By adjusting the mass content A of the Q4 covalent bond structure in the diaphragm ceramic layer, the mass content B of the lithium salt in the electrolyte and the A / B value to be within the range, the rate capability, the cycle stability and the low-temperature discharge performance of the battery can be comprehensively improved.

The present disclosure relates to an electrolyte suitable for a lithium primary battery. In order to solve the problems of poor safety performance, high-rate discharge and poor discharge performance of electrolytes of the existing lithium primary batteries under a high-temperature condition, the electrolyte includes an electrolyte lithium salt, an additive, and an organic solvent, wherein the electrolyte lithium salt includes one or more of lithium trifluoromethanesulfonate, lithium bis(triflu-oromethanesulphonyl)imide, lithium difluorophosphate, and lithium difluoro(oxalato)borate; the additive includes one or more of (2-trimethylsilylethyl)2-cyanoacetate, diphenyldimethoxysilane, and citraconic anhydride; and the organic solvent comprises a carbon-ate solvent and a glycol ether solvent. A selective combination of the electrolyte lithium salt, the additive, and the solvent, normal-temperature discharge can be met when the electrolyte is applied to the lithium primary battery. The lithium primary battery can take into account the constant / high temperature performance, high-rate discharge performance and safety performance.

A lithium secondary battery electrolyte solution includes an organic solvent and a first additive, a second additive, and an electrolyte salt that are dissolved in the organic solvent. The organic solvent includes a carboxylate solvent. A mass percent W1 of the carboxylate solvent in the organic solvent is 20% to 80%. The first additive includes one or more of monofluorophosphate, difluorophosphate, tetrafluoroborate, fluorosulfonate, oxalate borate, malonate borate, oxalate phosphate, or malonate phosphate. The second additive includes one or more of vinylene carbonate or a derivative thereof, or ethylene carbonate or a derivative thereof. The mass percent of the first additive and the mass percent of the second additive in the electrolyte solution are W2 or W3 respectively, satisfying: 0.035≤(W2+W3) / W1≤0.15.

The present invention belongs to the field of lithium-ion batteries, and particularly relates to an in-situ preparation method of a solid polymer electrolyte, its recycling method, and a lithium-ion battery. The preparation method provided by the present invention comprises the following steps: a) loading an electrolyte precursor onto the surface of a battery separator, and then assembling it with a lithium-ion battery positive electrode and a lithium-ion battery negative electrode to obtain a semi-finished lithium-ion battery; in step a), the components of the electrolyte precursor include a polymerizable monomer, a lithium salt, and an initiator, and the lithium salt is lithium perchlorate, lithium hexafluorophosphate, lithium difluorophosphate, etc.; b) under heating conditions, the electrolyte precursor in the semi-finished lithium-ion battery undergoes in-situ polymerization on the battery separator to obtain a solid polymer electrolyte loaded on the battery separator. The preparation method provided by the present invention does not require an external catalyst, and the obtained solid polymer electrolyte can be depolymerized by heating, having good environmental and economic benefits.

The invention relates to a method for efficiently preparing lithium difluoro (oxalato) borate, which comprises the following steps of: adding lithium tetrafluoroborate and anhydrous aluminum oxalate into an organic solvent to form a uniform reaction system, carrying out heating reaction under the protection of inert atmosphere, carrying out solid-liquid separation after the reaction is finished, and carrying out vacuum concentration, crystallization, filtration and drying on filtrate to obtain lithium difluoro (oxalato) borate crystals. According to the method, lithium difluoro (oxalato) borate and aluminum fluoride are prepared through reaction of lithium tetrafluoroborate and anhydrous aluminum oxalate (Al2 (C2O4) 3), the method has the advantages of being mild in reaction condition, easy to operate, low in raw material cost, high in yield, environmentally friendly and the like, the defects in the prior art can be overcome, and the method is suitable for large-scale industrial production.

The invention relates to the technical field of compound preparation, and particularly discloses a method for producing tris (trimethylsilyl) phosphate by using fluoroalkyl silane tail gas, which comprises the following steps: introducing production tail gas containing trimethylfluoroalkyl silane into polyphosphoric acid for reaction at the temperature of 60-110 DEG C and the pressure of 0.1-2.0 MPa, and after the reaction is completed, separating and purifying to obtain tris (trimethylsilyl) phosphate. The tris (trimethylsilyl) phosphate and the phosphorus trifluoride oxide are obtained. According to the method, the production tail gas containing the trimethylfluorosilane is effectively treated, and the trimethylfluorosilane in the tail gas is converted into the tris (trimethylsilyl) phosphate with high additional value, so that the problem of tail gas treatment is solved, the economic benefit is increased, and meanwhile, the tail gas treatment cost is saved. Besides, efficient recovery of fluorine resources is realized, and the byproduct phosphorus trifluoride generated in the preparation process can be directly used as a raw material for synthesizing lithium difluorophosphate to be put into production again, so that closed-loop cyclic utilization of the fluorine resources is formed, the production cost is further reduced, and the resource utilization rate is improved.

The application discloses a local high-concentration lithium metal battery electrolyte and a preparation method and application thereof. The electrolyte comprises a lithium salt, an organic solvent, an additive and a diluent; the organic solvent comprises at least one of methyl formate, methyl acetate, methyl propionate, methyl butyrate, ethyl propionate, ethyl acetate, ethyl butyrate, methyl trifluoroacetate and ethyl trifluoroacetate; the additive comprises at least one of fluoroethylene carbonate, lithium difluorobisoxalate phosphate and lithium difluorophosphate; and the diluent is a fluorine-containing ether compound. The local high-concentration electrolyte has the advantages of high-voltage resistance of high-concentration electrolyte and inhibition of corrosion of sulfonimide-based electrolyte on aluminum foil, meanwhile, the problems of high viscosity, low conductivity and poor impregnation with a separator of high-concentration electrolyte are overcome, the cycle performance and low-temperature performance of the lithium metal battery are significantly improved, and the local high-concentration electrolyte is particularly suitable for application in a low-temperature high-voltage lithium battery. The preparation method is simple, the cost is low, and the method is suitable for industrial production.

The invention relates to a positive pole piece and an electrochemical device and electronic equipment comprising the same, and belongs to the technical field of electrochemical energy storage. The lithium ion battery comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode active material, a lithium salt, a functional additive and an ionic conductor; the lithium salt comprises at least one of lithium bis (trifluoromethanesulfonyl) imide, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium difluorosulfonyl imide, lithium tetrafluoroborate, lithium difluorophosphate and lithium trifluoromethanesulfonate. The lithium source can be released from the positive electrode, high-yield mass production compatibility can be achieved, only the pure organic solvent needs to be injected in the liquid injection stage, the system viscosity is reduced, the infiltration time is shortened, and the ion transport uniformity is improved; and in combination with a thermal activation process, lithium salt directional migration and interface in-situ film formation are triggered after winding and packaging, so that higher battery performance indexes are realized.

The present invention provides a lithium secondary battery including a negative electrode, a positive electrode facing the negative electrode, a separator interposed between the negative electrode and the positive electrode, and a non-aqueous electrolyte. The negative electrode contains a negative electrode active material, the negative electrode active material contains a silicon-based active material, the non-aqueous electrolyte contains a lithium salt, an organic solvent, and an additive, the additive contains a first additive and a second additive, the first additive contains a coumarin-based compound represented by a specific chemical formula, and the second additive contains at least one selected from the group consisting of lithium fluoromalonate(difluoro)borate (LiFMDFB), lithium difluoro(oxalate)borate (LiDFOB), lithium difluorophosphate (LiDFP), and lithium difluorobis-(oxalate)phosphate (LiDFOP). The secondary battery according to the present invention can improve high-temperature cycle characteristics and high-temperature storage characteristics by forming a flexible and highly durable film on the negative electrode containing the silicon-based active material.

A non-aqueous electrolyte solution comprises additives, wherein the additives comprise a first additive and a second additive, the first additive is any one or more cyclic sulfate compounds having a structure represented by general formula (I), and the second additive comprises one or more of lithium monofluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, a compound represented by general formula (II), and fluorosulfonates.

The invention discloses a low-temperature safe lithium iron phosphate battery electrolyte and a preparation method thereof, and belongs to the technical field of lithium battery electrolyte. The electrolyte is composed of three parts, namely a ternary composite solvent, a ternary composite lithium salt and a functional composite additive, wherein the ternary composite solvent is composed of an ether-based solvent, a phosphate solvent and a carbonate solvent, and the ternary composite lithium salt is composed of lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide and lithium difluoro (oxalato) borate. According to the preparation method, a step-by-step charging process is adopted, a solvent, a lithium salt and an additive are sequentially added according to a specific sequence, and a finished product is prepared through aging inspection, filtering and filling. According to the invention, low-temperature ion conduction and flame-retardant safety are synergistically improved through the ternary composite solvent, wide-temperature-range high conductivity and aluminum foil compatibility are considered through the ternary composite lithium salt, and a gradient double-layer interfacial film with inorganic inside and organic outside is constructed through reduction potential gradient difference of the functionalized additive so as to reduce low-temperature interface impedance; and a lithium ion solvation structure is regulated and controlled through a step-by-step preparation process, so that the low-temperature performance and the batch stability are improved.

The invention discloses a high-energy-density lithium iron phosphate cylindrical battery and a preparation method thereof, and relates to the technical field of lithium iron phosphate batteries, the battery is of a full-tab or tab-free winding structure, the end face of a micro tab at the positive electrode end and an aluminum or aluminum alloy collector ring are pressed tightly and are subjected to laser welding at a welding window; an annular two-layer gradient micropore composite interface layer is arranged on the end face of the collector ring and comprises a bonding passivation seed layer and a heat-conducting and electricity-conducting micropore network layer, the two layers both contain aluminum fluoride particles and lithium phosphate particles, and the outer layer contains hexagonal boron nitride, aluminum nitride and a conductive carbon skeleton. The diaphragm is provided with an anode end function band, and the electrolyte contains lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide, lithium difluorophosphate and lithium difluoro (oxalato) borate; and pre-charging and pulse directional activation formation are carried out after liquid injection infiltration. The battery inhibits end hot spots and corrosion and reduces end temperature difference under fast charging and high power, connection resistance drift and gas production are reduced, a fast charging window is improved, the cycle life is prolonged, and the consistency is improved.

The application provides a lithium ion battery electrolyte and application thereof, and the electrolyte comprises: a nonaqueous solvent; a lithium salt; and an additive, wherein the additive comprises a first additive and a second additive; the first additive is selected from compounds represented by any one of formulas (I) to (III); and the second additive comprises lithium difluorophosphate dioxalate; wherein R1 to R7 are substituents with 1 to 3 carbon atoms, 0 to 4 unsaturation degrees and 0 to 3 heteroatom numbers; R8 is a cyclic substituent with 0 to 4 unsaturation degrees and 0 to 5 heteroatom numbers; when the unsaturation degree of R8 is 0, R9 is a vinyl group, a propenyl group, a butenyl group, a 1,3-butadienyl group, an ethynyl group or a propynyl group; when the unsaturation degree of R8 is 1 to 4, the R9 substituent is absent; the heteroatom is selected from at least one of nitrogen, sulfur, phosphorus, chlorine, fluorine and oxygen; and n is 0 to 2. The lithium ion battery electrolyte and application thereof simultaneously consider the low-temperature performance, high-temperature performance and gas production performance of the lithium ion battery.

The invention provides an electrolyte for a lithium metal battery, a preparation method of the electrolyte, a lithium metal battery monomer and an electric device. The electrolyte comprises a lithium salt, a first solvent and an ionic liquid additive, the compound has a chemical formula shown in a formula (a), R comprises C5-C10 alkylene which is not substituted or substituted by halogen atoms, R1 is a conjugated group, and R2 is an alkyl group. R2 comprises a bis (fluorosulfonyl) imide ion, a bis (trifluoromethyl) sulfonyl imide ion, a trifluoroborate ion, a hexafluorophosphate ion, a sulfonate ion, a hexafluoroarsenate ion, a trifluoromethanesulfonate ion, a difluorophosphate ion, a bis (oxalato) borate ion, a difluoro (oxalato) borate ion and a difluoro (oxalato) phosphate ion; the ionic liquid is any one of tetrafluoro oxalic acid phosphate ions; and R3 comprises any one of quaternary ammonium ions, pyrrolidinyl, pyrrolyl, piperidinyl, pyridyl and imidazolyl. The electrolyte can slowly release the lithium salt and prolong the cycle life of the lithium metal battery monomer. The invention also provides a lithium metal battery monomer containing the electrolyte and an electric device.

The invention discloses a solvent composition and positive electrode slurry. The solvent composition comprises a first component and a second component, wherein the first component comprises a silicon-based difluorophosphate compound; the second component is prepared from one of beta-alkoxy propionamide and alpha-alkoxy acetamide, and the second component is prepared from one of beta-alkoxy propionamide and alpha-alkoxy acetamide; wherein the mass ratio of the first component to the second component is (0.2: 100)-(10: 100). Therefore, the positive electrode slurry adopting the solvent composition has relatively excellent stability, the baking effect after coating is relatively good, and the cycle performance of the battery can be improved by the decomposition product of the first component.

The invention provides a non-aqueous electrolyte solution and a non-aqueous electrolyte solution battery which can exhibit excellent normal-temperature cycle characteristics and low-temperature input characteristics after a cycle test when made into a non-aqueous electrolyte solution battery. The nonaqueous electrolyte solution contains: (I) at least one compound selected from the group consisting of a monofluorophosphate, a difluorophosphate, a monofluorosulfonate, a salt represented by general formula (1) described in the description, and a salt represented by general formula (2) described in the description; (II) a solute; (III) a non-aqueous organic solvent; and (IV) a compound represented by general formula (3) described in the description. The non-aqueous electrolyte solution battery contains the non-aqueous electrolyte solution.

The application discloses a solvent composition and a positive electrode slurry. The solvent composition comprises: a first component, the first component comprising a silicon-based difluorophosphate compound; and a second component, the second component comprising one of a beta-alkyloxypropionamide and an alpha-alkyloxyacetamide; wherein the mass ratio of the first component to the second component is (0.2:100) to (10:100). Thus, the positive electrode slurry adopting the solvent composition has better stability, the baking effect after coating is better, and the decomposition product of the first component can improve the cycle performance of a battery.

The invention discloses positive electrode slurry, a positive electrode plate and a battery. The positive electrode slurry comprises a positive electrode active material and an additive, the additive comprises a silicon-based difluorophosphate compound, the silicon-based difluorophosphate compound satisfies a formula I and a formula I, R1, R2 and R3 are independently selected from C1-C4 alkyl, C1-C4 fluoroalkyl, C2-C4 alkenyl, C2-C4 fluoroalkenyl, C2-C4 alkynyl, C2-C4 fluoroalkynyl,-OP (= O) F2,-Si (R4) (R5) OP (= O) F2 or-OSi (R4) (R5) OP (= O) F2; r < 4 > and R < 5 > are respectively and independently selected from alkyl of C < 1 > to C < 4 >, fluoroalkyl of C < 1 > to C < 4 >, alkenyl of C < 2 > to C < 4 >, fluoroalkenyl of C < 2 > to C < 4 >, alkynyl of C < 2 > to C < 4 >, fluoroalkynyl of C < 2 > to C < 4 > or-OP (= O) F2. Therefore, the positive electrode slurry has relatively excellent stability, the baking effect after coating is relatively good, the cycle performance of the battery can be improved by the decomposition product of the additive, and the battery prepared from the positive electrode slurry has relatively excellent cycle performance and relatively high energy density.