460 results about "Lithium hexafluorophosphate" patented technology

The embodiment of the invention provides an electrolyte, a battery and a power utilization device, the electrolyte comprises a lithium salt, a first additive and a second additive, the lithium salt comprises lithium hexafluorophosphate, the second additive is lithium fluorosulfonate, and the first additive has a structure as shown in a formula (1). The first additive and the second additive have a synergistic effect, an organic-inorganic composite CEI film is formed on the positive electrode, meanwhile, an inorganic SEI film with high ionic conductivity is formed on the negative electrode, and the CEI film and the SEI film can reduce side reactions between the electrode and an electrolyte, so that damage to the surface structure of the electrode and decomposition gas production of the electrolyte are reduced, and the service life of the electrolyte is prolonged. The cycle performance of the battery is improved; and the inorganic SEI film with high ionic conductivity can improve the transmission rate of conductive ions, so that the power performance of the battery is improved, and the battery has relatively good cycle performance and power performance.

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, the positive pole piece comprises a positive active material layer, and the positive active material layer comprises lithium-containing phosphate of an olivine structure; the electrolyte comprises, by mass, 8-30% of a carboxylic ester solvent, a lithium salt and an unsaturated ester additive, the lithium salt comprises lithium hexafluorophosphate and fluorine-containing lithium sulfimide, the mass content of the fluorine-containing lithium sulfimide in the lithium salt is 18-45%, the mass content of the unsaturated ester additive in the electrolyte is 0.05-5%, and the mass content of the unsaturated ester additive in the electrolyte is 0.05-5%. The unsaturated ester additive comprises one or more of vinylene carbonate, vinylethylene carbonate, allyl ethyl carbonate and a fluoro-carbonate additive; the amount of electrolyte in the battery cell is 2.8 g / Ah to 3.2 g / Ah. According to the invention, rapid charging and use reliability of the single battery can be considered.

The invention relates to a preparation technology of a gel polymer lithium ion battery cell electrolyte, and belongs to the field of battery preparation technologies, the preparation technology comprises the following steps: mixing methacrylate monomers and silane monomers according to a mass ratio of 3: 1-5: 1, adding 1-3% of an initiator, and carrying out prepolymerization at 60-80 DEG C for 1-3 h to prepare a prepolymer solution; mixing with a non-aqueous solvent containing lithium hexafluorophosphate according to a mass ratio of (1: 4)-(1: 6) to form a precursor mixed solution, and controlling the injection rate to be 1.5-2.5 g / Ah to a gap between a battery cell pole piece and a diaphragm; after standing for 2-4 hours at the vacuum degree of less than or equal to-0.08 MPa, curing for 3-6 hours at the temperature of 60-70 DEG C to form a gel polymer electrolyte; the wettability is improved through pole piece surface hydrophilic treatment, 1-5% of vinylene carbonate is added to optimize an SEI film, the prepolymerization temperature fluctuation is controlled to be smaller than or equal to + / -2 DEG C through microwave-assisted heating, the pressure of 0.2-0.5 MPa is applied after injection to promote uniform permeation, a polyvinylidene fluoride coating of 5-10 microns is coated after curing to enhance protection, and the interface performance is ensured through an alternating-current impedance test.

The invention discloses an electrolyte for a lithium manganate lithium ion battery and a preparation method thereof, and the electrolyte comprises the following components in percentage by mass: 70-90% of an organic solvent, 5-20% of a lithium salt and 0.5-10% of an additive, the organic solvent is formed by mixing cyclic carbonate and chain carbonate according to the mass ratio of (10-30): (70-90); the lithium salt adopts one or more of lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF) and lithium bis (trifluoromethane sulfonimide) (LiTFSI), and the concentration of the lithium salt is 0.8 to 1.5 mol / L; the additives comprise a manganese ion complexing agent, a film forming accelerant and an antioxidant. In the invention, the manganese ion inhibition effect is as follows: the complexing agent and Mn (II) ions form a stable complex, so that the concentration of free Mn (II) in the electrolyte is reduced by more than 80%, migration and deposition of the free Mn (II) to the negative electrode are inhibited, and the dissolution amount of the Mn element of the positive electrode is reduced by 65% after 500 times of circulation at 45 DEG C.

The invention discloses a lithium ion battery electrolyte, a preparation method and application. The lithium ion battery electrolyte comprises a lithium salt and an organic solvent, wherein the lithium salt comprises a combination of at least two of lithium hexafluorophosphate, lithium difluoro bis (oxalato) phosphate, lithium bis (fluorosulfonyl) imide and lithium bis (oxalato) borate, and the organic solvent comprises 30 wt%-50 wt% of hydrofluoroether, 10 wt%-30 wt% of acetate and 20 wt%-60 wt% of carbonate. The lithium ion battery electrolyte provided by the invention can keep the diaphragm structure complete, realizes filling of pores with lithium salt, and reduces the permeability of the diaphragm, thereby controlling possible shrinkage of the diaphragm in a temperature change process under a low-temperature or high-temperature condition; the crosstalk problem caused by gas penetration between the positive electrode and the negative electrode is inhibited, and the battery prepared by utilizing the lithium ion battery electrolyte provided by the invention has good cycle performance and rate capability under a low-temperature condition and has relatively high safety under a high-temperature condition.

A non-woven battery separator and processes for forming the non-woven battery separator includes a fiber blend including cellulose fibers, microfibrillated fibers, and optionally polyester and / or aramid fibers. Also disclosed are batteries including the non-woven battery separator. During fabrication, the non-woven battery separator can be effectively dried at temperatures between 120°C and 180°C, which results in the fibers absorbing water when in use. Some battery electrolytes such as lithium hexafluorophosphate react with water to form hydrogen fluoride (HF), which can be corrosive and shorten battery lifecycles and affect performance. Absorbing water from the electrolyte increases the battery life cycle by reducing HF generation.

The invention belongs to the technical field of electrolyte, and particularly relates to a method for preparing liquid lithium hexafluorophosphate from sodium hexafluorophosphate. The method comprises the following steps: adding a sodium source into a hexafluorophosphoric acid aqueous solution for neutralization reaction to obtain a sodium hexafluorophosphate aqueous solution, then extracting to remove water, drying to obtain a sodium hexafluorophosphate solid, and heating and decomposing the sodium hexafluorophosphate solid to obtain phosphorus pentafluoride gas; the phosphorus pentafluoride gas is not mixed with SO3, POF3, HF and other impurity gases, a complex refining and purifying process is not needed, and the phosphorus pentafluoride gas with the purity exceeding 99.9% can be obtained after simple purification and can be directly used for synthesizing liquid lithium hexafluorophosphate. The method does not generate waste acid, does not need a complicated phosphorus pentafluoride gas purification process, is particularly suitable for the requirements of the lithium battery industry on high-purity electrolyte, and has the remarkable advantages of high product purity, small environmental pollution, low production cost and the like.

The application provides a lithium ion battery and an electric device, the lithium ion battery comprising a positive electrode sheet and an electrolyte, an active substance in the positive electrode sheet comprising a phosphate lithium positive electrode material and a lithium nickel cobalt manganese oxide, the electrolyte comprising a positive electrode film former, a negative electrode film former and a lithium salt, the lithium salt comprising lithium hexafluorophosphate and a lithium bisfluorosulfonylimide salt, the lithium ion battery satisfying the following formula: wherein NL is a mass ratio of the lithium nickel cobalt manganese oxide and the phosphate lithium positive electrode material, S alt is a value of a molar concentration of the lithium hexafluorophosphate and the lithium bisfluorosulfonylimide salt in the electrolyte in mol / L, and A dd is a mass ratio of the positive electrode film former and the negative electrode film former. The application can adjust the ratio of the positive electrode film former and the negative electrode film former and the ratio of the high-heat-resistance lithium salt according to the mixing ratio of the ternary material doped in the lithium manganese iron phosphate or the lithium iron phosphate, so that the cycle performance of the battery is improved.

A novel additive, an electrolyte, and a lithium ion battery, relating to the technical field of lithium ion batteries. The electrolyte comprises a lithium salt and a non-aqueous solvent for dissolving the lithium salt, the electrolyte further comprises an electrolyte additive, the electrolyte additive comprises a positive electrode film-forming additive and a negative electrode film-forming additive, and the electrolyte additive further comprises a fluoro isocyanate-based pyridazine organic compound. The additive can absorb moisture and hydrofluoric acid in the electrolyte, reduce the dissolution of transition metals, improve the thermal stability of lithium hexafluorophosphate, and maintains the stability of a ternary material under high voltage; a sulfuric acid group on the novel additive can be oxidized by oxygen at a positive electrode, so that the oxygen generated when an LFO lithium supplementing agent is activated is absorbed, the capacity exertion, high temperature cycle and high temperature storage of the LFO lithium supplementing agent are significantly improved, and the DCIR of the battery will not obviously increase, thereby improving the stability of the battery.

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.

A battery cell, a battery, and an electric device. The battery cell comprises a positive electrode sheet, a negative electrode sheet, and an electrolyte; the positive electrode sheet comprises a positive electrode active material layer; the positive electrode active material layer comprises a lithium-containing material of an olivine structure; the negative electrode sheet comprises a negative electrode active material layer; the size of the positive electrode active material layer in the length direction of the positive electrode sheet is L1 mm, the size of the positive electrode active material layer in the width direction of the positive electrode sheet is W1 mm, the size of the negative electrode active material layer in the length direction is L2 mm, the size of the negative electrode active material layer in the width direction is W2 mm, 1<(L2-L1) / (W2-W1)≤4, L2 / L1>1, and 500≤L1≤600; the electrolyte comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and based on the total mass of the electrolyte, the ratio of the mass content of the lithium hexafluorophosphate to the mass content of the lithium bis(fluorosulfonyl)imide is greater than 1. The usage reliability of the battery cell can be improved.

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, an isolating membrane and a negative pole piece, the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one side of the positive current collector, the negative pole piece comprises a negative current collector and a negative active material layer arranged on at least one side of the negative current collector, the positive active material layer comprises lithium-containing phosphate with an olivine structure, the electrolyte comprises a silane-based additive, and the mass content of the silane-based additive in the electrolyte is 0.05-1%; the electrolyte further comprises lithium salt, the lithium salt comprises lithium hexafluorophosphate, the mass content of the lithium hexafluorophosphate in the electrolyte is 8%-12%, and the total mass content of the lithium salt in the electrolyte is 10%-18%. The use reliability of the battery cell can be improved.

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 invention discloses splitting, shock excitation and separation integrated equipment for lithium hexafluorophosphate-based electrolyte recovery, and relates to the technical field of lithium hexafluorophosphate-based electrolyte recovery, the splitting, shock excitation and separation integrated equipment comprises a conveying table and a sealing cover, the top of the conveying table is provided with the sealing cover, the top of the conveying table is provided with a position control mechanism, and the position control mechanism comprises a track conveying plate arranged at the top of the conveying table; an abutting block is arranged on a second sliding block installed at the top of the rail conveying plate, and transmission columns are symmetrically welded and fixed to the side of the abutting block. By integrating components such as the position control mechanism, the cutting vibration mechanism and the lifting frame, clamping, girdling, vibration separation and heating recovery of the battery are automatically completed, manual intervention is reduced, the overall battery treatment efficiency is improved, meanwhile, low-temperature baking condensation is adopted subsequently, an organic solvent is sublimated or volatilized under strict temperature control, and the battery quality is improved. And the lithium hexafluorophosphate is recycled through a condensing system, so that subsequent separation of the lithium hexafluorophosphate is facilitated.

The present application provides a secondary battery and an electric device. The secondary battery comprises a positive electrode sheet, a negative electrode sheet, and an electrolyte. The positive electrode sheet contains lithium-containing transition metal phosphate; and the lithium-containing transition metal phosphate contains submicron-sized particles and micron-sized particles. In addition, the electrolyte in the secondary battery contains a lithium salt and a film-forming stabilizer; and the lithium salt comprises a first lithium salt and a second lithium salt, wherein the first lithium salt contains lithium hexafluorophosphate, and the second lithium salt contains one or both of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethylsulfonyl)imide. The secondary battery designed in the present application is advantageous in taking into account the energy density, the rate performance and the cycle performance of the battery.

The invention relates to a method for efficiently synthesizing a lithium difluoro bis (oxalate) phosphate solid in a continuous flow reactor, and belongs to the field of environmental protection. The method comprises the following steps: firstly, feeding a lithium hexafluorophosphate solution and a lithium oxalate solution into a static mixing module of a continuous flow reactor for mixing; then entering a reaction module of the continuous flow reactor for reaction; after the reaction is finished, the material enters a separation module of a continuous flow reactor, and after membrane separation, crude lithium difluorobisoxalato phosphate is obtained through a modified ceramic membrane adsorbent; washing the crude lithium difluoro-bis (oxalate) phosphate with absolute ethyl alcohol, and performing vacuum drying to obtain a lithium difluoro-bis (oxalate) phosphate solid; the modified ceramic membrane adsorbent is prepared from an aluminum oxide-zirconium oxide composite ceramic membrane, DMF (Dimethyl Formamide), water, isocyanate 1-trimethoxysilyl methyl ester, 3, 5-dihydroxyphenylboronic acid and stannous octoate. The lithium difluoro-bis (oxalate) phosphate prepared by the method is high in purity and high in yield, and meets the requirements of high-end lithium batteries.

Provided are a battery cell, a battery device, and an electric device. The battery cell comprises a positive electrode sheet and an electrolyte; the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer located on at least one surface of the positive electrode current collector; the positive electrode active layer comprises a positive electrode active material; the positive electrode active material comprises a lithium-containing phosphate; the single-sided surface density of the positive electrode active layer ranges from 230 mg / 1540.25 mm2 to 400 mg / 1540.25 mm2; the electrolyte comprises a solvent and a lithium-containing electrolyte salt; the solvent comprises a chain carboxylic acid ester and ethylene carbonate; the lithium-containing electrolyte salt comprises one or more of lithium hexafluorophosphate and a fluorine-containing sulfonimide salt; the mass ratio of the lithium-containing electrolyte salt to the ethylene carbonate is 0.29-0.72; and the conductivity of the electrolyte ranges from 13 mS / cm to 20 mS / cm.

The invention discloses a lithium ion battery electrolyte and a lithium ion battery. The lithium ion battery electrolyte comprises an organic solvent, a composite lithium salt and an additive, the composite lithium salt comprises lithium hexafluorophosphate, lithium bis (fluorosulfonyl) imide and lithium nitrate; the additive comprises a compound 1. By adopting the low-concentration composite lithium salt and the electrolyte containing the compound 1, the oxygenolysis of the electrolyte is inhibited, the solvation energy of solvated lithium ions is reduced, the kinetics of the electrolyte is improved, and the rate discharge, high temperature and cycle performance of the battery are improved.

The invention discloses a novel solvent system-based low-temperature lithium battery electrolyte and a production process, the novel solvent system-based low-temperature lithium battery electrolyte comprises the following components: a carbonic ester solvent, a lithium salt combination and an additive, the carbonic ester solvent comprises ethylene carbonate, fluoroethylene carbonate, 1, 3-dioxolame and ethyl methyl carbonate, and the lithium salt combination comprises a lithium salt combination and an additive; the lithium salt combination is a mixed system of lithium bis (fluorosulfonyl) imide and lithium hexafluorophosphate, and the additives are vinylene carbonate, succinonitrile, lithium nitrate, triphenyl phosphate and aluminum trifluoromethanesulfonate; according to the low-temperature lithium battery electrolyte, the performance bottleneck of a traditional electrolyte at the temperature of-40 DEG C to-30 DEG C is broken through through multi-level cooperation of solvent-lithium salt-additive preparation of the low-temperature lithium battery electrolyte, the solvent maintains low viscosity while reducing the freezing point, and low-temperature high dissociation and interface stability are achieved through lithium salt compounding; the compatibility of the solid electrolyte interfacial film structure and current collection is finely regulated and controlled through the additive, and the application requirement in the extremely cold environment is met.

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a method for synthesizing lithium hexafluorophosphate from lithium tripolyphosphate. The synthesis method comprises the following steps: uniformly mixing lithium tripolyphosphate and phosphorus pentoxide in an ether solvent to obtain a first mixture; introducing a mixed gas of hydrogen fluoride and nitrogen into the first mixture, and carrying out a mixed reaction to obtain a second mixture; and carrying out solid-liquid separation on the second mixture, and carrying out reduced-pressure concentration, recrystallization and reduced-pressure drying on the filtrate after solid-liquid separation to obtain lithium hexafluorophosphate. The lithium tripolyphosphate, the phosphorus pentoxide and the hydrogen fluoride are used as raw materials, the hydrogen fluoride gas is uniformly introduced for reaction, the lithium hexafluorophosphate is directly synthesized in the ether solvent, and the method has the advantages of mild reaction conditions, high reaction efficiency, high product purity and high yield. The problems of more byproducts, high cost and the like in the industrial production process of lithium hexafluorophosphate are solved.

To provide a lithium ion battery with improved cycle performance.SOLUTION: The battery comprises an electrolyte and a positive electrode plate, wherein the electrolyte comprises lithium hexafluorophosphate as a lithium salt, and a mass content of the lithium hexafluorophosphate is 15% to 20% of a total mass of the electrolyte, the positive electrode plate comprises a positive current collector and a positive electrode film disposed on at least one side of the positive current collector and comprising a positive active material, and the positive active material comprises a compound having a molecular formula of LidNiaCobMncM (1-a-b-c) Qz; 0 <d ≤ 2.1, 0.6 <a <1, 0 <b <1, 0 <c <1, and 0.6 <a + b + c <1, 1.8 ≤ z ≤ 3.5, the element M includes at least one of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce, and the element Q includes at least one of O and F.SELECTED DRAWING: None

To provide an electrolytic solution and a lithium ion battery capable of overcoming a problem that a melting point of the electrolyte solution is high, an ionic conductivity is low, and a performance at low temperature is poor.SOLUTION: An electrolytic solution includes a solvent, a lithium salt, and an additive. The solvent includes a cyclic carbonate, a linear carbonate, and ethyl acetate. The cyclic carbonate includes ethylene carbonate, and the lithium salt includes lithium bis (fluorosulfonyl) imide and lithium hexafluorophosphate. A mass percentage of the cyclic carbonate accounts for 5% to 10% of the total amount of the solvent. The mass percentage of the linear carbonate accounts for 20% to 60% of the total amount of the solvent. The mass percentage of the ethyl acetate accounts for 50% to 95% of the total amount of the solvent, and the mass percentage of the lithium bis (fluorosulfonyl) imide accounts for 8% to 20% of the total amount of the electrolytic solution.SELECTED DRAWING: None

This invention proposes a lithium-ion battery electrolyte and its application. The electrolyte comprises at least the following components: a fluorinated solvent, including 2,2-difluoroethyl acetate, fluoroethylene carbonate, and 2,2-difluoroethyl ethyl carbonate; a lithium salt, including a first lithium salt comprising lithium hexafluorophosphate; and an additive, including a first additive comprising lithium difluorobis(oxalato)phosphate. The lithium-ion battery electrolyte and its application proposed in this invention can improve the electrolyte's high-voltage resistance and kinetic performance, reduce battery impedance, and enhance the battery's fast-charging performance and high-temperature cycle stability.

This invention relates to a wide-temperature-range, high-power, low-temperature charge-discharge-cycle-capable starting lithium-ion battery. The invention comprises a positive electrode, a negative electrode, and an electrolyte, characterized in that: the positive electrode is composed of a lithium iron phosphate material body, a conductive agent, carbon nanotubes, a binder, and aluminum foil; the lithium iron phosphate material body is composed of lithium iron phosphate, titanium, and highly conductive carbon; the content of highly conductive carbon is 1.3–2.0%; the negative electrode is composed of artificial graphite, a conductive agent, sodium carboxymethyl cellulose, a binder, and copper foil, with 91–93 parts of artificial graphite, 2–5 parts of conductive agent, 0.5–1.5 parts of sodium carboxymethyl cellulose, and 2–3 parts of binder; the electrolyte is composed of lithium hexafluorophosphate, lithium salt additives, film-forming additives, and a low-melting-point solvent, with the concentration of lithium hexafluorophosphate being above 1.3 mol / L, lithium salt additives being 0.5–9 parts, and film-forming additives being 0.2–3 parts. This invention expands the operating temperature range of lithium-ion batteries to -40℃ to 65℃.

The invention relates to the technical field of chemical machinery, in particular to automatic filtering and drying equipment and method.The automatic filtering and drying equipment comprises a rotary cylinder capable of working in multiple postures, double-layer sleeve fluid conveying assemblies are arranged at the two ends of the cylinder respectively, one end assembly is specially used for liquid phase conveying, central pipe liquid feeding and interlayer liquid discharging, and the other end assembly is specially used for gas / solid phase conveying; the central pipe discharges solid and the interlayer exhausts air, so that thorough isolation of a high-risk liquid phase and a gas / solid phase pipeline is realized on a physical structure, a follow-up heating and control system, an airflow conveying and discharging mechanism and a built-in crushing mechanism are integrated, and full-process automatic closed operation of inverted filtering, rotary drying and upright discharging is realized. The problems of liquid crystallization blockage, sealing failure leakage, danger of manual operation and the like caused by mixed use of pipelines of traditional equipment are fundamentally solved, and the device is particularly suitable for safe and efficient production of lithium hexafluorophosphate and other materials which are high in toxicity, high in corrosion, flammable and explosive, easy to deliquesce and cannot be in contact with air.

The invention discloses an electrolyte for a lithium battery, which comprises an organic solvent, a lithium salt and an additive, and the mass percentage ratio of the organic solvent to the lithium salt to the additive is (70-90): (5-20): (0.2-10); the organic solvent is composed of cyclic carbonate and chain carbonate in a mass ratio of (10-30): (70-90); the lithium salt is one or more of lithium hexafluorophosphate, lithium perchlorate and lithium tetrafluoroborate; the additives comprise a high-temperature stabilizer, an antioxidant and a film-forming accelerant, the cyclic carbonate is one or two of ethylene carbonate and propylene carbonate, and the chain carbonate is one or more of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate and methyl propyl carbonate. By optimizing the components of the electrolyte, the stability of the electrolyte at a high temperature is improved, and decomposition and side reactions are reduced, so that the performance of the battery in a high-temperature environment is improved, and the cycle life of the battery in a high-temperature environment is prolonged.

An electrolyte for a battery cell, a battery cell for a vehicle and a method of forming a battery cell. The electrolyte includes a combination of lithium ion salts including lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide, and lithium difluoro(oxalato)borate. The electrolyte also includes a carbonate solvent including fluoroethylene carbonate, ethyl methyl carbonate, and a carboxylic acid ester exhibiting the following formula:wherein R1 and R2 are individually an unsubstituted alkyl group including in the range of 1 carbon to 2 carbons, wherein the combination of lithium ion salts is dispersed in the carbonate solvent. The electrolyte further includes vinylene carbonate. The electrolyte does not include ethyl carbonate.

A lithium-ion battery with an electrode assembly is shown. The electrode assembly has a current collector and a positive active material layer on the current collector. The electrode assembly also has an electrolyte containing lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide in a ratio of 0.8 M to 0.2 M and a fluorinated phosphazene additive at 7 wt.% dissolved in a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and sulfolane in a volume ratio of 25 / 73 / 2. The electrolyte permeates a surface of the positive active material layer to suppress electrochemical oxidation of the positive active material layer.

The application provides a silicon composite negative electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery electrode materials. The method comprises the following steps: vacuum thermal reduction of graphene oxide to obtain graphene nanosheets; mixing of a strong acid and a silicon-based material, while adding the graphene nanosheets, stirring for 5min-60min, and then filtering and washing the turbid liquid to obtain a precipitate; adding lithium hexafluorophosphate into an organic solvent, placing the organic solvent in a sealed container, adding the precipitate and aluminum oxide at 60-180 DEG C, and reacting for 2-10h, and then drying to obtain the silicon composite negative electrode material. The silicon composite negative electrode material has high initial coulomb efficiency and good cycle stability.

The invention relates to a continuous crystallization system and method of lithium hexafluorophosphate, and belongs to the technical field of lithium ion battery electrolyte production. Aiming at the characteristics and requirements of a lithium hexafluorophosphate cooling crystallization process, the invention provides a continuous crystallization system of lithium hexafluorophosphate, which separates cooling nucleation from cooling crystallization. An ultrasonic generating device is introduced into the cooling nucleation module, lithium hexafluorophosphate is stimulated and induced by ultrasonic waves to nucleate, limitation of a metastable region is reduced, the nucleation rate is increased, crystal nuclei are controlled to be within a small particle size distribution range, meanwhile, introduction of impurities in the nucleation process is reduced, and the product purity is guaranteed. And the lithium hexafluorophosphate solution to be crystallized can continuously and uninterruptedly enter the cooling nucleation module, the cooling crystallization module and the separation circulation module in sequence, so that the continuous crystallization of the lithium hexafluorophosphate is realized, the crystallization time is greatly shortened, and the crystallization efficiency is improved.