242 results about "Ethylene carbonate" patented technology

Secondary battery, including a positive electrode sheet comprising a positive electrode current collector and a positive electrode film layer, wherein the positive electrode film layer is arranged on at least one side of the positive electrode current collector and the positive electrode film layer comprises a positive electrode active material; a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer, wherein the negative electrode film layer is arranged on at least one side of the negative electrode current collector and the negative electrode film layer comprises a negative electrode active material, wherein the negative electrode active material comprises graphite and the powder compaction density of the negative electrode active material at 20,000 N is 1.5 g / cm³ 3 up to 1.85 g / cm³ 3 is; and an electrolyte comprising an organic solvent and an organic additive, wherein the organic solvent comprises a first solvent, the first solvent comprising cyclic carbonate, and the mass fraction of the first solvent, based on the total mass of the electrolyte, is 17% to 34%; wherein the organic additive comprises a first and a second additive, the first additive comprising vinylene carbonate and the second additive comprising an ethylene carbonate derivative, and the mass fraction of the first additive is 1.5% to 8% and the mass fraction of the second additive is 0.5% to 4%, each based on the total mass of the electrolyte.

The invention discloses a preparation method of a piezoelectric response type hybrid ceramic membrane, which is characterized in that polyvinylidene fluoride powder is used as a base material of the membrane, propylene carbonate or ethylene carbonate is used as a diluent, negative-voltage-loaded piezoelectric ceramic modified nanoparticles are doped, and a proper amount of inorganic piezoelectric nanoparticles are doped, so that the electrical property of the pressed membrane is remarkably improved; a negative charge group introduced to the surface of the membrane through surface grafting is combined, so that the relative content of beta crystal forms of the polyvinylidene fluoride membrane is increased, and finally efficient interception and excellent anti-pollution effects on humic acid are achieved.

The invention relates to a method and a system for preparing chloroethylene carbonate through continuous photochlorination. The system aims at solving the three technical problems that the mass transfer efficiency of chlorine is low under the high gas-liquid ratio, reaction balance is inhibited by accumulation of hydrogen chloride by-products, and selectivity is reduced due to excessive chlorination. The method provided by the invention comprises the following steps: dispersing chlorine into bubbles of 50 microns or below by adopting a metal sintering microbubble generator; a light source and a hollow fiber membrane separation assembly are arranged in the reactor, chlorine and ethylene carbonate are subjected to a reaction through photo-initiation to generate chloroethylene carbonate, and meanwhile generated hydrogen chloride is removed through membrane in-situ displacement by means of purging gas; the system adopts a two-section series structure, and the reaction depth is cooperatively controlled through sectional chlorine gas introduction and gradient illumination intensity. The method provided by the invention realizes efficient utilization of chlorine, real-time breaking of reaction balance and high-selectivity synthesis of monochlorinated products, and is suitable for continuous, safe and efficient industrial production of chloroethylene carbonate.

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 belongs to the technical field of nano materials and environment-friendly functional coatings, and discloses a preparation method and application of a lignin-based super-hydrophobic coating. The method comprises the steps that lignin is pretreated with ethylene carbonate to break steric hindrance and improve the grafting rate, then hexadecyl trimethoxy silane is added for grafting to form a hydrophobic chain, and surface energy is reduced; then adding silicon dioxide and N, N-dimethylformamide, carrying out ultrasonic dispersion to synergistically construct a micro-nano coarse structure, spraying the micro-nano coarse structure on a base material by using a spraying method, and putting the base material into a drying oven for curing, so as to obtain the lignin-based super-hydrophobic coating material. According to the method disclosed by the invention, a high-activity epoxy group is grafted on a lignin skeleton through ethylene carbonate pretreatment, so that steric hindrance in a three-dimensional space is broken, and dense anchor points are provided for a subsequent hydrophobic chain; then cocondensing with hexadecyl trimethoxy silane to form an alkyl-siloxane double network, and cooperating with nano silicon dioxide to construct micro-nano double roughness, so that a stable super-hydrophobic core under a fluorine-free condition is realized, and the technical route is simple and efficient.

The invention discloses a bimetallic asymmetric reduction Schiff base catalyst for synthesizing ethylene carbonate and a preparation method of the bimetallic asymmetric reduction Schiff base catalyst. According to the catalyst, a diamine compound is subjected to selective single-side protection, the imine reduction position is controlled, and a bimetallic active center is introduced; the controllable synthesis of a product for reducing the outer side imine and a product for reducing the inner side imine is realized; the obtained product is recrystallized to obtain a monoimine-monoamine type ligand with a clear asymmetric structure, the monoimine-monoamine type ligand and metal salt form a bimetallic catalyst, and the catalyst generates a synergistic effect through double active sites and shows high catalytic activity and excellent product selectivity.

This disclosure relates generally to battery cells, and more particularly, electrolyte additives for use in lithium-ion battery cells.

The application provides a virus-removing polyether sulfone porous membrane and a preparation method thereof. The virus-removing polyether sulfone porous membrane comprises, in sequence along a thickness direction, an outer layer region and an inner layer region, wherein the average pore size of the outer layer region is 10-20 nm, the thickness of the outer layer region is 20-50 microns, the average pore size of the inner layer region is 5-10 microns, and the thickness of the inner layer region is 60-150 microns; and the virus-removing polyether sulfone porous membrane is prepared by a method comprising at least the following process: taking polyether sulfone as a raw material, and obtaining the virus-removing polyether sulfone porous membrane under the action of a water-soluble diluent and a hydrophilic additive; wherein the water-soluble diluent comprises ethylene carbonate and polyethylene glycol. The virus-removing polyether sulfone porous membrane has a high virus removal rate and a high protein permeation rate.

The invention relates to polyfurandicarboxylic acid glycol ester resin as well as a preparation method and application thereof, and belongs to the technical field of organic high-molecular compounds. The preparation method of the polyethylene furandicarboxylate resin provided by the invention comprises the following steps: S1, mixing 2, 5-furandicarboxylic acid, ethylene glycol, a catalyst and an inhibitor, and carrying out esterification reaction to obtain an ester; and S2, carrying out low-pressure condensation polymerization on the ester obtained in the step S1 to obtain the polyethylene furandicarboxylate resin, the inhibitor is ethylene carbonate; according to the GB / T14571.2-2018 standard, based on the chromatographic purity of the ethylene glycol, the chromatographic peak area of the inhibitor in the mixture of the ethylene glycol and the inhibitor is 0.05%-0.6% of the sum of the chromatographic peak area of the inhibitor and the chromatographic peak area of the ethylene glycol. The preparation method can effectively reduce the content of acetaldehyde in the polyethylene furandicarboxylate resin.

This application provides a secondary battery and a power consumption device. The secondary battery of this application comprises a negative electrode sheet and a non-aqueous electrolyte, the negative electrode sheet comprising a negative electrode active material having a volume average particle size Dv50 of 6 to 20 μm, the non-aqueous electrolyte comprising an additive and a non-aqueous solvent, the additive comprising a cyclic sulfate ester compound represented by formula (I), and the non-aqueous solvent comprising ethylene carbonate. Thus, this application forms a non-aqueous electrolyte using an ethylene carbonate solvent and an additive and combines it with a negative electrode active material of a certain particle size. JPEG2026518375000042.jpg4569

Lithium secondary battery, comprehensive a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte, wherein: the positive electrode comprises a positive electrode active material, wherein the positive electrode active material comprises lithium iron phosphate particles and the positive electrode has a loading amount of 450 mg / 25 cm² 2 up to 740 mg / 25 cm 2 exhibits; and the non-aqueous electrolyte comprises a lithium salt, an organic solvent and an additive, wherein the organic solvent comprises a solvent based on a cyclic carbonate and a solvent based on a linear carbonate, wherein the solvent based on a cyclic carbonate comprises ethylene carbonate and the solvent based on a linear carbonate comprises dimethyl carbonate, the additive comprises vinylene carbonate and the dimethyl carbonate is present in an amount of 5 vol% to 75 vol% in the organic solvent and the weight ratio of vinylene carbonate to dimethyl carbonate is greater than 0 to 0.2 or less.

The invention provides an electrolyte, a lithium iron manganese phosphate battery and an electric device. The electrolyte comprises a lithium salt and a solvent, the solvent comprises ethylene carbonate, propylene carbonate, ethyl methyl carbonate, fluorobenzene and a low-viscosity solvent in a volume ratio of (2-5): (2-5): (3-5): (3-5): (2-5). The high dielectric constants of ethylene carbonate and propylene carbonate improve the dissolving capacity of the electrolyte to lithium salt, and meanwhile, the molecular structure can form a stable interface layer on the surface of a positive electrode to inhibit migration and dissolution of manganese ions; due to the low viscosity characteristic of the low-viscosity solvent, the overall viscosity of the electrolyte is reduced, and the permeability of the porous positive electrode material is enhanced, so that the wettability is improved, and uniform de-intercalation of lithium ions is promoted; a physical adsorption protection layer can be formed on the surface of the positive electrode through the coordination effect of high-electronegativity fluorine atoms in fluorobenzene and manganese, and direct contact between manganese and electrolyte is further blocked.

The invention provides a preparation method of 2-acrylic acid 2-(2-naphthalenethio) ethyl ester, which comprises the following steps: (1) adding 2-thionaphthol, a first reactant and a catalyst into a first solvent, reacting at 110-140 DEG C for 4-10 hours, and washing with water to obtain 2-naphthyl sulfide ethanol; and (2) adding 2-naphthyl sulfide ethanol and a reaction aid into a second solvent, dropwise adding a second reactant, and reacting at 0-30 DEG C for 2-10 hours to obtain the 2-naphthyl sulfide ethanol, wherein the first reactant is 2-halogenated ethanol, ethylene oxide or ethylene carbonate and derivatives thereof; the second reactant is acryloyl chloride, alpha-methacryloyl chloride or a mixture of acrylic acid and phosphorus oxychloride. The preparation process is safe and simple, the cost is low, the reaction conditions are mild, the reaction polymerization can be effectively controlled, the post-treatment flow is simple, and industrialization is easy.

A method of easily obtaining a recycled carbon material by removing more Li from a carbon-based negative electrode active material containing Li is provided. A manufacturing method for a recycled carbon material according to the present disclosure includes: a first thermal process step of thermally processing a carbon-based negative electrode active material containing Li together with ethylene carbonate at a temperature less than a boiling point of ethylene carbonate to obtain a thermally processed object containing lithium ethylene dicarbonate; and a second thermal process step of thermally processing the thermally processed object at a temperature more than or equal to the boiling point of ethylene carbonate to convert lithium ethylene dicarbonate into lithium carbonate.

The application discloses polylactic acid polyol as well as a preparation method and application thereof, and the preparation method comprises the following steps: preparing an in-situ catalyst by heating reaction of a zinc salt, an organic ammonium salt and bis(ethylene carbonate) ether; the anion of the organic ammonium salt is selected from any one of bromide, chloride and iodide; and a lactide monomer is added to obtain polylactic acid polyol through a polymerization reaction. The polylactic acid polyol prepared by the application has a flexible chain segment, can provide better flexibility, and can be applied to preparation of polyurethane materials.

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 2-imidazolidinone and a catalyst used in the preparation method. The invention discloses a preparation method of a sulfonic acid functionalized ionic liquid catalyst. The preparation method comprises the following steps: (1) synthesis of a PMO carrier; (2) sulfonic acid functionalization: preparing a sulfonic acid functionalized material SMO-SO3H by using a PMO carrier; and (3) immobilizing and activating the ionic liquid to obtain the sulfonic acid functionalized ionic liquid catalyst (SMO-IL). The invention also discloses a method for efficiently and greenly preparing 2-imidazolidinone by taking ethylene carbonate and urea as raw materials under the action of the self-made catalyst.

An object of the present disclosure is to provide a nonaqueous electrolytic solution and a lithium ion secondary battery using same, the nonaqueous electrolytic solution having both excellent battery safety when used at a high temperature, an important feature for secondary batteries to be installed in modern vehicles such as electric vehicles, and having excellent battery characteristics. The nonaqueous electrolytic solution of the present disclosure is a nonaqueous electrolytic solution including an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous solvent containing from 80 to 100 vol % in total of at least one selected from ethylene carbonate, propylene carbonate, and γ-butyrolactone, and the nonaqueous electrolytic solution further including a trifluoroacetic acid ester having an alcohol group with a carbon chain length of from 6 to 8.

In order to overcome the problems of high recovery price, high energy consumption and low utilization rate of the existing kettle residue for the production of ethylene glycol by ethylene carbonate alcoholysis method, the application provides a kettle residue recovery method and device for the production of ethylene glycol by ethylene carbonate alcoholysis method, and the application provides a kettle residue recovery method for the production of ethylene glycol by ethylene carbonate, which comprises the following steps: under the conditions of temperature 150-250 DEG C and pressure 0.6-2 MPa, the ethylene glycol in the kettle residue produced by the preparation of ethylene glycol by ethylene carbonate alcoholysis method is converted into diethylene glycol under the catalysis of alkali metal salt catalyst, and after the reaction is completed, the kettle residue is a mixture of ethylene glycol, diethylene glycol, triethylene glycol and salt, the mixture is purified, and ethylene glycol and diethylene glycol are recovered; the economic benefit is improved, the rectification separation operation is simplified, the equipment investment and the overall energy consumption are reduced, and the utilization rate of ethylene glycol kettle residue is improved.

A non-aqueous electrolyte secondary battery has a negative electrode (12) having a negative electrode current collector (40) and a negative electrode compound layer (42) disposed on the surface of the negative electrode current collector (40). The negative electrode compound layer (42) contains a first negative electrode active material with a first internal porosity and a second negative electrode active material with a second internal porosity greater than the first internal porosity. The first negative electrode active material is largely contained on the surface side of the negative electrode compound layer (42). The non-aqueous electrolyte contains at least a sulfonyl lactone compound having unsaturated bonds and fluoroethylene carbonate. In the non-aqueous electrolyte, when the concentration of the sulfonyl lactone compound is set to X mass% and the concentration of fluoroethylene carbonate is set to Y mass%, the following conditions are met: 0.01≤X≤5.0, 0.01≤Y≤2.0, and X / Y>0.5.

A method of the present disclosure for producing an electrode active material sheet includes providing an electrode mixture comprising active material particles, a binder, and ethylene carbonate, and pressing the electrode mixture with a press member, wherein pressing the electrode mixture with the press member includes at least partially melting the ethylene carbonate.

This invention belongs to the field of solid-state electrolyte technology, specifically relating to a high-pressure resistant composite polymer solid-state electrolyte, its preparation method, and its application. The solid-state electrolyte comprises: a high-pressure resistant terpolymer, a PVDF-based polymer, mullite filler, and a lithium salt; the high-pressure resistant terpolymer is prepared from a high-pressure resistant additive, a crosslinking agent, ethylene ethylene carbonate monomer, and an initiator; the high-pressure resistant additive is selected from at least one of propylene-1,3-sulfonyl lactone, cyclobutene sulfone, and 3-methyl-3-cyclobutene sulfone. The preparation method is as follows: the high-pressure resistant additive, crosslinking agent, initiator, lithium salt, and ethylene ethylene carbonate monomer are mixed to obtain a precursor solution; the PVDF-based polymer and mullite filler are stirred and mixed in a solvent, coated into a film, and vacuum dried to obtain a base film; the base film is immersed in the precursor solution, and after immersion, it is cured to obtain the high-pressure resistant composite polymer solid-state electrolyte.

This invention relates to the field of chemical synthesis technology, specifically disclosing a method for preparing vinyl ethylene carbonate. The method uses glycidyl as a starting material, first converting it to glycidaldehyde via a mild oxidation reaction with high selectivity. Then, using a cross-linked imidazole polymeric ionic liquid as a catalyst, glycidaldehyde undergoes an atom-economical cycloaddition reaction with carbon dioxide to construct a cyclic carbonate intermediate. Finally, under catalytic conditions, a condensation reaction introduces a vinyl functional group to obtain the vinyl ethylene carbonate product. This invention uses widely available, low-toxicity, and inexpensive glycidyl instead of highly toxic raw materials, and utilizes greenhouse gas carbon dioxide as a carbonyl source for resource utilization. The process route is highly atom-economical, the reaction conditions are mild, and the catalyst is easy to separate, recover, and recycle, effectively solving the prominent problems of high raw material toxicity, expensive catalysts, and difficult byproduct treatment in traditional preparation techniques.

Lithium-ion battery, characterized in that it consists of a cathode, an anode and a non-aqueous electrolyte; wherein the cathode comprises a cathode material layer containing an active cathode material, wherein the active cathode material comprises a compound represented by formula (A): Li x Ni a Co b M' 1-a-b O 2-y A y Formula (A) where in formula (A) -0.1 ≤ x ≤ 0.2, 0.8 ≤ a < 1, 0 ≤ b < 0.2, 0.8 ≤ a + b < 1, 0 ≤ y < 0.2 hold; where M' comprises one or both of the elements Mn or Al and zero, one or more of the elements Sr, Mg, Ti, Ca, Zr, Zn, Si, Fe, B, Ga, Cr, W, V, Nb and Ce; where A comprises one or more of S, N, F, B, Cl, Br and I; wherein the anode comprises an anode material layer containing an active anode material, wherein the active anode material comprises a silicon-based material; wherein the non-aqueous electrolyte comprises a lithium salt and an organic solvent, wherein the organic solvent comprises cyclic carbonate, and wherein the cyclic carbonate comprises fluorinated ethylene carbonate and propylene carbonate; where the lithium-ion battery meets the following conditions: 0.2 ≤ S / F ≤ 2 ,0 ,2 ≤ P / F ≤ 3 ,5 and 3 ≤ S ≤ 15 ,2 ≤ F ≤ 15 ,2 ≤ P ≤ 25 , 15 ≤ C ≤ 40; where S denotes the mass fraction of silicon in the anode material layer, expressed in wt.%; where F denotes the mass fraction of fluorinated ethylene carbonate in the non-aqueous electrolyte, expressed in wt.%; where P denotes the mass fraction of propylene carbonate in the non-aqueous electrolyte, expressed in wt.%; where C denotes the mass fraction of cyclic carbonate in the non-aqueous electrolyte, expressed in wt.%.

The invention discloses a beta-ketimine type binuclear aluminum complex and a preparation method thereof. The binuclear aluminum complex can be used for catalyzing ring opening polymerization of caprolactone, lactide, glycolide, valerolactone, butyrolactone or ethylene carbonate. The invention further discloses a preparation method and application of the binuclear aluminum complex. The preparation method is simple, the reaction condition is mild, the prepared beta-ketimine type binuclear aluminum complex is used as a catalyst, the catalytic activity is high, the stability is good, the service life is long, the molecular weight distribution of the obtained polymerization product is narrow, and the beta-ketimine type binuclear aluminum complex can be well applied to the ring-opening polymerization reaction of cyclic ester.

This invention relates to the field of battery technology, specifically to a battery. The battery includes a positive electrode and an electrolyte. The positive electrode includes a positive current collector and a positive active layer. The positive active layer includes a ternary material, which comprises secondary particles interwoven from primary particles. The aspect ratio of the primary particles is 1.5-20. The ternary material has a hollow structure with internal cavities, and the area of ​​the cavities accounts for 5%-40% of the cross-section of the ternary material. The weight ratio of linear solvent to cyclic solvent in the electrolyte is 3-15. The cyclic solvent includes at least one of ethylene carbonate and propylene carbonate, and the weight percentage of the cyclic carbonate in the electrolyte is 8%-20%. The weight percentage of ethylene carbonate in the electrolyte is 0 < S1 ≤ 10%. The battery of this invention, through the synergistic effect of a specific ternary material structure and a specific electrolyte, enables the battery to possess both high low-temperature power performance and high cycle performance.

This invention relates to an electrolyte for lithium-ion batteries or lithium metal batteries, a method for preparing the electrolyte, and a lithium battery. The electrolyte comprises a lithium salt, an organic solvent, and functional additives, wherein the functional additives include aluminum alkoxide compounds. A battery containing the additives is also provided. Based on the discovery that ethylene carbonate (EC) degrades battery thermal safety under high-temperature thermal abuse conditions, aluminum isopropoxide is innovatively introduced as a functional additive. This additive is stable at room temperature, but under high-temperature thermal abuse scenarios, it can act as a Lewis acid catalyst, specifically catalyzing the ring-opening polymerization reaction of EC in the electrolyte to generate polymer segments. Compared with existing technologies, the electrolyte provided by this invention effectively improves the high-temperature storage performance and thermal shock resistance of the battery without sacrificing its room-temperature electrochemical performance.

The invention relates to a battery cell and a rechargeable lithium battery including the same. The battery cell includes: a wound electrode assembly including a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode; and an electrolyte immersed in the wound electrode assembly. The wound electrode assembly includes a pair of curved portions on opposite sides of the wound electrode assembly and a flat portion between the pair of curved portions. The electrolyte can include a non-aqueous organic solvent, a lithium salt, and an additive. The non-aqueous organic solvent comprises ethylene carbonate and ethyl propionate. The additive includes a compound represented by Chemical Formula 1. The ratio of the area of the negative electrode active material layer in the pair of curved portions to the total area of the negative electrode active material layer is 18%-50%. The volume ratio of the ethylene carbonate to the non-aqueous organic solvent is 20-50% by volume. The volume ratio of the ethyl propionate to the non-aqueous organic solvent is 50-80% by volume. Based on 100 parts by weight of the electrolyte, the amount of the additive is 1-10 parts by weight. Chemical formula 1

The utility model provides a horizontal condenser for producing ethylene carbonate, which relates to the technical field of horizontal condensers and comprises a condensing tank and an air inlet component, the air inlet component comprises an air inlet pipe fixedly connected onto the condensing tank, a flow shielding ring is fixedly connected inside the air inlet pipe, and a shielding opening is formed inside the flow shielding ring; the turbulent flow assembly comprises a front-side turbulent flow plate fixedly connected to the interior of the condensation tank, and a rear-side turbulent flow plate is fixedly connected to the end, away from the front-side turbulent flow plate, of the interior of the front-side turbulent flow plate; a liquid phase equilibrium assembly; according to the design, the conical shielding opening is matched with the spoiler, high-speed jet flow at an inlet is converted into low-speed uniform flow, local scouring and short circuit are avoided, the gas-liquid contact efficiency is improved, the turbulence degree is increased through the S-shaped flow channel, the liquid film thickness is reduced, the heat transfer coefficient is increased, and the condensation efficiency is remarkably improved. And finally, the liquid phase balance assembly ensures that the condensate is discharged in time through height difference drainage and pressure balance design, and heat exchange is prevented from being affected by accumulated liquid.

The invention discloses an electrochemical device and an electronic device, the electrochemical device comprises a positive pole piece, a negative pole piece and a non-aqueous electrolyte, the positive pole piece comprises a positive pole material layer, the negative pole piece comprises a negative pole material layer, and the negative pole material layer comprises a negative pole material; the positive electrode material layer comprises a nickel cobalt lithium manganate material and / or a nickel cobalt lithium aluminate material, the mass content of a nickel element in the positive electrode material layer is m%, and m is larger than or equal to 29 and smaller than or equal to 56.5; the negative electrode material comprises a silicon element, the mass content of the silicon element in the negative electrode material layer is e%, and e is larger than or equal to 3.5 and smaller than or equal to 60; the non-aqueous electrolyte comprises fluoroethylene carbonate and a compound shown in a formula I, based on the total mass of the non-aqueous electrolyte, the mass content of the compound shown in the formula I is a%, the mass content of fluoroethylene carbonate is b%, a is larger than or equal to 0.5 and smaller than or equal to 20, b is larger than or equal to 1 and smaller than or equal to 30, and a / b is larger than 0.2 and smaller than or equal to 4.

Provided are electrolytes suitable for use in secondary cells, optionally lithium-ion secondary cells wherein the electrolytes provide excellent cycle life optionally in NMC based lithium-ion cells that are initially formed with a charge cutoff voltage of >4.3 V and subsequently cycled with a charge cutoff of ≤4.65 V during cell operation. The electrolyte optionally excludes ethylene carbonate and / or additives toxic to humans at the concentration used in the electrolyte.