1333 results about "Methyl carbonate" patented technology

Desirable electrolyte compositions are described that are suitable for high voltage lithium ion batteries with a rated charge voltage at least about 4.45 volts. The electrolyte compositions can comprise ethylene carbonate and solvent composition selected from the group consisting of dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, γ-valerolactone or a combination thereof. The electrolyte can further comprise a stabilization additive. The electrolytes can be effectively used with lithium rich positive electrode active materials.

The invention discloses various embodiments of Li-ion electrolytes containing flame retardant additives that have delivered good performance over a wide temperature range, good cycle life characteristics, and improved safety characteristics, namely, reduced flammability. In one embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a fluorinated co-solvent, a flame retardant additive, and a lithium salt. In another embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a flame retardant additive, a solid electrolyte interface (SEI) film forming agent, and a lithium salt.

The invention relates to a non-aqueous electrolyte for high-voltage lithium ion batteries, which is prepared from the following raw materials in percentage by weight: 70-85% of carbonate, 3-20% of functional additive and 11-17% of lithium hexafluorophosphate. The carbonate is one or mixture of more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylethyl carbonate, methyl propyl carbonate and methyl butyl carbonate; and the functional additive is one or mixture of more of 0.5-10% of negative pole film-forming additive, 0.5-10% of high-temperature additive, 0.5-10% of positive pole film-forming additive, 0.5-10% of high-voltage additive and 0.001-2% of stability additive. The invention solves the problem of adaptation of the lithium ion battery electrolyte to the 4.35V high-voltage battery positive/negative pole, and provides an electrolyte for high-voltage batteries, which has the advantages of high cycle life, low inflation rate and favorable high-temperature properties.

The invention discloses a lithium-ion secondary battery and an electrolyte thereof. The electrolyte comprises a solvent, lithium salt and a film forming additive, wherein the solvent comprises a first solvent and a second solvent; the first solvent comprises linear carboxylic ester and ethylene carbonate; the second solvent is one or more of ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate and propylene carbonate; and the film forming additive is one or more of fluoroethylene carbonate, vinylene carbonate, 1,3-propane suhone, succinonitrile, adiponitrile, lithium bis(oxalato)borate, and lithium oxalyldifluoroborate. Due to the collocation of linear carboxylic ester and ethylene carbonate, a solvent system with a higher dielectric constant and low viscosity is obtained; the film forming additive improves poor compatibility between linear carboxylic ester and graphite; and finally the lithium-ion secondary battery adopting the electrolyte presents high-power discharge capacity, excellent high-temperature cycling stability and low-temperature charge and discharge properties.

A secondary battery is comprised of a positive electrode, a negative electrode formed from a lithium storage material, and a non-aqueous electrolyte. The non-aqueous electrolyte includes a lithium salt, non-aqueous aprotic solvent(s), such as ethylen carbonate, propylene carbonate, dimethyl carbonate, ethymethyl carbonate and diethyl carbonate, and a small percentage of at least one organic additive. The negative electrode may comprise a carbon such as graphite, and the positive electrode may comprise a lithiated metal oxide or phosphate, such as LiCoO₂, LiNiO₂, LiMn₂O₄, LiFePO₄, or mixtures thereof. The organic additives have one or more unsaturated bonds activated with respect to oxidation by electron-pushing alkyl groups. They are in most cases known to be able to undergo polymerization reactions, such as an anodically induced polymerization especially under certain conditions. The additives are oxidized at the cathode at a potential of more than 4.3 V vs. Li/Li⁺. With these additives in amounts of 0.001 to 10%, a passivation layer is formed on the cathodes, and the sensitiveness of the battery against overcharge is reduced. The electrolyte mixtures do not deteriorate the properties of the battery anodes.

The invention discloses various embodiments of electrolytes for use in lithium-ion batteries, the electrolytes having improved safety and the ability to operate with high capacity anodes and high voltage cathodes. In one embodiment there is provided an electrolyte for use in a lithium-ion battery comprising an anode and a high voltage cathode. The electrolyte has a mixture of a cyclic carbonate of ethylene carbonate (EC) or mono-fluoroethylene carbonate (FEC) co-solvent, ethyl methyl carbonate (EMC), a flame retardant additive, a lithium salt, and an electrolyte additive that improves compatibility and performance of the lithium-ion battery with a high voltage cathode. The lithium-ion battery is charged to a voltage in a range of from about 2.0 V (Volts) to about 5.0 V (Volts).

The invention discloses a lithium-ion battery with fast charge property, which comprises an anode, a cathode, a diaphragm sandwiched between the anode and the cathode and an organic electrolyte, wherein, sub micrometer lithium titanate is used as the active substance of the cathode; one or several materials of lithium manganate (LiMn2O4), lithium iron phosphate (LiFePO4), lithium nickel cobalt oxide (LiNixCoyMzO2), ternary substance(LiNixMnxCo1-2xO2) are used as active materials of the anode, or a mixture of lithium cobalt (LiCoO2) and one of lithium manganate (LiMn2O4), lithium iron phosphate (LiFePO4), lithium nickel cobalt oxide (LiNixCoyMzO2), ternary substance(LiNixMnxCo1-2xO2) is adopted as the active materials of the anode; lithium hexafluorophosphate (LiPF6) is adopted as the electrolyte, and a multicomponent mixture of ethylene carbonate (EC), dimethylcarbonate(DMC), Ethyl Methyl Carbonate (EMC) is used as a solution. The invention also discloses a preparation method of the lithium-ion battery with fast charged property. The lithium-ion battery of the invention has excellent fast charging and discharging performance.

There is provided in one embodiment of the invention an electrolyte for use in a lithium ion electrochemical cell. The electrolyte comprises a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), an ester cosolvent, and a lithium salt. The ester cosolvent comprises methyl propionate (MP), ethyl propionate (EP), methyl butyrate (MB), ethyl butyrate (EB), propyl butyrate (PB), or butyl butyrate (BB). The electrochemical cell operates in a temperature range of from about −60 degrees Celsius to about 60 degrees Celsius. In another embodiment there is provided a lithium ion electrochemical cell using the electrolyte of the invention.

The utility model relates to a method which utilizes a vapour permeation membrane to separate dimethyl carbonate from methanol azeotrope. Saturated vapour at the temperature of 64 to 120 DEG C and with the pressure of 0.10 to 0.6 MPa is sent into a membrane separator and is contacted with a separation membrane, the downstream side of the membrane separator keeps the vacuum degree at 4 to 200 mmHg by vacuum pumping, the dimethyl carbonate first passes through a concentration membrance filter at the permeation side of the membrane and is condensed into liquid under the condition of vacuum and low pressure, the liquid mixture directly enters into an atmospheric rectifying column, dimethyl carbonate with more than or equal to ninety nine point five percent of content is produced from the bottom of the column, and high-concentration methanol is produced from the interception side of the membrane separator and enters into next technique unit. The separation membrane is an organic composite membrane, an organic and mineral composite membrane or a mineral membrane which can preferentially permeate dimethyl carbonate, and the method has the advantages of simple technique and low energy consumption; the throughput of the permeation of the membrane is increased, and the area of the membrane is reduced; safety and reliability are increased, and the purity of dimethyl carbonate is increased as well.

The method for synthesizing dimethyl carbonate by using urea and methanol and adopting heterogeneous catalyst includes the following steps: under the condition of 600-1300 deg.c 10X10 to the power 5-1X10 to the power 5 pa and air or oxygen gas atmosphere calcining carbonate or hydroxide of alkali metal and alkaline earth metal for 1-10 hr. to obtain catalyst, adding urea and methanol into high-pressure reaction still, and adding catalyst, heating to 120-180 deg.c under the condition of magnetic stirring, low-temp. resistion time is 2 hr-10 hr. more heating to 180-240 deg.C, high-temp. reaction time 2 hr-20 hr, cooling to room temp. and making separation so as to obtain the invented roduct.

The invention relates to a preparation method of methyl ethyl carbonate, which takes methyl carbonate and ethanol as raw material and carries on transesterification with the existence of the catalyst with the reaction temperature of 50 DEG C to 60 DEG C. The temperature of the reaction materials rises from room temperature with a heating rate of five to ten DEG C per hour. The method also includes a water removing treatment to the ethanol so that the water content of the ethanol is less than or equal to 0.1 percent of the gross weight of the ethanol. By adopting the preparation method of the invention, the purity of the methyl ethyl carbonate is as high as 99.8 percent and the yield is higher than 70 percent. The method has the advantages of mild reaction condition, simple separation and purification of reaction products and low cost.

The invention discloses a two-metal composite oxide catalyst of synthetic biphenyl carbonate through ester exchange, which consists of vanadium oxide and copper oxide, wherein the mole ratio is that V:Cuú¢100í†1-100; The sintering temperature is between 250 and 850 deg C; the parent body can be vanadium salt or vanadium oxide and copper salt or copper oxide; the making method adapts coprecipitation method or mechanic abrasion method. The invention improves the total productivity of biphenyl carbonate, which is easy to separate and recover the biphenyl carbonate.

The invention relates to the technical field of a secondary power (a chargeable battery) which can be reused, in particular to a 26650 type lithium ion battery which is safe and has high capacity and a preparation method thereof. Lithium ferrous phosphate is used as cathode material; graphite materials are adopted as anode materials; mixture of EC (ethylene carbonate), DMC (Di Methyl Carbonate), EMC (methyl ethyl carbonate) (based on volume ratio of 1: 1: 1) is used as electrolyte solution, and LiPF6 (lithium hexafluorophosphate ) with molar ration 1.0 to 1.4 mol/L is adopted as electrolyte; multi-porous PP (polypropylene) and PE (polyethylene) are used as separating membrane, and a metal tank is used as a shell, thus the 26650 type battery is made with the diameter of 26mm and the height of 65mm; the capacity of the battery can reach 3200mAh, the internal resistance is within 30mOmega, and the cycle life thereof is more than 1000 times. The 26650 type lithium ion battery mainly solves the limitation problem of the existing lithium ion battery in the respect of safe and large size, and develops towards large size, has longer service life and higher safety and belongs to an environment protection chemical power with wider application.

The invention relates to a method for synthesizing methylethyl carbonate. According to the method, under ordinary pressure, dimethyl carbonate and ethanol which are used as raw materials are subjected to synthetic reaction of methylethyl carbonate at certain reaction temperature for some time by using an imidazole ionic liquid as a catalyst. The invention has the following advantages: the catalyst consumption is only 0.5-5 wt% of the dimethyl carbonate; the ionic liquid catalyst has high catalytic activity in the reaction process, the maximum yield of methylethyl carbonate is up to 71.22%, and the selectivity is up to 88.52%; and the catalyst can be recycled for cyclic utilization after being subjected to simple treatment after reaction, has the advantages of long service life and no pollution, and greatly lowers the preparation cost of methylethyl carbonate.

The invention discloses a method of distillation and ester exchange reaction for producing dimethyl carbonate and dihydroxyl alcohols comprising the following steps, counterflow contacting cyclic carbonates absorbent with mixed gas containing alkylene oxide and carbon dioxide in an absorption column, reacting alkylene oxide with carbon dioxide to obtain cyclic carbonate, the cyclic carbonate synthesized liquid entering a rectifying tower, the cyclic carbonate on top of the tower entering an reaction rectifying tower through pipe lines, carrying out ester exchange reaction with menthol at the presence of ester exchange catalyst, obtaining dimethyl carbonate and dibastic alcohol.

The invention discloses a process for synthesizing methyl carbonate by alcoholysis of urea with aliphatic diol as cyclic agent consisting two steps, (1) reacting urea with aliphatic diatomic alcohol (ethylene glycol or 1,2-methyl ethylene glycol) to synthesize ethylene carbonate ester or propylene carbonate ester, (2) subjecting ethylene carbonate ester or propylene carbonate ester with methanol ester to synthesize methylcarbonate.

The invention discloses a process for synthesizing methyl carbonate from alcoholysis of methanol and urea in a high pressure reactor, wherein the catalyst is a amine salt type ionic liquid having a molecular formula of R1R2R3NHX-MaXb, the raw material methanol and urea are subject to alcoholysis reaction and methyl carbonate is synthesized in one step.

A gasifying osmotic film for separating the azeotropic methanol/dimethyl carbonate solution is prepared from polyvinyl alcohol and polyacrylic acid. Its preparing process is also disclosed.

The invention discloses a preparation method for a double metal cyanide catalyst for polycarbonate synthesis. The preparation method comprises the following steps of: firstly dissolving soluble metallic salt in organic ligand, and then adding deionized water to serve as a solution 1; dissolving water-soluble metallic cyanide salt in the deionized water to serve as a solution 2, wherein the volume ratio of the solution 1 to the solution 2 is 0.1: 1-5: 1; and then dripping the solution 2 to the solution 1 to obtain a solid catalyst after stirring and drying. In the invention, the influence of the deionized water to the synergic action between the organic ligand and the soluble metal salt is avoided; the synergic action between the organic ligand and the soluble metal salt in the DMC (Di Methyl Carbonate) catalyst is exerted at the greatest degree; and the reaction time when the catalyst catalyzes a copolymerization of propylene oxide and CO2 does not exceed 8h, the activity reaches to above 30Kg polymer/g catalyst, and the CO2 unit content in the polymer reaches up to 45.0%.

Electrolytes, lithium ion cells and corresponding methods are provided, for extending the cycle life of fast charging lithium ion batteries. The electrolytes are based on fluoroethylene carbonate (FEC) and/or vinylene carbonate (VC) as the cyclic carbonate component, and possibly on ethyl acetate (EA) and/or ethyl methyl carbonate (EMC) as the linear component. Proposed electrolytes extend the cycle life by factors of two or more, as indicated by several complementary measurements.

In this invention, fatly acid and ethanolamine are proportioned and under ester-aminated, then reacting with dimethyl carbonate to produce ester-amine type quaternary ammonium salt. Said invention p rocess of synthesis has high transforming rate, excellent selectivity, high content of active matter in said product, utilizing no pollution type raw material of dimethyl carbonate, so, no remaining of poison in product, lowering quaternary ammonium salt pollution to environment and to human health.