160results about How to "Improve high temperature storage performance" patented technology

The invention discloses a carbon-silicon negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: S1, carrying out mixed reaction on a lithium source compound, a lanthanum source compound and a titanium source compound to obtain a mixed reactant; mixing the mixed reactant with a carbon source compound, and dispersing and emulsifying to obtain element-doped microspheres; s2, carbonizing the element-doped microspheres in the step S1 to obtain carbides, and activating the carbides to obtain a porous carbon material; and S3, performing silicon deposition on the porous carbon material in the S2 to obtain silicon deposition porous carbon, and performing carbon deposition on the silicon deposition porous carbon to obtain the carbon-silicon negative electrode material. The carbon-silicon negative electrode material disclosed by the invention is high in lithium ion transmission rate, the problem of poor electronic conductivity of silicon is solved, and the electrical property of a battery can be effectively improved.

The invention relates to a lithium battery, a lithium battery negative plate and a preparation method of the lithium battery negative plate. The preparation method of the lithium battery negative electrode plate comprises the steps that a current collector is coated with negative electrode slurry, after drying, three times of rolling is conducted in sequence, the negative electrode plate is obtained, the thickness after first-time rolling is H1, the thickness after second-time rolling is H2, the target thickness of the negative electrode plate is H3, H3 / H1 = A1, H3 / H2 = A2, A1 is 60%-90%, and the difference value between A2 and A1 is 5%-30%. According to the preparation method of the negative electrode plate provided by the invention, through three times of rolling treatment with a specific compression roller ratio, the rolling treatment uniformity of the negative electrode plate is improved, active substances in the negative electrode plate are prevented from being broken and pulverized, the stability of a solid electrolyte interface film is effectively improved, the rebound rate of the negative electrode plate can be effectively reduced, and the service life of the negative electrode plate is prolonged. And the compaction density and thickness of the negative plate are ensured, so that the high-temperature storage performance of the lithium battery is improved.

In order to solve the problem that an existing lithium ion battery is insufficient in rate performance, high-temperature performance and low-temperature performance, the invention provides a lithium ion battery which comprises a positive electrode, a negative electrode and a non-aqueous electrolyte, the negative electrode comprises a negative electrode material layer containing a negative electrode active material and a negative electrode interface film formed on the surface of the negative electrode material layer, and the non-aqueous electrolyte is formed on the surface of the negative electrode material layer. The specific surface area of the negative electrode material layer is 0.5-5 m < 2 > / g, the median particle size of the negative electrode material layer is 8-17 [mu] m, the non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, the additive comprises a lithium salt type additive and a compound represented by a structural formula 1: # imgabs0, and the lithium ion battery satisfies the following condition: 0.5 < = Wa / Wb < = 10. According to the lithium ion battery provided by the invention, the proportion of the organic matter component and the inorganic matter component in the negative electrode interface film is mutually coordinated, so that a lithium ion interface transmission channel can be optimized, and the high-temperature storage performance is optimal while the low-temperature performance and the rate capability are improved.

The invention relates to the technical field of electrochemistry, and particularly discloses a secondary battery and an electric device. A positive active material in the positive pole piece comprises a lithium manganese iron phosphate material; carrying out charge-discharge test on the secondary battery adopting the positive pole piece at 45 DEG C under the condition of 1C / 1C, and drawing a dQ / dV-V diagram; in a dQ / dV-V diagram, in a range of 3.0 V to 3.85 V, a main reduction peak at a lower potential is a peak A, and a main reduction peak at a higher potential is a peak B; the peak position difference value V of the peak A and the peak B and the half-peak width W of the peak A meet the following relational expression: V0.2 * W is greater than or equal to 0.011 and less than or equal to 0.145. According to the invention, the redox reaction characteristic of the positive electrode active material is controlled, so that the secondary battery containing the positive electrode active material has excellent high-temperature cycle characteristic and high-temperature storage performance.

The invention provides an electrolyte, an electrochemical device and an electronic device, the electrolyte comprises lithium difluorophosphate, a dinitrile compound and diethyl carbonate, based on the total mass of the electrolyte, the mass percentage content of the dinitrile compound is A%, the mass percentage content of the diethyl carbonate is B%, 10 < = A + B < = 24, and 0.8 < = A < = 3. The electrolyte comprising the lithium difluorophosphate, the dinitrile compound and the diethyl carbonate is adopted, the value of A + B is regulated and controlled, and the value of A is within the range, so that the high-temperature storage performance, the high-temperature cycle performance, the low-temperature discharge performance and the safety performance of the electrochemical device can be improved.

The invention relates to the technical field of lithium ion batteries, and particularly provides a preparation method of a graphite negative electrode material and the graphite negative electrode material. The problems that an existing method for improving the rate capability of a graphite negative electrode is complex in process and limited in improving effect, and high-temperature storage performance is deteriorated are solved. Therefore, the preparation method of the graphite negative electrode material comprises the following steps: S1, mixing aromatic hydrocarbon oil, thiophene and medium-high sulfur asphalt, and performing heat treatment to obtain vulcanized asphalt; s2, carrying out delayed coking on the vulcanized asphalt to obtain high-sulfur green coke; and S3, crushing the high-sulfur green coke, and then carrying out graphitization treatment to obtain the graphite negative electrode material. The graphite negative electrode material prepared by the preparation method provided by the invention has good rate capability and high-temperature storage performance.

The invention provides a non-aqueous electrolyte and a lithium ion battery thereof. The non-aqueous electrolyte comprises a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive comprises a compound A as shown in a formula I and a compound B as shown in a formula II. Wherein R1, R2, R3 and R4 are respectively and independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl and substituted or unsubstituted C2-C12 alkynyl, n is a natural number from 1 to 5, and M is alkali metal. The non-aqueous electrolyte provided by the invention contains two additives, namely the compound A and the compound B, and through the synergistic effect of the two additives, the increase of high-temperature storage internal resistance can be reduced, and the high-temperature storage performance of the lithium ion battery can be improved. # imgabs0 #

The invention discloses a formation method of a semi-solid-state lithium battery and the semi-solid-state lithium battery, and relates to the technical field of lithium ion batteries. The formation process is divided into a low-current charging stage, an oscillation circulation stage and a pressurization polymerization stage, low-current oscillation circulation is performed in an SOC interval with the fastest expansion rate of negative electrode graphite, so that sufficient and uniform huff and puff and film formation of an electrolyte are realized in a battery cell, and the film formation integrity and the electrolyte infiltration degree of the battery cell are improved; according to the present invention, the pressure is set at the SOC position with the maximum expansion degree of the negative electrode graphite, and the pressurization is combined with the highest expansion time of the negative electrode graphite, such that the adhesion of the electrolyte to the interior and the surface layer of the pole piece pore during the in-situ polymerization process is well achieved so as to significantly improve the in-situ curing effect, such that the dispersion degree of the battery capacity is centralized. According to the semi-solid gel electrolyte formed by the formation method provided by the invention, the transmission path of Mn < 2 + > in the electrolyte is well hindered, and the high-temperature storage performance of the battery is improved.

The invention provides a positive electrode material, an electrochemical device and an electronic device. The section of a positive electrode material particle comprises a first region and a second region; wherein the middle point of the longest diameter in the cross section is taken as a center, a connecting line from the center to any point on the surface of the positive electrode material particle in the cross section is taken as a first connecting line, the first connecting line is provided with a first demarcation point, and the distance from the center to the first demarcation point is 3 / 5 of the length of the first connecting line where the first demarcation point is located; the first area is an area enclosed by the first demarcation point; the second area is an area except the first area in the cross section; the void ratio of the first area is Vc1, the void ratio of the second area is Vc2, and Vc2-Vc1 is larger than or equal to 5% and smaller than or equal to 30%. The positive electrode material can improve the cycle performance and high-temperature storage performance of an electrochemical device.

The invention discloses a multiplying power type electrolyte additive, electrolyte and a lithium ion battery, and belongs to the technical field of lithium ion, the multiplying power type electrolyte additive is a silane group dimethyl ether compound containing two symmetrical structures, and the general formula of the additive is # imgabs0 #; the lithium ion battery comprises a positive plate, a negative plate, an isolating membrane and the multiplying power type electrolyte. According to the invention, the dimethyl ether compound of the methoxy silane group with a symmetrical structure is used as an additive to be applied to the preparation of the lithium ion battery electrolyte. According to the present invention, the dimethyl ether compound containing the methoxy silane group with the symmetric structure is combined with the auxiliary additive so as to provide characteristics of low cell impedance, excellent battery charge-discharge and cycle performance, and high temperature performance of the cell in the high energy density battery system; the electrolyte is used for manufacturing the lithium ion battery, and the obtained battery has excellent charge-discharge performance.

The invention provides an electrolyte, a preparation method thereof and a lithium ion battery, the electrolyte comprises an organic solvent, an additive and a lithium salt, and the additive comprises an additive A. The additive A is added into the electrolyte, and the imidazole group in the additive A enables the additive A to participate in positive electrode film formation and negative electrode film formation, so that the stability of a solid electrolyte interface film is improved; in addition, the additive A can be used as a Lewis base to capture H2O and corrosive substances such as phosphorus pentafluoride and hydrofluoric acid in the battery, so that side reactions between water, gas and the corrosive substances and other components in the battery are reduced; in addition, the cyano group, the cyanoethyl group or the dimethylene cyano group and other groups in the additive A can be used as Lewis base to adsorb hydrofluoric acid. And the additive A can improve the stability of interface films of the positive and negative solid electrolytes and reduce side reactions between water, gas and corrosive substances and other components in the battery, so that the high-temperature storage performance and the cycle performance of the battery are improved.

The invention discloses an electrolyte and a lithium battery, and additives of the electrolyte comprise a compound as shown in a structural formula 1, a cyclic sulfate compound and a sultone compound, the proportions of the compound as shown in the structural formula 1, the cyclic sulfate compound and the sultone compound in the electrolyte are awt%, bwt% and cwt% respectively, 2.5 b-a is more than or equal to-0.5 and less than or equal to 4, and 2a + c is more than or equal to 5 and less than or equal to 8. In the design, the compound shown in the structural formula 1 can form stable interfacial films on the surfaces of the positive electrode and the negative electrode, oxidative decomposition of an electrolyte at high temperature is reduced, consumption of the electrolyte is inhibited, the high-temperature cycle performance is improved, and the cyclic sulfate compound can reduce film-forming impedance and improve gram volume exertion; the sultone compound can improve the high-temperature storage performance. Therefore, the high-temperature cycle and high-temperature nesting performance of the lithium battery is effectively improved by adjusting the ratio of the compound shown in the structural formula 1, the cyclic sulfate compound and the sultone compound.

The invention relates to the field of batteries, in particular to an electrolyte and an electrochemical device. The electrolyte comprises an organic solvent, an electrolyte and an electrolyte additive, and the electrolyte additive comprises a nitrile additive A and a nitrile additive B; the nitrile additive A comprises at least one of acetonitrile or butanedinitrile; the nitrile additive B comprises at least one of compounds shown as a formula I, # imgabs0, and R1 and R2 are independently and optionally selected from hydrogen, a straight chain or branched chain cyano group with the carbon atom number of 1-10, a straight chain or branched chain alkoxy group with the carbon atom number of 1-10, and a straight chain or branched chain halogenated hydrocarbon with the carbon atom number of 1-5. By combining the nitrile additive A and the nitrile additive B, the high-temperature storage performance and the cycle performance of the battery can be effectively improved at the same time.

The invention provides a non-aqueous electrolyte and a secondary battery containing the non-aqueous electrolyte. The non-aqueous electrolyte comprises an electrolyte salt, a non-aqueous organic solvent and an additive. The additive comprises a sulfonyl pyridinium inner salt compound and a sulfonyl fluoride compound. The structural formula of the sulfonyl pyridinium inner salt compound is as shown in the structural formula I. The structural formula of the fluorosulfonyl compound is shown as a structural formula II or a structural formula III. Wherein R < 1 > to R < 6 > are independently selected from hydrogen atoms and substituted or unsubstituted alkyl groups of C1 to C3, R < 7 > to R < 8 > are independently selected from hydrogen atoms and substituted or unsubstituted alkyl groups of C1 to C3, and R < 9 > is selected from alkylene groups of C1 to C10. The additive of the non-aqueous electrolyte contains a sulfonyl pyridinium inner salt compound and a sulfonyl fluoride compound, so that the high-temperature cycle performance can be improved while the high-temperature storage performance of the battery is improved. # imgabs0 #

The invention relates to a lithium ion battery and electronic equipment. The lithium ion battery comprises a positive plate and an electrolyte, the positive plate comprises a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector, and the positive active material layer comprises a positive additive; the electrolyte comprises a sulfur-containing additive and 1, 3-propane sultone, (X + Y) / (W * A) > = 0.025; wherein the mass percentage content of the sulfur-containing additive in the electrolyte is X%; the mass percentage content of the 1, 3-propane sultone in the electrolyte is Y%; the mass percentage content of the positive electrode additive in the positive electrode active material layer is W%; the specific surface area of the positive electrode additive is A m < 2 > / g. According to the scheme provided by the invention, the lithium ion battery can present excellent first coulombic efficiency, high-temperature cycle performance, high-temperature storage performance and low-temperature cycle performance.

The invention provides a positive electrode material and a preparation method thereof, a positive electrode plate and a secondary battery. The length-diameter ratio X / Y of particles in the positive electrode material meets the condition that X / Y is larger than or equal to 1 and smaller than or equal to 1.6, X is the length of the longest straight line side of a single particle, and Y is the length of a straight line side perpendicular to the midpoint position of the longest straight line side; and compacting under the pressure of 6T, and counting by a Malvern 3000 particle size tester that the volume ratio of particles with the particle size of less than 1 mu m in the positive electrode material is 2-4%. By controlling the length-diameter ratio and the micro powder content of the particles in the positive electrode material, the long-term cycle performance, the high-temperature storage performance and the gas production performance of the battery are improved, and meanwhile, the good capacity of the battery is ensured.

The invention provides an electrolyte additive. According to the high-voltage electrolyte for the high-nickel lithium ion battery, the problem of electrolyte deterioration caused by easy hydrolysis of phenylboronic acid functional groups is improved by introducing silicon-oxygen bonds, the application of the high-voltage electrolyte in battery circulation is expanded, the reaction of water or hydrofluoric acid and boron in the electrolyte is isolated through the large steric-hindrance effect of the silicon-oxygen groups, boron-oxygen bonds are reserved, and the service life of the high-voltage electrolyte is prolonged. Forming a uniform and thin inorganic boron-containing low-impedance CEI layer on the surface of the positive electrode; meanwhile, the trifluoromethanesulfonyl group can improve the high-temperature storage performance of the battery, and the additive is added into the non-aqueous organic solvent as a functional additive, so that the electrolyte has relatively high high-pressure resistance, oxidation resistance and high-temperature resistance, and the lithium ion battery containing the electrolyte has relatively good cycle performance at high pressure and high temperature.

This invention provides an electrolyte, a battery, a battery pack, and an electrical device. The electrolyte includes additives, including fluorocarbonate, unsaturated carbonate, a first sulfide additive, a second sulfide additive, and an anhydride additive. The first sulfide additive includes sulfonate compounds; the second sulfide additive includes sulfite compounds and / or sulfate compounds. Based on the mass of the electrolyte, the mass percentage of each component is as follows: fluorocarbonate m1%, 1.5≤m1≤5; unsaturated carbonate m2%, 1.5≤m2≤3; first sulfide additive m3%, 0.5≤m3≤2; second sulfide additive m4%, 0.5≤m4≤2; anhydride additive m5%, 0.3≤m5≤0.8; and satisfies 1≤(m1+m2) / (m3+m4+m5)≤3. This invention can effectively suppress gas generation at high temperatures in the battery and improve the cycle performance and storage performance of the battery under high-temperature conditions.

The present application provides an electrochemical device and an electronic device. The electrochemical device includes a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte includes a first additive and a second additive: the first additive includes at least one of the compound shown in Formula I and the compound shown in Formula II: the second additive includes a polynitrile compound shown in Formula III: wherein M1 and M2 are independently selected from halogen, Formula IV, and Formula V; wherein α and γ are independently selected from 0 or 1, and β is independently selected from 0, 1, and 2. The electrolyte is suitable for use in an electrochemical device, and can effectively improve the cycle stability and high-temperature storage performance of the electrochemical device, and enhance safety performance.

The invention provides a non-aqueous electrolyte and a secondary battery, the non-aqueous electrolyte comprises a non-aqueous organic solvent, an electrolyte salt and an additive, the non-aqueous organic solvent comprises ethylene carbonate, the additive comprises a first additive and a second additive, the first additive comprises a compound represented by a structural formula 1, and the second additive comprises a compound represented by a structural formula 2. The second additive comprises one or two of acetone and tert-butyl alcohol; the non-aqueous electrolyte satisfies the following conditions: a / c is greater than or equal to 1 and less than or equal to 100, # imgabs 1 # is greater than or equal to 0.1 and less than or equal to 2.5, a is greater than or equal to 0.001 and less than or equal to 1, and c is greater than or equal to 0.001 and less than or equal to 0.03; wherein a is the mass percentage content of the first additive in the non-aqueous electrolyte, and the unit is%; and c is the mass percentage content of the second additive in the non-aqueous electrolyte, and the unit is%. The lithium ion battery prepared from the non-aqueous electrolyte provided by the invention has relatively high cycle capacity retention ratio and high-temperature storage performance.

The application provides an electrolyte and a battery comprising the electrolyte, wherein the diazonium salt compound in the electrolyte can be decomposed in advance to generate a large amount of inert gas before a large amount of organic solvent is volatilized to generate gas during a furnace temperature test, and the inert gas is discharged from the pole lug, so that the generated heat is timely released, heat accumulation in the interior is avoided, and heat runaway is avoided; on the other hand, the volatilization of the organic solvent can cause the ion channel in the battery to be closed, so that the side reaction is stopped, the battery can safely pass the furnace temperature test, and the safety of the battery under the condition of heat runaway is significantly improved. Meanwhile, the electron-deficient B element in the diazonium salt compound in the electrolyte has Lewis acidity, can accept an electron pair, can remove HF in the electrolyte, avoids the damage of HF to the interface protection film, and further improves the high-temperature storage performance of the battery.

To overcome the problem of insufficient high-temperature cycle performance in existing lithium-ion batteries, this invention provides a lithium-ion battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode includes a positive electrode current collector with a conductive coating on its surface and a positive electrode material layer disposed on the positive electrode current collector. The non-aqueous electrolyte includes a non-aqueous organic solvent, a lithium salt, and an additive. The additive includes a compound represented by structural formula 1. The lithium-ion battery satisfies the following condition: and 2.4 ≤ M. A ≤3.6, 0.1≤W A ≤5, 0.1≤d≤10, 3.3≤c≤3.8. The lithium-ion battery provided by this invention can effectively improve high-temperature cycling and storage performance.

The invention provides an electrolyte, a secondary battery and a device. The electrolyte comprises a lithium salt, a solvent and an additive, wherein the additive comprises an unsaturated cyclic carbonate additive and a sulfonate additive; the unsaturated cyclic carbonate additive comprises at least one of compounds shown in a formula I, the sulfonate additive comprises at least one of compounds shown in a formula II-A and a formula II-B, the mass percentage content of the unsaturated cyclic carbonate additive is P1% based on the total mass of the electrolyte, and P1 is larger than or equal to 0.01 and smaller than or equal to 10. According to the electrolyte, a layer of special CEI interface film can be formed on the surface of the positive electrode active material, so that the electrochemical performance of the positive electrode active material is improved.

The present invention discloses a rate-type electrolyte additive, an electrolyte and a lithium-ion battery, which belong to the field of lithium-ion technology. The rate-type electrolyte additive is a dimethyl ether compound containing two symmetrically structured silane groups, and the general formula of the additive is:; The lithium-ion battery comprises a positive electrode sheet, a negative electrode sheet, a separator and the above-mentioned rate-type electrolyte. The present invention uses a dimethyl ether compound of a symmetrically structured methoxysilane group as an additive to manufacture a lithium-ion battery electrolyte. The dimethyl ether compound containing a symmetrically structured methoxysilane group is used in combination with an auxiliary additive, and in a high-energy-density battery system, it has lower cell impedance, better battery charge-discharge and cycle performance, and can also take into account the high-temperature performance of the cell. The electrolyte is used to manufacture a lithium-ion battery, and the resulting battery has excellent charge-discharge performance.

The invention relates to the technical field of batteries, in particular to a negative plate and a battery. The negative plate comprises a negative current collector and a negative active coating positioned on at least one side surface of the negative current collector, and the negative active coating comprises silicon-based particles; the number of the silicon-based particles in a 100 [mu] m * 100 [mu] m area on the surface of the negative electrode active coating is a, and a is greater than or equal to 1 and less than or The average sphericity of the silicon-based particles is b, and b is more than or equal to 0.66 and less than or equal to 1; a and b satisfy 1 < = a / b < = 67, the self-discharge degree of the battery can be reduced, and the high-temperature storage performance of the battery can be improved.

The invention discloses a lithium manganate battery and a preparation method thereof. The lithium manganate battery comprises a positive plate, a diaphragm, a negative plate and a functional diaphragm, the functional diaphragm comprises CaO2 and a multi-dimensional conductive carbon material; the functional diaphragm is arranged between the positive plate and the diaphragm, and / or the functional diaphragm is arranged between the negative plate and the diaphragm, HF in an electrolyte is consumed through alkaline compounds in the functional diaphragm, dissolution of manganese in the positive electrode is reduced, but interface impedance can be increased through an interface layer composed of the independent alkaline compounds, so that the performance of the lithium ion battery is improved, and the service life of the lithium ion battery is prolonged. Therefore, in combination with the multi-dimensional conductive material, the porous structure of the multi-dimensional conductive material can adsorb and intercept the dissolved manganese, and meanwhile, the alkaline compound material can be uniformly distributed in a conductive pore channel, so that the damage to the negative electrode is reduced, and the high-temperature cycle and high-temperature storage performance of the battery is improved.

The invention provides an electrolyte and a secondary battery, the electrolyte comprises a solvent, an additive and an electrolyte, the solvent comprises fluoroethylene carbonate, a compound as shown in a formula I and a compound as shown in a formula II, the mass ratio of fluoroethylene carbonate to fluorochain ester is 1: (0.33-4), the mass ratio of the compound as shown in the formula I to the compound as shown in the formula II is 1: (0.33-3), and the additive and the electrolyte are used for preparing the electrolyte. Based on the mass of the electrolyte, the mass percentage A of the fluorinated solvent is more than or equal to 20% and less than or equal to 80%; the additive comprises tetraethylene silane, based on the mass of the electrolyte, the mass percentage of the tetraethylene silane is M, and M is larger than or equal to 0.02% and smaller than or equal to 3%. Through the arrangement, the fluoroethylene carbonate, the compound as shown in the formula I, the compound as shown in the formula II and the tetraethylene silane have a synergistic effect, so that the electrolyte has proper viscosity and relatively high oxidation resistance, and meanwhile, the negative influence of defluorination on a positive electrode can be improved; therefore, the high-temperature cycle performance and the high-temperature storage performance of the secondary battery under the high-pressure condition are improved.

In order to overcome the problem of insufficient high-temperature storage performance of existing batteries containing silicon-based materials, the present application provides a secondary battery, including a positive electrode, a negative electrode with a negative electrode material layer, and a non-aqueous electrolyte, the negative electrode material layer comprises a negative electrode active material, and the negative electrode active material comprises a silicon-based material; the non-aqueous electrolyte comprises a solvent, an electrolyte salt and an additive, the additives comprises a compound represented by structural formula 1; wherein n is 0 or 1, A is selected from C or O, X is selected from or R1 and R2 are each independently selected from H, R1 and R2 are not selected from H at the same time, and X, R1 and R2 comprise at least one sulfur atom; the secondary battery meets the following requirements: 0.21≤m∗n∗rs≤40; and 40%≤m≤90%, 0.05%≤n≤2%, 1.2g / cm3≤r≤1.8g / cm3, 5%≤S≤30%. The secondary battery provided by the present application can improve the high-temperature storage performance of battery on the premise of ensuring that the battery has excellent energy density.

The invention relates to the field of batteries, in particular to a thiophene compound and a preparation method thereof, an electrolyte and a battery. The structural formula of the thiophene compound is as shown in formula I, specifically, the thiophene compound containing cyano and sulfamido is obtained by carrying out electrophilic aromatic amino sulfonylation reaction on a cyano thiophene compound and an amino sulfonyl chloride compound; the electrolyte comprises a solvent, a lithium salt, an additive and the thiophene compound. The electrolyte provided by the invention comprises the thiophene compound containing the cyano group and the sulfamide group, and the thiophene compound not only can participate in film formation of a positive electrode and a negative electrode, but also can be complexed with transition metal ions dissolved out from the electrolyte, so that the high-temperature performance of the battery is synergistically improved.

The present invention relates to the field of electrochemical technology, and specifically discloses a secondary battery and an electrical device. The positive electrode active material in the positive electrode plate of the present invention includes a lithium manganese iron phosphate material; a secondary battery using the positive electrode plate is subjected to a charge and discharge test at 45°C under 1C / 1C conditions, and a dQ / dV-V graph is drawn; the main reduction peak of the lower potential in the dQ / dV-V graph within the range of 3.0V to 3.85V is peak A, and the main reduction peak of the higher potential is peak B; the peak position difference △V between peak A and peak B and the half-peak width W of peak A satisfy the following relationship: 0.011≤△V 0.2 ×W≤0.145. The present invention controls the redox reaction characteristics of the positive electrode active material so that the secondary battery containing the positive electrode active material has excellent high-temperature cycle characteristics and high-temperature storage performance.