54 results about "Propyl propanoate" patented technology

The invention provides an electrolyte, an electrochemical device and an electronic device, the electrolyte comprises lithium bis (fluorosulfonyl) imide, a sulfur-containing compound and propyl propionate, based on the mass of the electrolyte, the mass percentage content of the lithium bis (fluorosulfonyl) imide is A%, the mass percentage content of the sulfur-containing compound is B%, the mass percentage content of the propyl propionate is D%, B / A is greater than or equal to 0.3 and less than or equal to 4, and D is greater than or equal to 30 and less than or equal to 40. Through the arrangement, the risk that the alternating current impedance of the electrochemical device is increased under high voltage is reduced, and the anti-falling performance and intermittent cycle performance of the electrochemical device are improved.

The invention provides a secondary battery and electronic equipment, the secondary battery comprises a negative electrode plate and an electrolyte, the negative electrode plate comprises a negative electrode active material layer, the negative electrode active material layer comprises graphite and a silicon carbon material, and the average sphericity of the silicon carbon material is 0.81-0.95; the electrolyte comprises ethylene carbonate, propylene carbonate, ethyl propionate and propyl propionate, based on the mass of the electrolyte, the mass percentage content of ethylene carbonate is a%, the mass percentage content of propylene carbonate is b%, the mass percentage content of ethyl propionate is c%, the mass percentage content of propyl propionate is d%, and the range of (a + b) / (c + d) is 0.23-1.51. According to the invention, the discharge performance and the safety performance of the secondary battery at low temperature can be improved.

The invention provides a secondary battery and an electronic device. The secondary battery comprises a positive pole piece, a negative pole piece, electrolyte and an isolating membrane arranged between the positive pole piece and the negative pole piece. The separator film includes a base film and an inorganic coating layer on opposite surfaces of the base film. The inorganic coating includes a plurality of inorganic particles. Dv99 of the inorganic particles is A, and the unit is [mu] m. And the porosity of the base membrane is B%. Wherein the ratio B / A of B to A is greater than or equal to 1.25 and less than or equal to 40. And the electrolyte comprises propyl propionate. Based on the total mass of the electrolyte, the mass percentage content of propyl propionate is C%, and C is more than or equal to 20 and less than or equal to 45. Through the special design of the isolating membrane and the matching of the content control of the propyl propionate in the electrolyte, the secondary battery has low impedance and high safety performance under high-temperature and high-rate charge and discharge, and can effectively prevent overcharge and improve the cycle performance of the secondary battery.

The invention provides an electrolyte, an electrochemical device and an electronic device, and belongs to the technical field of energy storage. Based on the mass of the electrolyte, the electrolyte comprises ethylene carbonate with the mass content of A%, methyl propyl carbonate with the mass content of B%, diethyl carbonate with the mass content of C%, ethyl propionate with the mass content of D% and propyl propionate with the mass content of E%; wherein 5 < = A < = 20, 10 < = B < = 20, and 0.1 < = A / (B + C + D + E) < = 0.5. By controlling the components and the mass content of the electrolyte, the components are matched with one another, so that the high-temperature cycle capacity retention ratio of the battery can be improved, the increase of the thickness of the battery in a high-temperature and high-humidity storage environment is controlled, the service life of the battery is prolonged, and the use safety of the battery is improved.

The invention relates to an electrolyte, a secondary battery and an electronic device. Specifically, the invention provides the electrolyte, the electrolyte comprises propylene carbonate, propyl propionate, butanedinitrile and 1, 3, 6-hexane trinitrile, relative to 100 parts by mass of the electrolyte, the propylene carbonate accounts for 14 to 20 parts by mass, the propyl propionate accounts for 10 to 55 parts by mass, the butanedinitrile accounts for 0.3 to 4 parts by mass, and the 1, 3, 6-hexane trinitrile accounts for 1 to 6 parts by mass; the electrolyte further comprises adiponitrile, and the adiponitrile is 0.05-0.5 part by mass relative to 100 parts by mass of the electrolyte. According to the invention, the low-temperature discharge performance and the over-temperature safety performance of the secondary battery can be improved.

The invention discloses an electrolyte for a soft package cylindrical battery. The electrolyte comprises the following components in parts by weight: 10-25 parts of lithium salt, 60-85 parts of an organic solvent and 5-15 parts of a functional additive, the lithium salt is prepared from 10 to 18 parts of lithium hexafluorophosphate, 2 to 5 parts of lithium bis (fluorosulfonyl) imide and 0.1 to 1 part of lithium difluorophosphate; the organic solvent is prepared from 10 to 20 parts of ethylene carbonate, 30 to 45 parts of propyl propionate, 10 to 20 parts of ethylene carbonate and 5 to 10 parts of propylene carbonate; the functional additive is prepared from 0.5 to 2 parts of vinylene carbonate, 1 to 3 parts of propylene sulfite, 3 to 8 parts of ethylene sulfate, 0.5 to 1.5 parts of fluoroethylene carbonate, 0.1 to 0.5 part of lithium bis (oxalato) borate and 0.1 to 0.5 part of lithium bis (oxalato) borate. The electrolyte disclosed by the invention is applied to the soft package cylindrical battery, the permeability and infiltration efficiency of the electrolyte can be remarkably improved, and the electrochemical performance of the battery is improved.

The invention relates to the technical field of lithium battery production, in particular to a high-safety lithium ion battery manufacturing method, which comprises a positive plate, a negative plate, a diaphragm and an electrolyte, the method comprises the following steps: 1) preparing a positive plate, wherein the positive plate is composed of a positive current collector and a positive material coated on the positive current collector; the electrolyte is a safe electrolyte, the solvent comprises 10%-15% of ethylene carbonate (EC), 30%-35% of diethyl carbonate (DEC), 10%-15% of propylene carbonate (PC) and 20%-25% of propyl propionate (PP), the additives comprise 2%-3% of VC, 2%-3% of PS, 0.5-1% of LiBOB, 1-2% of SN, 2-3% of HTCN, 0.5-0.7% of LiODFB and 0.1-0.3% of FPOP, the electrolyte is LiPF6, the content is 1.1-1.2 mol, the conductivity is larger than or equal to 8.0 ms / cm, Al2O3 ceramic powder is added in the formula of the positive electrode and the negative electrode, and the safety performance is improved; the diaphragm coated with ceramic on both sides is used, and the double-sided ceramic diaphragm is small in thermal shrinkage and high in puncture resistance, so that the safety can be effectively improved.

An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z, wherein about 2.2 wt %≤(X+Y)≤about 8 wt %, about 0.1≤(X / Y)≤about 6, 1 wt %<Y<5 wt %, about 30 wt %≤Z≤about 50 wt %, and about 0.02<(Y / Z)≤about 0.3.

An electrochemical apparatus includes a separator, a positive electrode plate, and an electrolyte solution, where the separator includes a porous layer, and an average pore diameter of the porous layer is 0.5 μm to 18 μm; the electrolyte solution includes propyl propionate, and based on a mass of the electrolyte solution, a mass content of propyl propionate is 25% to 55%; and the positive electrode plate includes a positive active material layer, the positive active material layer includes a conductive agent, the conductive agent includes at least one of conductive carbon black or Ketjen black, and a specific surface area of the conductive agent is 600 m2 / g to 1100 m2 / g.

The invention provides a non-aqueous electrolyte, an electrochemical device and an electronic device. The non-aqueous electrolyte comprises ethylene carbonate, propylene carbonate, propyl propionate and ethyl propionate, and based on the total mass of the non-aqueous electrolyte, the mass contents of ethylene carbonate, propylene carbonate, propyl propionate and ethyl propionate are respectively A%, B%, C% and D%, 5 < = A < = 15, 5 < = B < = 15, 30 < = C < = 50, 5 < = D < = 20, A > = B, 2 < = C / D < = 3.5. When the electrochemical device contains the non-aqueous electrolyte, the cycle performance of the electrochemical device at normal temperature can be improved on the basis of considering the high-temperature performance of the electrochemical device.

Disclosed in the present application are an electrolyte, an electrochemical apparatus and an electronic device. The electrolyte contains a carbonic ester compound and a substance T, wherein the substance T comprises a sulfur-containing compound; the carbonic ester compound comprises at least two of ethyl propionate, propylene carbonate, diethyl carbonate or propyl propionate, and at least contains ethyl propionate; and based on the total mass of the electrolyte, the mass percentage content of the carbonic ester compound is A, and the mass percentage content of the sulfur-containing compound is B, both of which satisfy: 6.5≤A / B≤45. The electrolyte of the present application can alleviate the expansion of a lithium-ion battery during charging and discharging, which is beneficial for improving the overcharge safety performance of the lithium-ion battery at a high temperature.

To provide a secondary battery that reduces a high-temperature internal resistance to improve cycle performance at high voltage, and an electronic apparatus including the secondary battery.SOLUTION: A secondary battery includes a positive electrode, a negative electrode, and an electrolyte. The electrolyte includes an organic solvent, and the organic solvent includes ethyl propionate and propyl propionate. When the mass content of ethyl propionate in the electrolyte is defined as m%, and the mass content of propyl propionate as n%, the difference between n and m (n-m) is 5-54. The negative electrode includes a negative electrode collector, and a negative electrode active material layer provided in the negative electrode collector. The negative electrode active material layer includes a negative electrode active material, the negative electrode active material includes graphite, and n and the Lc value of graphite satisfy that the ratio n / Lc is 1-2.14. The difference in the content between ethyl propionate and propyl propionate included in the electrolyte satisfies a specific request, and the ratio of the mass content n% of propyl propionate to the Lc of graphite (n / Lc) is 1-2.14.SELECTED DRAWING: None

The invention provides an electrochemical device and an electronic device, and belongs to the technical field of energy storage. Wherein the electrochemical device comprises a positive electrode, a negative electrode and an electrolyte; based on the mass of the electrolyte, the electrolyte comprises ethylene carbonate with the mass content of A%, propylene carbonate with the mass content of B%, diethyl carbonate with the mass content of C%, propyl propionate with the mass content of D% and 2, 2-ethyl difluoroacetate with the mass content of E%; 0.3 < = (A + B) / (C + D + E) < = 1.25; 20 < = A < = 30; 20 < = E < = 30. By controlling the components and the mass content of the electrolyte, the components are matched with one another, so that the consumption rate of the electrolyte and the expansion rate of the battery in the circulation process are reduced.

The invention provides a secondary battery and electronic equipment, the secondary battery comprises a negative electrode plate and an electrolyte, the negative electrode plate comprises a negative electrode active material layer, the negative electrode active material layer comprises graphite and a silicon carbon material, the average sphericity of the silicon carbon material is m, and the range of m is 0.81-0.95; the electrolyte comprises ethylene carbonate, propylene carbonate, ethyl propionate and propyl propionate, based on the mass of the electrolyte, the mass percentage content of the ethylene carbonate is a%, the mass percentage content of the propylene carbonate is b%, the mass percentage content of the ethyl propionate is c%, the mass percentage content of the propyl propionate is d%, b ranges from 5 to 26, (a + b) / (c + d) ranges from 0.23 to 1.51, and the sum of the mass percentage content of the ethylene carbonate, the mass percentage content of the propylene carbonate, the mass percentage content of the ethyl propionate and the mass percentage content of the propyl propionate is d%. The electrolyte further comprises lithium difluorophosphate, the mass percentage content of the lithium difluorophosphate is n% based on the mass of the electrolyte, and m / n ranges from 3 to 14.5. According to the invention, the discharge performance and the safety performance of the secondary battery at low temperature can be improved.

The application belongs to the technical field of electrochemistry and relates to a secondary battery and an electronic device comprising the secondary battery. The secondary battery comprises a positive electrode, a negative electrode, a separator and an electrolyte; the negative electrode active material of the negative electrode comprises a silicon-carbon material; the electrolyte comprises ethyl propionate and propyl propionate, the mass percentage content of the ethyl propionate is a% and the mass percentage content of the propyl propionate is b% based on the total mass of the electrolyte, wherein 1.7<=a / b<=5.7; the electrolyte further comprises at least one of vinylene carbonate, a boron-containing lithium salt and a compound comprising a structure shown in Formula I; wherein A in Formula I is selected from C2 to C5 alkylene. The secondary battery, by improving the used electrolyte system, reduces the gas generated by the secondary battery containing the electrolyte system at high temperature, and further improves the high-rate discharge performance of the secondary battery.

The invention relates to the technical field of batteries, in particular to an electrolyte without ethylene carbonate and a battery. The electrolyte comprises fluoroethylene carbonate, diethyl carbonate, propylene carbonate and a compound A, and the compound A is at least one of ethyl propionate and propyl propionate; based on the total mass of the electrolyte, the mass content w1 of the fluoroethylene carbonate is 10-30%; the mass content w5 of the diethyl carbonate is 5%-25%; the content w6 of the propylene carbonate is 5%-28%; the mass content of the compound A is w2, and w2 is 25%-60%; under the condition that the compound A is a combination of ethyl propionate and propyl propionate, the mass content of ethyl propionate is greater than that of propyl propionate; and 1.04 < = w1 / w5 < = 3.5. Comprising the electrolyte provided by the invention is improved in high-temperature stability, dynamic performance and cycle performance.

The invention discloses a secondary battery and an electric device, and belongs to the technical field of batteries. According to the secondary battery provided by the invention, the propionate organic solvent containing propyl propionate and / or ethyl propionate is added into the electrolyte, and meanwhile, the mass percentage a of the silicon-carbon material in the negative electrode active material, the mass percentage b of the hydrogen element in the silicon-carbon material and the mass percentage c of the propionate organic solvent in the electrolyte are controlled; on one hand, the lithium intercalation kinetics of the silicon-carbon material can be accelerated and the transmission capability of lithium ions can be improved on the basis of effectively reducing the side reaction between the silicon-carbon material and an electrolyte under the conditions of normal temperature and high temperature, so that the internal resistance of the secondary battery is reduced, and the cycle performance of the secondary battery under the conditions of normal temperature and high temperature is improved; on the other hand, the excessive increase of the viscosity of the electrolyte under the high voltage condition can be relieved, and the floating charge performance of the secondary battery under the high voltage condition is improved.

A secondary battery is provided and includes an exterior member having flexibility, and a positive electrode, a negative electrode, and an electrolytic solution that are housed in the exterior member. The electrolytic solution contains a solvent and an electrolyte salt, and the solvent contains propyl acetate and propyl propionate. The ratio of the content of propyl acetate in the solvent to the sum of the content of propyl acetate in the solvent and the content of propyl propionate in the solvent is 0.1 or more and 0.5 or less.

Disclosed in the present application are an electrolyte, an electrochemical apparatus and an electronic device. The electrolyte contains a carbonic ester compound and a substance T, wherein the substance T comprises a sulfur-containing compound; the carbonic ester compound comprises at least two of ethyl propionate, propylene carbonate, diethyl carbonate or propyl propionate, and at least contains ethyl propionate; and based on the total mass of the electrolyte, the mass percentage content of the carbonic ester compound is A, and the mass percentage content of the sulfur-containing compound is B, both of which satisfy: 6.5≤A / B≤45. The electrolyte of the present application can alleviate the expansion of a lithium-ion battery during charging and discharging, which is beneficial for improving the overcharge safety performance of the lithium-ion battery at a high temperature.

A secondary battery includes: a positive electrode containing a lithium-nickel composite oxide; a negative electrode containing a lithium-titanium composite oxide; and an electrolyte containing a carboxylic acid ester containing at least one of ethyl acetate, propyl acetate, ethyl propionate, and propyl propionate. In surface analysis of the positive electrode using X-ray photoelectron spectroscopy, a first oxygen spectrum having a peak in a range of a binding energy of 528 eV or more and 531 eV or less, and a second oxygen spectrum having a peak in a range of a binding energy of more than 531 eV and 535 eV or less are detected, and a ratio of an intensity of the first oxygen spectrum to an intensity of the second oxygen spectrum is 0.30 or more and 0.80 or less. In surface analysis of the negative electrode using X-ray photoelectron spectroscopy, a third oxygen spectrum having a peak in a range of a binding energy of 528 eV or more and 531 eV or less, and a fourth oxygen spectrum having a peak in a range of a binding energy of more than 531 eV and 535 eV or less are detected, and a ratio of an intensity of the third oxygen spectrum to an intensity of the fourth oxygen spectrum is 0.82 or more and 1.35 or less.

A lithium-ion battery. The lithium-ion battery comprises a positive electrode sheet and an electrolyte solution, wherein the positive electrode sheet comprises a positive electrode current collector, a positive electrode active material layer located on one side or two sides of the positive electrode current collector, and a primer layer located between the positive electrode current collector and the positive electrode active material layer, the primer layer having a weight loss rate of X% at 25-800°C; the electrolyte solution comprises propylene carbonate and propyl propionate, and based on the total weight of the electrolyte solution, the weight content of propylene carbonate is B wt%, and the weight content of propyl propionate is C wt%; and the lithium-ion battery satisfies: 5≤(B+C) / X≤30. The lithium-ion battery has the advantages of both high safety performance and good cycle performance.

An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z, wherein, about 2 wt %<(X+Y)≤about 11 wt %, about 0.1≤(X / Y)≤about 4, about 30 wt %≤Z≤about 50 wt %, about 2 wt %<X≤about 6 wt %, and about 0.01<(Y / Z)≤about 0.3; wherein the trinitrile compound comprises at least one selected from the group consisting of 1,3,5-pentanetricarbonitrile; 1,2,3-propanetrinitrile, 1,3,6-hexanetricarbonitrile; 1,2,6-hexanetricarbonitrile, 1,2,3-tris(2-cyanoethoxy)propane; 1,2,4-tris(2-cyanoethoxy)butane, 1,1,1-tris(cyanoethoxymethylene)ethane, 1,1,1-tris(cyanoethoxymethylene)propane, 3-methyl-1,3,5-tris(cyanoethoxy)pentane, 1,2,7-tris(cyanoethoxy)heptane, 1,2,6-tris(cyanoethoxy)hexane, and 1,2,5-tris(cyanoethoxy)pentane.

An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z, wherein, about 3 wt %≤(X+Y)≤about 11 wt %, about 1≤(X / Y)≤about 6, and about 0.01<(Y / Z)≤about 0.3; the trinitrile compound includes at least one selected from the group of 1,3,5-pentanetricarbonitrile; 1,2,3-propanetrinitrile, 1,3,6-hexanetricarbonitrile; 1,2,6-hexanetricarbonitrile, 1,2,3-tris(2-cyanoethoxy)propane; 1,2,4-tris(2-cyanoethoxy)butane, 1,1,1-tris(cyanoethoxymethylene)ethane, 1,1,1-tris(cyanoethoxymethylene)propane, 3-methyl-1,3,5-tris(cyanoethoxy)pentane, 1,2,7-tris(cyanoethoxy)heptane, 1,2,6-tris(cyanoethoxy)hexane, and 1,2,5-tris(cyanoethoxy)pentane.

According to the propyl alcohol rectification system provided by the invention, heavy components such as propyl alcohol and propyl propionate in crude propyl alcohol can be separated through rectification of the propyl alcohol rectification tower and negative pressure rectification of the waste liquid rectification tower, so that the purposes of purifying and recovering the propyl alcohol are achieved, and the economic benefit is improved. Heat pump devices such as a heat pump compressor, a heat pump separator and a heat pump reboiler are also introduced into the system, so that the stability and the reliability of the operation of the rectifying tower are favorably maintained, and unstable production factors caused by fluctuation of energy supply are reduced. In addition, the heat pump device can recycle part of heat in the rectification process and reuse the heat, so that the energy consumption in the rectification process is remarkably reduced, and the energy utilization efficiency is improved.

A secondary battery, including a negative electrode plate and an electrolyte, where the negative electrode plate includes a negative electrode active material layer. The negative electrode active material layer includes graphite and a silicon-carbon material, and an average sphericity of the silicon-carbon material is 0.81 to 0.95. The electrolyte includes ethylene carbonate, propylene carbonate, ethyl propionate and propyl propionate, where based on a mass of the electrolyte, a mass percentage of the ethylene carbonate is a %, a mass percentage of the propylene carbonate is b %, a mass percentage of the ethyl propionate is c %, a mass percentage of the propyl propionate is d %, and (a+b) / (c+d) is in a range of 0.23 to 1.51.

The application provides a wide-temperature lithium ion battery electrolyte and a lithium ion battery thereof, wherein the lithium ion battery electrolyte comprises a lithium salt, a nonaqueous organic solvent and an additive; the nonaqueous organic solvent comprises a first carbonate, a second carbonate, a third carbonate, a fourth carbonate and a carboxylic acid ester; the first carbonate is dimethyl carbonate and the volume percentage is 39-51%; the second carbonate is propylene carbonate and the volume percentage is 10-15%; the third carbonate is ethylene carbonate and the volume percentage is 8-15%; the fourth carbonate is methyl ethyl carbonate and / or diethyl carbonate and the volume percentage is 8-10%; and the carboxylic acid ester is one or more of propyl acetate, propyl propionate and ethyl propionate and the volume percentage is 19-26%. On the basis of the synergistic effect of dimethyl carbonate and propylene carbonate, the addition of ethylene carbonate, the fourth carbonate and the linear carboxylic acid ester can make the lithium ion battery have better high and low temperature performance.

The invention provides an electrolyte, an electrochemical device and an electronic device, the electrolyte comprises lithium bis (fluorosulfonyl) imide, a sulfur-containing compound and propyl propionate, based on the mass of the electrolyte, the mass percentage content of the lithium bis (fluorosulfonyl) imide is A%, the mass percentage content of the sulfur-containing compound is B%, the mass percentage content of the propyl propionate is D%, B / A is greater than or equal to 0.3 and less than or equal to 4, and D is greater than or equal to 30 and less than or equal to 40. Through the arrangement, the risk that the alternating current impedance of the electrochemical device is increased under high voltage is reduced, and the anti-falling performance and intermittent cycle performance of the electrochemical device are improved.

The invention provides a battery and electric equipment, the battery comprises an electrolyte, an organic solvent in the electrolyte comprises ethyl propionate and propyl propionate, a positive plate is provided with at least two positive tabs, and a negative plate comprises a negative current collector and a negative active layer arranged on the negative current collector. Part of the negative electrode current collector is exposed out of the negative electrode active layer and forms a negative electrode lug groove, a negative electrode lug is welded in the negative electrode lug groove, the battery meets the condition that A / B is larger than or equal to 2, and when the amount of the carboxylic ester solvent added into the electrolyte is adjusted and meets the relation of the ratio of the total welding printing area of the negative electrode lug to the area of the negative electrode lug groove, the total welding printing area of the negative electrode lug is larger than or equal to 2. And lithium precipitation at a negative electrode lug position can be improved.

An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z, wherein, about 2 wt %≤(X+Y)≤about 11 wt %, about 1≤(X / Y)≤about 6, about 40 wt %≤Z≤about 50 wt %, and about 0.01<(Y / Z)≤about 0.3; wherein the trinitrile compound comprises at least one selected from the group consisting of 1,3,5-pentanetricarbonitrile; 1,2,3-propanetrinitrile, 1,3,6-hexanetricarbonitrile; 1,2,6-hexanetricarbonitrile, 1,2,3-tris(2-cyanoethoxy)propane; 1,2,4-tris(2-cyanoethoxy)butane, 1,1,1-tris(cyanoethoxymethylene)ethane, 1,1,1-tris(cyanoethoxymethylene)propane, 3-methyl-1,3,5-tris(cyanoethoxy)pentane, 1,2,7-tris(cyanoethoxy)heptane, 1,2,6-tris(cyanoethoxy)hexane, and 1,2,5-tris(cyanoethoxy)pentane.

The invention discloses an electrolyte and a secondary battery, and belongs to the technical field of batteries. The electrolyte provided by the invention is prepared from the following components in percentage by mass: 1.0 percent to 5.0 percent of ethylene carbonate, 28.0 percent to 49.0 percent of propyl propionate, 6.0 percent to 10.0 percent of fluoroethylene carbonate, 0.5 percent to 2.0 percent of adiponitrile, 1.0 percent to 3.5 percent of 1, 3, 6-hexanetrinitrile and 0 to 1.2 percent of tris (pentafluorophenyl) borane. And the molar weight of nitrile groups in the electrolyte is greater than or equal to the molar weight of cobalt active sites on the surface of lithium cobalt oxide in the positive pole piece. The electrolyte enables the secondary battery to have good normal-temperature cycle performance and good high-temperature storage performance.