Battery

Abstract

A battery characterized in that it comprises a cathode foil, wherein the cathode foil comprises an active cathode material, the active cathode material comprising a lithium manganese iron phosphate material and a nickel-based cathode material, the nickel-based cathode material containing trivalent nickel elements and tetravalent nickel elements, wherein a molar ratio of the nickel-based cathode material to the active cathode material c is, wherein, when the battery is in a state of 100% SOC, a percentage of the total molar amount of the trivalent nickel elements and the tetravalent nickel elements to the total molar amount of the nickel elements in the nickel-based cathode material a is, wherein a + -growth rate of the cathode foil b is, where a, c and b satisfy a relational equation represented in Formula I: 0.008 < (a × c) / b ≤ 8.290.

Description

Technical field

[0001] The present invention relates to the technical field of lithium-ion batteries, in particular a battery. Technical background

[0002] The LMFP (lithium manganese iron phosphate) material consists of the elements manganese (Mn), iron (Fe), phosphorus (P) and lithium (Li), and lithium manganese iron phosphate has become a material of great interest for new energy vehicles and energy storage systems as a cathode material for lithium batteries, due to its high performance, stability and cost-effectiveness.

[0003] However, the large specific surface area of ​​the LMFP material and its large contact area with the electrolyte solution exacerbate the hydrogen protonation of the electrolyte solution, and the protonated hydrogen is reduced to hydrogen at the anode, resulting in significant gas generation. This gas generation leads to electrode expansion, poor electrode-separator contact, increased impedance, and black spots on the electrode.

[0004] Therefore, the development of a lithium-ion battery that reduces gas production is a problem that needs to be solved. Content of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a battery, and the battery provided by the present invention can significantly reduce the amount of gas production, ensure that the contact between the electrode and the separator of the battery is tight, and thus reduce the internal resistance of the battery and improve the cycle performance of the battery.

[0006] The present invention provides a battery comprising a cathode foil, wherein the cathode foil comprises an active cathode material, the active cathode material comprising a lithium manganese iron phosphate material and a nickel-based cathode material, the nickel-based cathode material containing trivalent nickel elements and tetravalent nickel elements, wherein a molar ratio of the nickel-based cathode material to the active cathode material c is, wherein, when the battery is in a state of 100% SOC, a percentage of the total molar amount of the trivalent nickel elements and the tetravalent nickel elements to the total molar amount of the nickel elements in the nickel-based cathode material a is, wherein a + -growth rate of the cathode foil b is, where a, c and b satisfy a relational equation represented in Formula I: 0.008<(a×c) / b≤8.290.

[0007] In comparison to the prior art, the present invention allows for the control of the percentage of the total molar amount of trivalent nickel and tetravalent nickel in the lithium-ion battery relative to the total molar amount of nickel in the nickel-based cathode material, the molar ratio of the nickel-based cathode material to the active cathode material, and the growth rate of H + The cathode foil significantly reduces the amount of gas produced by the battery and ensures close contact between the battery's electrode foil and the separator, thereby reducing the battery's internal resistance and improving its cycle performance. Description of embodiments

[0008] The present invention provides a battery comprising a cathode foil, wherein the cathode foil comprises an active cathode material, the active cathode material comprising a lithium manganese iron phosphate material and a nickel-based cathode material, wherein a molar ratio of the nickel-based cathode material to the active cathode material is c, wherein the nickel-based cathode material contains trivalent nickel elements and tetravalent nickel elements, wherein a percentage of the total molar amount of the trivalent nickel elements and the tetravalent nickel elements in the total molar amount of the nickel elements in the nickel-based cathode material is a, wherein a H + -growth rate of the cathode foil b is, where a, c and b satisfy a relational equation represented in Formula I: 0.008<(a×c) / b≤8.290.

[0009] If a, b, and c satisfy the relational equation shown in Formula I, the problems of gas generation and expansion in the battery are significantly improved, and there are no problems with black spots. The problem of gas generation in the battery is closely related to the values ​​of a, b, and c. The greater the growth rate of H + The higher the number of -ions, the larger b is, and gas production is significant. At this point, a sufficient amount of high-valent Ni-ions (a) is introduced, and the catalytic oxidation activity of the Ni-ions is stronger than that of the Mn-ions, causing further oxidation of protonated hydrogen and the production of CO, CO2, and other absorbable gases, thus changing the gas production pathway and reducing the production of hydrogen gas.

[0010] If the calculated value of (a×c) / b exceeds the upper limit of the relationship equation, i.e., exceeds the maximum value, it may be that the content of tetravalent and trivalent nickel elements is too high, which impairs and reduces the battery's capacity, and it may also be that the H + H + -The growth rate b is too small, and the value of b is too small, meaning that the surface-active area of ​​the cathode is small, leading to a higher diffusion impedance of lithium ions and poorer battery kinetics; if the lower limit of the relationship equation is exceeded, i.e., the minimum value is exceeded, the growth rate of H may be +The number of -ions is too large, resulting in a larger active area of ​​the cathode, which leads to serious dissolution of transition metal ions and destruction of the SEI, leading to poorer kinetics, an increase in DCR, and a deterioration of the cycle life. It is also possible that the content of trivalent and tetravalent nickel elements in the cathode material is low across the entire active cathode material, which may not affect the gas generation pathway, and that hydrogen emissions are too high, compromising battery safety.

[0011] Therefore, by controlling the values ​​of a, b and c to meet the range of 0.008<(a×c) / b≤8.290, the present invention can significantly reduce the amount of battery gas generation and ensure that the contact between the electrode and the separator of the battery is tight, thus reducing the internal resistance of the battery and improving the cycle performance of the battery. In the present invention, (axc) / b can be 0.009, 0.010, 0.02, 0.025, 0.03, 0.05, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0, 1.5, 2.0, 2.5, 2.86, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.290 or any value between 0.008 and 8.290.

[0012] In the present invention, the lithium manganese iron phosphate has a structural formula of LiMn x Fe y M z nPO4, where M is a doped metal element, where 0 <x< 1, 0<y<1, 0≤ z< 1, und 2(x+y)+nxz=2, wobei n eine Wertigkeitsstufe des dotierten Metallelements M ist, wobei das dotierte Element M aus mindestens einem der Elemente von Be, Ca, Mg, Ba und Sr ausgewählt ist. Die Lithium-Mangan-Eisen-Phosphat-Material in dem Ausführungsbeispiel der vorliegenden Erfindung verwendet wird, ist beispielsweise durch LiMn 0,6 Fe 0,4 PO4, but is not limited to such lithium manganese iron phosphate material.

[0013] In a preferred embodiment of the present invention, the percentage of the total molar amount of trivalent nickel elements and tetravalent nickel elements to the total molar amount of nickel elements in the nickel-based cathode material, the molar ratio of the nickel-based cathode material to the active cathode material, and the H+ growth rate of the cathode foil satisfy the following relationship equation: 0,025<(a×c) / b≤2,860.

[0014] In the present invention, the active cathode material comprises a lithium manganese iron phosphate material and a nickel-based cathode material, wherein, when the battery is in a state of 100% SOC, the nickel-based cathode material contains trivalent nickel elements and tetravalent nickel elements, wherein a percentage of the total molar amount of the trivalent nickel elements and the tetravalent nickel elements to the total molar amount of the nickel elements in the nickel-based cathode material is a.The larger the value of a, the greater the percentage of the total molar amounts of trivalent and tetravalent nickel elements relative to the total molar amount of nickel elements in the nickel-based cathode material; the smaller the value of a, the smaller the percentage of the total molar amounts of trivalent and tetravalent nickel elements relative to the total molar amount of nickel elements in the nickel-based cathode material.

[0015] The catalytic oxidation activity of trivalent and tetravalent nickel ions is stronger than that of Mn ions, which can further oxidize protons of hydrogen and produce gases that can be absorbed by the electrode, such as CO, CO2, etc., thus altering the gas production pathway to reduce hydrogen gas generation. The value of a depends on the amount of lithium nickel oxygen (LNO) and nickel-containing ternary cathode material added. If the value of a is too high, battery manufacturing costs increase; if the value of a is too low, the desired effect of altering the gas production pathway cannot be achieved.

[0016] In the present invention, 0.3% ≤ a ≤ 23%, and a can be 0.3%, 0.5%, 0.7%, 1%, 3%, 5%, 7%, 9%, 10%, 12%, 14%, 15%, 17%, 19%, 20%, 21%, 23%, or any value between 0.3% and 23%. In some preferred embodiments of the present application, 1% ≤ a ≤ 20%.

[0017] By controlling the value a in the range of 0.3% <a<23% kann in der vorliegenden Erfindung sichergestellt werden, dass der Effekt der Änderung des Gaserzeugungsweges der Batterie unter der Bedingung einer kostengünstigen Herstellung der Batterie erreicht werden kann.

[0018] The present invention is not limited to the test method of a, and a person skilled in the art can test the percentage of the total molar amount of trivalent nickel elements and tetravalent nickel elements relative to the total molar amount of nickel elements in the nickel-based cathode material using conventional technical means. For example, the test method of a comprises the following steps:

[0019] After the cathode foil has been cleaned in a fully charged state at 100% SOC of the battery, the peak area of ​​each valence state of the nickel cell in the cathode foil is tested using XPS. a is calculated according to the equation shown in Formula II: a=(SNi4++SNi3+) / Stotal area;

[0020] In Formula II, S denotes Ni 4+ the area of ​​tetravalent nickel determined by XPS testing;

[0021] S Ni 3+denotes the area of ​​trivalent nickel determined by XPS testing;

[0022] S Gesamtfläche denotes the sum of the peak areas of the individual valence states of the nickel element obtained by the XPS test.

[0023] In particular, the testing procedure includes the following steps:

[0024] Disassemble the cathode foil in a fully charged state of the battery at 100% SOC, clean the cathode foil with DMC (dimethyl carbonate) and then dry it to obtain the treated cathode foil.

[0025] In the present invention, there are no particular restrictions regarding the drying method, and the drying method known to those skilled in the art is sufficient. Vacuum drying is preferred in the present invention, the drying temperature is preferably 25°C, and the drying time is preferably 24 hours.

[0026] After receiving the treated cathode foil, it is etched using X-ray photoelectron spectroscopy (XPS) at an etch rate of 0.7 nm / s and an etch time of 60 s. The peak area of ​​each valence state is adjusted according to the binding energy and the sum of the peak areas of the trivalent and tetravalent nickel elements obtained by testing, as well as the total peak area of ​​the nickel element in all valence states. The value of a in % is obtained by calculation according to the equation shown in Formula II.

[0027] In some preferred embodiments of the present invention, the molar ratio between the trivalent nickel element and the tetravalent nickel element is 1:10 to 6:10 and can be 1:10, 1.5:10, 2:10, 2.5:10, 3:10, 3.5:10, 4:10, 4.5:10, 5:10, 5.5:10, 6:10, or any value between 1:10 and 6:10. An excessively high molar ratio of trivalent nickel elements to tetravalent nickel elements means that too many trivalent nickel elements are present, which are less effective when modifying the gas production pathway to reduce hydrogen production.The ratio is too small, which corresponds to an insufficient content of trivalent nickel elements, and the battery life decreases significantly; if the molar ratio between trivalent and tetravalent nickel elements is in the range of 1:10 to 6:10, not only can the gas production pathway be effectively modified to reduce hydrogen production, but at the same time the battery life is maintained, and the battery life does not decrease too rapidly.

[0028] In the present invention, the nickel-based cathode material is selected from one or more lithium-nickel-oxygen cathode materials or nickel-containing ternary cathode materials.

[0029] In some specific embodiments of the present invention, the nickel-containing ternary cathode material is selected from a ternary cathode material made of nickel-cobalt-manganese, wherein the ternary nickel-cobalt-manganese material is LiNi x Co y Mn 1-x-y O2 is, where 0.9 <x<1 und 0<y<0,1 ist, und x+y≠1.

[0030] In the present invention there is no particular restriction to the source of the cathode material being lithium nickel oxygen or nickel-containing ternary cathode material, which may be a commercially available product or may be produced by a manufacturing process known to those skilled in the art.

[0031] In the present invention, the manufacturing process for the lithium-nickel-oxygen cathode material is not limited, and those skilled in the field can produce and obtain the active cathode material using conventional technical means. For example, the manufacturing process for the lithium-nickel-oxygen cathode material comprises the following steps:

[0032] First, the lithium source and nickel source required for the synthesis of the lithium-nickel-oxygen material are weighed according to the ratio and added to deionized water, ground, washed and spray-dried to obtain a dry powder of the lithium-nickel-oxygen material, and the dry powder is sintered under a protective atmosphere, and the lithium-nickel-oxygen cathode material is obtained after cooling.

[0033] In the present invention, the manufacturing process for LiNi is described. x Coy Mn 1-x-y O2 is not limited, and experts in the field can produce and obtain the nickel-based cathode material using conventional technical means. For example, the nickel-based cathode material precursor and the lithium source are mixed and sintered to obtain the nickel-based cathode material.

[0034] The precursor of the nickel-based cathode material can consist of one or more oxides, hydroxides, and carbonates containing Ni, Co, and Mn in a stoichiometric ratio, such as a hydroxide containing Ni, Co, and Mn in a stoichiometric ratio. The precursor of the active cathode material can be obtained by established technical methods, such as co-precipitation, gel synthesis, or solid-phase synthesis.

[0035] For example, the Ni source, the Co source, and the Mn source are dispersed in a solvent to obtain a mixed solution; the mixed solution, the strong alkali solution, and the complexing agent solution are simultaneously pumped into a reaction vessel under stirring by means of a continuous parallel flow reaction; the pH of the reaction solution is controlled to be between 10 and 13; the temperature inside the reaction vessel is between 25°C and 90°C; and the reaction is protected by the passage of inert gas during the reaction.

[0036] After completion of the reaction, the hydroxide containing Ni, Co and Mn is obtained by aging, filtration, washing and vacuum drying.

[0037] In some embodiments of the present invention, the Ni source comprises at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel oxalate or nickel acetate; and / or the Co source comprises at least one of cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt oxalate or cobalt acetate; and / or the Mn source comprises at least one of the following elements: manganese sulfate, manganese nitrate, manganese chloride, manganese oxalate or manganese acetate; and / or the Li source comprises at least one of lithium oxide (Li2O), lithium phosphate (Li3PO4), lithium dihydrogen phosphate (LiH2PO4), lithium acetate (CH3COOLi), lithium hydroxide (LiOH), lithium carbonate (Li2CO3) or lithium nitrate (LiNO3).

[0038] The precursor of the active cathode material and the lithium source can be mixed using a ball mill mixer or a high-speed mixer. The mixed material is then placed in an atmospheric sintering furnace for sintering. The sintering atmosphere is an oxygen-containing atmosphere, such as air or oxygen.

[0039] Furthermore, the nickel-based cathode material can be coated. Specifically, the coating material is applied to the surface of the nickel-based cathode material by dry coating (high-temperature solid-state process), and the surface of the nickel-based cathode material is partially or completely covered by the coating layer formed by the coating material. The coating layer comprises at least one element (hereinafter referred to as the "coating element") selected from the following: aluminum (Al), titanium (Ti), tungsten (W), boron (B), phosphorus (P), cobalt (Co), yttrium (Y), and silicon (Si).

[0040] Furthermore, the nickel-based cathode material has a particle size of 40 to 200 nm.

[0041] In the present invention, the active cathode material further comprises a lithium manganese iron phosphate material, and the lithium manganese iron phosphate material has a particle size of 50 to 170 nm.

[0042] In the present invention there is no particular restriction on the source of the lithium manganese iron phosphate material, which may be a commercially available product or may be produced by a manufacturing process known to those skilled in the art.

[0043] In the present invention, the manufacturing process for the lithium manganese iron phosphate material is not limited, and those skilled in the field can produce and obtain the lithium manganese iron phosphate material using conventional technical means. For example, the manufacturing process of the lithium manganese iron phosphate material comprises the following steps:

[0044] Weighing and adding a lithium source, a manganese source, an iron source and a phosphorus source required for the synthesis of a lithium manganese iron phosphate material in the correct ratio, adding deionized water and grinding to obtain a lithium manganese iron phosphate precursor slurry;

[0045] Adding a carbon source and uniformly mixing with the lithium manganese iron phosphate precursor slurry, milling, regulating the solids content and spray drying to obtain a dry powder; sintering the dry powder under a protective atmosphere and cooling to obtain the active cathode material.

[0046] In the present invention, the lithium source is selected from at least one of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxalate, lithium dihydrogen phosphate, lithium citrate, and lithium acetate. The manganese source is selected from at least one of manganese carbonate, manganese sulfate, manganese nitrate, manganese chloride, manganese oxalate, and manganese acetate. The iron source is selected from at least one of di-iron oxalate, iron(III) hydroxide, iron(II) hydroxide, iron(III) phosphate, iron(II) phosphate, iron(III) acetate, iron(II) acetate, iron(III) carbonate, iron(II) carbonate, iron(III) oxide, iron(III) oxide, iron(III) oxide, and iron(III) oxalate. The phosphorus source is selected from at least one of diammonium hydrogen phosphate, lithium dihydrogen phosphate, ammonium phosphate, and lithium phosphate.In the present invention, ferromanganese phosphate is preferably used to act simultaneously as a manganese source, iron source, and phosphorus source; or preferably, iron phosphate is used to act simultaneously as an iron source and phosphorus source. The carbon source comprises glucose.

[0047] The raw materials can be mixed using a ball mill mixer or a high-speed mixer. The mixed raw material is then dried to obtain the precursor.

[0048] Adding the precursor to an atmospheric sintering furnace for sintering. The sintering atmosphere is an oxygen-containing atmosphere, such as air or oxygen.

[0049] Furthermore, the lithium manganese iron phosphate material can be coated. Specifically, the coating material is applied to the surface of the lithium manganese iron phosphate material by dry coating (high-temperature solid-state process), and the surface of the lithium manganese iron phosphate material is partially or completely covered by the coating layer formed by the coating material. The coating layer comprises at least one element (hereinafter referred to as the "coating element") selected from the following: aluminum (Al), titanium (Ti), tungsten (W), boron (B), phosphorus (P), cobalt (Co), yttrium (Y), and silicon (Si).

[0050] In the present invention, the molar ratio c of the nickel-based cathode material to the active cathode material can similarly influence the gas production of the battery as well as the performance of the battery.

[0051] The larger the value c, the greater the proportion of nickel-based material to the total active material and the lower the proportion of LMFP. While this can alter the battery's gas generation pathway and reduce hydrogen production, the lower proportion of LMFP also significantly reduces the battery's capacity. Conversely, the smaller the value c, the lower the proportion of nickel-based material in the total active material. This means it cannot exert a uniform inhibitory effect on the gas generation of the entire electrode foil, leading to excessive hydrogen production and thus compromising battery safety.

[0052] Therefore, the present invention can ensure battery capacity by controlling the value c in the range of 0.5%≤c≤40% and simultaneously exert a uniform inhibitory effect on gas production of the entire electrode.

[0053] In the present invention, the value c is in the range of 0.5% to 40% and can be 0.5%, 1%, 3%, 5%, 6%, 7%, 10%, 12%, 14%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, 32%, 34%, 35%, 37%, 40%. In some preferred embodiments of the present invention, the value c is in the range of 5% to 30%.

[0054] The present invention is not limited to the test method of c, and the person skilled in the art can test the molar ratio of the nickel-based cathode material to the active cathode material using conventional technical means. For example, the test method for c comprises the following steps:

[0055] Discharge the battery from 0.33C to 2.5V at 25°C, disassemble the battery to obtain a cathode foil and an anode foil, and recover 2g of cathode powder from the cathode foil and 2g of anode powder from the anode foil; use an inductively coupled plasma (ICP) to determine the percentage molar content of the elements Ni and Mn in the cathode powder and anode powder, selecting the wavelengths of the spectra for element detection (the wavelength of Mn was 257.61 nm and the wavelength of Ni was 232.0 nm).In accordance with the properties of the samples and the elements to be detected, the appropriate operating conditions for the ICP apparatus were determined, including a gas flow rate of 0.5 l / min and a power of 1150 W; the Mn and Ni content of the elements contained therein was tested by ICP, and the molar percentage of the nickel-based cathode material in the active cathode material, c, was calculated according to the equation shown in Formula VI. c=(Total mol percent of Ni elements in the cathode and anode powders / Total mol percent of Ni and Mn elements in the cathode and anode powders×100%.

[0056] In the present invention, the H + -Growth rate b also affects the gas production of the battery as well as the battery's performance.

[0057] The H +The growth rate b indicates the size of the active area of ​​the electrode foil; the larger the H+ growth rate b, the larger the active area of ​​the electrode foil, and the smaller the H+ growth rate b, the smaller the active area of ​​the electrode foil. + -The higher the growth rate b, the smaller the active area of ​​the electrode foil, and the larger and smaller H +The growth rate b is related to the degree of carbon encapsulation of the active material, the particle size, the type of distribution, and other factors. The higher the value of b, the simpler the electrochemical reaction at the electrode, or the faster the reaction rate. If the value of b is too high, the active material reacts too strongly with the electrolyte solution, which can easily trigger too many side reactions, leading to excessive gas production and black spots on the electrode. If the value of b is too low, this indicates that the electrochemical reaction is difficult to carry out effectively, probably because the solid-phase diffusion impedance, caused by the large particle size of the active cathode material and an excessively thick carbon layer, is high, resulting in poor overall battery kinetics.

[0058] Therefore, in the present invention it is necessary to control the H+ growth rate b in the range of 0.01 ≤ b ≤ 0.18, and the value of b can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or any value between 0.01 and 0.18. In some preferred embodiments of the present invention, the value of b is 0.02 ≤ b ≤ 0.15.

[0059] By controlling the range of b to 0.01≤b≤0.18, the present invention can ensure that the electrochemical reaction is carried out effectively while improving the reaction rate as much as possible.

[0060] The present invention is not limited to the test procedure of b, and the technicians on site can perform the H + Determine the growth rate using conventional technical means. For example, the test procedure for the H+ growth rate b comprises the following steps:

[0061] Exchanging two groups of cathode foils with the same area from the same fully charged battery at 100% SOC into solutions of the same volume, wherein one group of the cathode foils is stored for 48 hours at 60°C, the H+ content in the solution being measured as m1 in the unit ppm; wherein another group of the cathode foils is stored for 72 hours at 60°C, the H + -Content in the solution is measured as m2 in the unit ppm; where the H + -Growth rate b is calculated according to the equation shown in Formula III: b=(m2−m1) / m1;

[0062] The cathode foil has a test area of ​​147 cm². 2 on, with a test area of ​​147 cm² 2the sum of the areas of a plurality of cathode foils of a battery in a fully charged state and in some specific embodiments of the present invention three cathode foils of a battery in a fully charged state of 7×7 cm 2 They can be.

[0063] The solution is a mixed solution of ethylene vinyl carbonate EC, methyl ethyl carbonate EMC and lithium perchlorate; in the mixed solution, the concentration of lithium perchlorate is 1 M, the volume ratio of ethylene vinyl carbonate EC to methyl ethyl carbonate EMC is 3:7, and the amount of solution is 20 ml.

[0064] In particular, the test procedure for the H includes + -Content in a solution stored for 48 hours, the following steps:

[0065] Configure triethylamine and EMC to form a 0.05 mol / L triethylamine titrant;

[0066] Mix EC and EMC to a 20 mL mixture in a volume ratio of 3:7 and add 2.13 g of lithium perchlorate to the mixture to obtain a soaking solution;

[0067] Mixing the cathode foil of a battery with a test area of ​​147 cm² 2 In a fully charged state, immerse the cathode foil in the soaking solution for 48 hours at 60°C to obtain a 48-hour soaking solution. Add 10 to 30 drops of methyl red as an indicator to the 48-hour soaking solution. Add the triethylamine titrant dropwise to the 48-hour soaking solution containing the methyl red and record the amount V1 of triethylamine titrant when the 48-hour soaking solution turns orange. Calculate the amount of H + in the solution stored for 48 hours, m1, according to formula IV; m1=M×V1×20010 / m;

[0068] In formula IV, M is the concentration of the titrant in mol / L; V1 is the volume of titrant consumed in mL; m is the mass of the soaking solution in g;

[0069] Similarly, the test procedure for the H + -Content of the solution stored for 72 hours, the following steps:

[0070] Configure triethylamine and EMC to form a 0.05 mol / L triethylamine titrant;

[0071] Mix EC and EMC to a 20 mL mixture in a volume ratio of 3:7 and add 2.13 g of lithium perchlorate to the mixture to obtain a soaking solution;

[0072] Mixing the cathode foil of a battery with a test area of ​​147 cm² 2In the fully charged state, immerse the cathode foil in the soaking solution for 48 hours at 60°C to obtain a 72-hour soaking solution. Add 10 to 30 drops of methyl red as an indicator to the 72-hour soaking solution. Add the triethylamine titrant dropwise to the 72-hour soaking solution containing the methyl red and record the amount V2 of triethylamine titrant when the 72-hour soaking solution turns orange. Calculate the amount of H + in the solution stored for 72 hours, m2, according to formula V; m1=M×V2×20010 / m;

[0073] In formula IV, M is the concentration of the titrant in mol / L; V1 is the volume of titrant consumed in mL; m is the mass of the soaking solution in g.

[0074] The H +-The growth rate b is calculated by inserting the values ​​m1 and m2 obtained above into formula III.

[0075] In the present invention, the values ​​of a and b are measured under a battery condition of 100% SOC and c under a battery condition of 0% SOC; In the present invention, a battery discharged from 0.33C to 2.5V at 25°C is defined as 0% SOC.

[0076] In the equation shown in Formula I, a×c can, to a certain extent, reflect the content of trivalent and tetravalent nickel elements in the cathode material of the entire active cathode material. The larger the value of a×c, the higher the content of trivalent and tetravalent nickel elements, and the smaller the value of a×c, the lower the content of trivalent and tetravalent nickel elements in the entire active cathode material.

[0077] In the present invention, the value range of a×c is controlled such that the range 0.001 ≤ a×c ≤ 0.092 is satisfied. If the value of a×c is less than 0.01, this means that the content of trivalent and tetravalent nickel elements in the electrode foil is low, which leads to a decrease in the improvement performance of the nickel-containing material in the gas generation path after the nickel-containing material is added to the electrode foil; that is, the performance of the nickel-containing material in inhibiting hydrogen production decreases. If the value of a×c is greater than 2.6, this means that the content of trivalent and tetravalent nickel elements in the electrode foil is too high, which affects the content of lithium manganese iron phosphate in the cathode material and thus reduces the capacity of the electrical core and the energy density of the battery.

[0078] Therefore, by controlling the range of values ​​of a×c to meet the range of 0.001≤a×c≤0.092, the present invention can enable the nickel-containing material to perform well in changing the gas generation path of the battery, i.e., reducing the output of hydrogen, while ensuring a better energy density of the battery.

[0079] In the present invention, 0.001 ≤ a × c ≤ 0.092. The value of a × c can be 0.001, 0.002, 0.003, 0.004, 0.005, 0.007, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.092, or any value between 0.001 and 0.092. In some preferred embodiments of the invention, 0.003 ≤ a × c ≤ 0.06.

[0080] In the present invention, the battery comprises a cathode foil, an anode foil, a separator and an electrolyte solution.

[0081] The cathode foil comprises a cathode collector and an active cathode material layer arranged on at least one surface of the cathode collector, the active cathode material layer comprising an active cathode material. In addition to the active cathode material, the active cathode material layer may contain a conductive agent and a binder.

[0082] The conductive material is used to provide electrical conductivity in the electrode, and any conductive material may be used without particular restriction as long as it has suitable electronic conductivity without causing adverse chemical changes in the battery, preferably carbon fibers such as carbon nanofibers, carbon black such as acetylene black and coke black, activated carbon, graphite, mesoporous carbon, fullerenes and carbon materials such as carbon nanotubes.

[0083] The binder is used to improve the adhesion between the particles of the active cathode material and the adhesion between the active cathode material and the collector. Accordingly, a suitable binder for use in the embodiment is a fluoropolyolefin-based binder, and the fluoropolyolefin-based binder may be a fluoropolyolefin-based binder that includes, but is not limited to, polyvinylidene fluoride (PVDF), copolymers of vinylidene fluoride, or modified (e.g., carboxylic acid, acrylic acid, acrylonitrile, and other modifications thereof) derivatives thereof.

[0084] The present invention does not impose any special restrictions on the cathode collector, as long as it is electrically conductive, without causing harmful chemical changes in the battery, and can be made of, for example: stainless steel, aluminum, nickel, titanium, burnt carbon; or aluminum or stainless steel that has been surface-treated with carbon, nickel, titanium, silver and the like.

[0085] In the present invention, the cathode foil can be produced according to conventional methods. For example, the active cathode material, the conductive agent, and the binder are dispersed in a solvent, which can be N-methylpyrrolidone (NMP) or deionized water, to form a homogeneous cathode slurry. The cathode slurry is then applied to the cathode collector, and the cathode foil is obtained after drying, roller pressing, and other processes.

[0086] The anode foil of the present invention comprises an anode collector and an active anode material layer provided on at least one surface of the anode collector, wherein the active anode material layer comprises an active anode material.

[0087] The present invention does not impose any special restrictions on the anode collector, as long as it is electrically conductive, without causing harmful chemical changes in the battery, and can be used, for example: copper, stainless steel, aluminum, nickel, titanium, burnt carbon, or copper or stainless steel, or aluminum-cadmium alloy that has been surface-treated with carbon, nickel, titanium, silver and the like.

[0088] With regard to the active material for the anode, the embodiments of the present invention do not specifically restrict the type of active material for the anode, but can be selected according to the actual requirements. For example, the active anode material can be one or more of the following: natural graphite, synthetic graphite, microcarbon spheres in the middle phase (MCMB), hard carbon, soft carbon, silicon, silicon-carbon complex, SiOm (0 <m<2, z. B. m=1) und Lithiumtitanat mit Spinellstruktur (Li4Ti5O 12 ) act.

[0089] The embodiments of the present invention do not specifically restrict the type of conductive agent and binder in the active anode material layer, but rather allow them to be selected according to actual needs. For example, the conductive agent may be one or more of the following: graphite, superconducting carbon, acetylene black, carbon black, cotinine black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers; and the binder may be one or more of the following: styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl butyral, aqueous acrylic resin, and carboxymethylcellulose. The active anode material layer may also contain a thickening agent, such as carboxymethylcellulose.

[0090] The electrolyte solution of the present invention can be a variety of electrolyte solutions suitable for electrochemical energy storage devices. The electrolyte solution comprises an electrolyte and a solvent, wherein the electrolyte solution typically contains a lithium salt.

[0091] In particular, the lithium salt comprises at least one of the following: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium borate dioxylic acid (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxylic acid phosphate (LiDFOP), and / or lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5 to 5 mol / L.

[0092] In particular, the solvent may be at least one of the following: ethylidene carbonate (EC), propylidene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylenepropylene carbonate (MPC), ethylenepropylene carbonate (EPC), butylidene carbonate (BC), fluorinated ethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), cyclobutane sulfone (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE). Based on the weight of the electrolyte solution, the solvent fraction may be 70 to 98% by weight.

[0093] Furthermore, the electrolyte solution may optionally include an additive. In particular, the additive may, for example, include a film-forming additive for the anode, and furthermore a film-forming additive for the cathode, and may also include an additive that can improve certain properties of the battery, such as an additive to improve the battery's overcharge performance, an additive to improve high-temperature performance, an additive to improve the battery's low-temperature performance, etc.

[0094] The electrochemical device may further include a separator. The separator is arranged between the cathode foil and the anode foil to keep the cathode foil and the anode foil apart and to prevent them from short-circuiting. The separator may be made of various materials suitable for use as insulating membranes for electrochemical energy storage devices according to the prior art. In particular, the separator comprises at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fibers.

[0095] One embodiment of the present invention provides an electronic device comprising a battery as described above. The electrochemical device serves as an energy source for the electronic device.

[0096] An electronic device is any device that can utilize electrical energy and convert it into one or more other forms of energy, such as mechanical energy, thermal energy, light energy, etc., like an electric motor, an electric heater, an electric light source, and the like. Specifically, it can be a mobile device, an electric vehicle, an electric train, a ship, a satellite, an energy storage system, etc. A mobile device can be a mobile phone, a laptop, a drone, a robotic sweeper, an electronic cigarette, etc. An electric vehicle can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.

[0097] For a better understanding of the present invention, the battery provided by the present invention is described below in conjunction with exemplary embodiments, and the scope of protection of the present invention is not limited by the following exemplary embodiments. Exemplary embodiment 1(1) Production of the LMFP cathode material

[0098] Weighing 1 mol of lithium carbonate, 0.6 mol of manganese carbonate, 0.4 mol of diammonium oxalate, 0.1 mol of diammonium hydrogen phosphate according to the molar ratio of the elements Li, Mn, Fe and P in the chemical formula LiMn 0,6 Fe 0,4PO4, deionized water added and mixed, pellet milled to obtain a lithium manganese iron phosphate precursor slurry; then glucose weighed at a mass fraction of 30% and mixed with the lithium manganese iron phosphate precursor slurry, pellet milled for 20 hours, solids content adjusted, and spray dried to obtain dry powder, then pre-filtered to obtain a precursor. The precursor is placed in a tube furnace for calcination, pre-calcined for 300 minutes at a heating rate of 5°C / min to 600°C, then calcined for 720 minutes at a heating rate of 10°C / min to 800°C, and a LiMn agglomerate is obtained. 0,6 Fe 0,4 PO4 after natural cooling. Crushing and grinding of the LiMn agglomerate. 0,6 Fe 0,4 PO4 and sieves after an 8-hour grinding process to obtain the cathode material LiMn 0,6 Fe 0,4 to obtain PO4.

[0099] (2) Production of the cathode foil: Mixing the cathode material of lithium manganese iron phosphate (LiMn0.6Fe0.4PO4) and nickel-based cathode material lithium nickelate (LNO) as the main material in a molar ratio of 17.01:3.79. Mixing the main material with the conductive agent SP and the binder PVDF in NMP according to a mass ratio of 96.5:1.5:2; then applying the mixed cathode slurry uniformly to an aluminum foil with a surface density of 400 g / m². 2 , Drying in a vacuum oven at 100°C to obtain a cathode foil, and cutting the cathode foil into strips; then roller pressing and cutting to obtain the cathode foil.

[0100] (2) Production of the anode foil: Mixing the synthetic graphite, the conductive agent SP and the PVDF adhesive in a mass ratio of 96.4:0.6:3 and dispersing in deionized water to obtain the anode slurry; applying the anode slurry to the copper foil with a surface density of 173 g / m² 2 , Drying at 100 °C in a vacuum environment for 12 hours, followed by cutting and cold pressing with a pressing density of 1.65 g / cm³ 3 , in order to obtain the anode foil.

[0101] (3) Preparation of the electrolyte solution: The electrolyte solution was prepared using EC:EMC=3:7 wt% as the solvent system, 1.15M LiPF6 as the lithium salt and 1% VC (vinylidene carbonate) and 1% MMDS (methanemethanedisulfonic acid dimethylidene ester) as film-forming additives.

[0102] (5) Production of the separator: A PP separator is selected.

[0103] (6) Assembly of the battery, formation and capacity adjustment to form SEI / CEI: Stacking the cathode foil, separator and anode foil in sequence, so that the separator takes on the role of insulation between the cathode and the anode, and then winding them up to obtain the bare electrical core; The bare electrical core is placed in the outer packaging housing and, after drying, injected into the electrolyte solution, with the liquid injection factor being measured at 0.02C to 3.5V / 0.1C to 4.25V in the anode to form a stable SEI. Excess gas is extracted during the second sealing, charged to the upper limit voltage at 0.33C and switched off at 0.05C for a constant voltage charge, and discharged to the lower limit voltage of 2.5V at 0.33C, with the charging and discharging taking place for two cycles so that the cathode side forms a stable CEI. Exemplary embodiment 2-18 and comparative example 1-4

[0104] Exemplary embodiments 2 to 18 and comparative examples 1 to 4 each provide a lithium-ion battery with a manufacturing process similar to that of exemplary embodiment 1, with the difference that the type of cathode material is nickel-based and the ratio of lithium manganese iron phosphate (LiMn₂) is different. 0,6 Fe 0,4 PO4) and nickel-based cathode material used in the production of the cathode foil are listed in Table 1.

[0105] The parameters for the batteries obtained from each embodiment and comparison example were tested as follows:

[0106] The test procedure for the value a is in particular as follows:

[0107] Disassemble the cathode foil when the battery is fully charged at 100% SOC, clean the cathode foil with DMC (dimethyl carbonate) and then dry it for 24 hours at 25°C to obtain the treated cathode foil.

[0108] After receiving the treated cathode foil, it was etched using X-ray photoelectron spectroscopy (XPS) with the NEXSA G2 model. The test beam was set to 400 µm in the instrument's manual control window. Depending on the element being tested, the instrument automatically adjusted the energy range of the test fluence. The etch residence time was 50 ms, the step size 1 eV, the rate 0.7 nm / s, and the etch time 60 seconds. At the end of the test, the instrument automatically output the test results, and the peak area of ​​each valence state was adjusted according to the binding energy.

[0109] A is calculated according to the equation shown in Formula II: a=(SNi4++SNi3+) / Stotal area;

[0110] In Formula II, S denotes Ni 4+ the area of ​​tetravalent nickel determined by XPS testing; S Ni 3+denotes the area of ​​trivalent nickel determined by XPS testing; S Gesamtfläche denotes the sum of the peak areas of the individual valence states of the nickel element obtained by the XPS test.

[0111] See Table 1 for the calculated values ​​of a. 2. The test procedure for the value b is as follows:

[0112] The cathode foil of the fully charged battery (100% SOC) is exchanged in a solution and stored for 48 hours at 60°C, whereby the H + -Content in the solution is measured as m1 in the unit of ppm; then store for 72 hours at 60°C, whereby the H + -Content in the solution is measured as m2 in the unit ppm; where the H + -Growth rate b is calculated according to the equation shown in Formula III: b=(m2−m1) / m1;

[0113] The cathode foil has a test area of ​​147 cm². 2on, in particular three cathode foils of a battery in a fully charged state of 7×7 cm 2 .

[0114] The solution is a mixed solution of ethylene vinyl carbonate EC, methyl ethyl carbonate EMC and lithium perchlorate; in the mixed solution, the concentration of lithium perchlorate is 1 M, the volume ratio of ethylene vinyl carbonate EC to methyl ethyl carbonate EMC is 3:7, and the amount of solution is 20 ml.

[0115] The test procedure for the H+ content in a solution stored for 48 hours includes the following steps:

[0116] Configure triethylamine and EMC to form a 0.05 mol / L triethylamine titrant;

[0117] Mix EC and EMC to a 20 mL mixture in a volume ratio of 3:7 and add 2.13 g of lithium perchlorate to the mixture to obtain a soaking solution;

[0118] Mixing the cathode foil three batteries of 7×7 cm 2In a fully charged state, immerse the cathode foil in the soaking solution for 48 hours at 60°C to obtain a 48-hour soaking solution. Add 10 to 30 drops of methyl red as an indicator to the 48-hour soaking solution. Add the triethylamine titrant dropwise to the 48-hour soaking solution containing the methyl red and record the amount V1 of triethylamine titrant when the 48-hour soaking solution turns orange. Calculate the amount of H + in the solution stored for 48 hours, m1, according to formula IV; m1=M×V1×20010 / m;

[0119] In formula IV, M is the concentration of the titrant in mol / L; V1 is the volume of titrant consumed in mL; m is the mass of the soaking solution in g;

[0120] Similarly, the test procedure for the H+ -Content of the solution stored for 72 hours, the following steps:

[0121] Configure triethylamine and EMC to form a 0.05 mol / L triethylamine titrant;

[0122] Mix EC and EMC to a 20 mL mixture in a volume ratio of 3:7 and add 2.13 g of lithium perchlorate to the mixture to obtain a soaking solution;

[0123] Mixing the cathode foil three batteries of 7×7 cm 2In the fully charged state, immerse the cathode foil in the soaking solution for 48 hours at 60°C to obtain a 72-hour soaking solution. Add 10 to 30 drops of methyl red as an indicator to the 72-hour soaking solution. Add the triethylamine titrant dropwise to the 72-hour soaking solution containing the methyl red and record the amount V2 of triethylamine titrant when the 72-hour soaking solution turns orange. Calculate the amount of H + in the solution stored for 72 hours, m2, according to formula V; m2=M×V2×20010 / m;

[0124] In formula IV, M is the concentration of the titrant in mol / L; V1 is the volume of titrant consumed in mL; m is the mass of the soaking solution in g.

[0125] The H +-The growth rate b is calculated by inserting the values ​​m1 and m2 obtained above into formula III. ③ The test procedure for the value c is as follows:

[0126] The battery was discharged from 0.33C to 2.5V at 25°C, disassembled to obtain a cathode foil and an anode foil, and 2g of cathode powder was obtained from the cathode foil and 2g of anode powder from the anode foil; an inductively coupled plasma (ICP) was used to determine the percentage molar content of the elements Ni and Mn in the cathode powder and anode powder, and the molar percentage of the nickel-based cathode material in the active cathode material, c, was calculated according to the equation shown in Formula VI. c=(Total mol percent of Ni elements in the cathode and anode powders / Total mol percent of Ni and Mn elements in the cathode and anode powders×100%.

[0127] The lithium-ion batteries produced by the above embodiments and comparative examples were tested for their performance, and the specific points and methods were as follows: ① Test procedure for normal temperature cycles:

[0128] Charging to 4.3 V at a temperature of 45°C and 0.33°C, discharging to 2.5 V at 0.33°C, setting the capacity for two cycles, charging to 4.3 V at a temperature of 45°C with a constant current of 1 C and constant voltage, discharging to 2.5 V with a constant current of 1 C. At the end of 200 cycles, the discharge capacity of the third cycle is recorded as C1 and the discharge capacity of the 200th cycle as C2, and the capacity maintenance rate of 200 cycles = (C2 / C1) × 100%. 2. Test procedure for the DCR growth rate:

[0129] Charge the battery at 45°C at 0.33C to 4.3V, discharge the battery at 0.33C to 2.5V and adjust the capacity for two cycles; charge the battery at 45°C with a constant current of 0.33C and constant voltage to 4.3V and discharge the battery at 0.33C to regulate the charge to 80% SOC, let it rest for two hours, then discharge the battery at 1C for 18s and measure the DCR at 1C and record it as R0; discharge the battery at 45°C at 0.33C to 2.5V; and further charge the battery at 45°C with 1C constant current and constant voltage to 4.3V, discharge with 1C constant current to 2.5V, and repeat the 1C / 1C charge and discharge cycle after 200 cycles; Recharging the battery at 0.33C to 4.3V and discharging at 0.33C to 2.5V at a temperature of 45°C, setting the capacity for two cycles;Discharge the battery at 0.33C to regulate the charge to 80% SOC and let it stand for two hours, discharge at 1C for 18S to measure the 1C DCR recorded as R1, and calculate the growth rate of the DCR for 200 cycles = [(R1-R0) / R0] × 100%.;

[0130] The test results are listed in Table 1. Table 1 a b c a×c (a xc) / b Nickel-based cathode material Molar ratio of lithium manganese iron phosphate and nickel-based cathode material Capacity maintenance rate after 200 cycles DCR growth rate Example of implementation 11 15,21% 0,063 18,22% 3,0277 0,440 Lithium phosphate 17,01:3,79 96,30% 9,86% Example of implementation 12 1,02% 0,034 29,90% 9,0030 0,090 Lithium phosphate 14,58:6,22 95,80% 9,83% Example of implementation 13 19,93% 0,051 5,24% 3,0104 0,205 Lithium phosphate 19,71:1,09 96,58% 9,85% Example of implementation 14 19,98% 0,021 30% 0,0599 2,854 Lithium phosphate 14,56:6,24 96,92% 9,98% Example of implementation 15 5,66% 0,148 5,54% 0,0037 0,025 Lithium phosphate 19,44:1,36 96,02% 9,85% Example of implementation 16 1,34% 0,070 13,41% 0,0018 0,026 Lithium phosphate 18,01:2,79 95,12% 9,80% Example of implementation 17 20,08% 0,136 30,38% 0,0610 0,449 Lithium phosphate 14,48:6,32 94,93% 9,88% Example of implementation 18 0,98% 0,151 25,53% 0,0025 0,017 Lithium phosphate 15,49:5,31 95,03% 9,98% Example of implementation 19 10,66% 0,018 4,95% 0,0053 0,293 Lithium phosphate 19,77:1,03 94,62% 9,97% Example of implementation 10 1,45% 0,150 21,39% 0,0031 0,021 Lithium phosphate 16,35:4,45 94,56% 9,99% Example of implementation 11 19,76% 0,020 29,81% 0,0589 2,945 Lithium phosphate 14,6:6,2 94,22% 10,01% Example of implementation 12 0,68% 0,178 33,56% 0,0023 0,013 Lithium phosphate 13,82:6,98 93,99% 10,02 % Example of implementation 13 0,40% 0,158 32,26% 0,0013 0,008 Lithium phosphate 14,09:6,71 94,09% 10,05% Example of implementation 114 22,76% 0,012 37,88% 0,0862 7,185 Lithium phosphate 12,92:7,88 93,82% 10,09% Example of implementation 15 22,75% 0,011 40,00% 0,0910 8,273 Lithium phosphate 12,48:8,32 93,41% 10,11% Example of implementation 16 0,19% 0,009 47,36% 0,0009 0,100 Lithium phosphate 10,95:9,85 92,21% 10,19% Example of implementation 17 20,29% 0,019 45,67% 0,0927 4,877 Lithium phosphate 11,3:9,5 91,81% 10,25% Example of implementation 18 15,19% 0,061 18,03% 0,0274 0,449 LiNi 0.92 Co 0.03 Mr 0.05 O2 17,05:3,75 96,33% 9,87% Comparative example 1 0,38% 0,173 31,20% 0,0012 0,007 Lithium phosphate 14,31:6,49 88,99% 14,23% Comparative example 2 23,00% 0,011 39,76% 0,0914 8,313 Lithium phosphate 12,53:8,27 87,01 % 14,66% Comparative example 3 0,36% 0,170 31,11% 0,0011 0,007 Li Ni 0.92 Co 0.03 Mr 0.05 O2 14,33:6,47 88,93% 14,13% Comparative example 4 23,12% 0,011 39,86% 0,0922 8,378 LiNi 0.92 C 00.03 M N 0.05 O2 12,51:8,29 87,62% 14,56%

[0131] For the lithium-ion batteries produced in each of the embodiments of the present invention, the 200 cls cycle capacity maintenance rate is ≥91.81% and the DCR growth rate is <10.25%, which shows that the lithium-ion batteries of the present invention have reduced gas generation, which in turn reduces the internal resistance of the batteries and improves the cycle performance of the batteries.

[0132] As can be seen from embodiments 1 to 5 and embodiments 10 to 11 in combination with the data from embodiments 6 to 9, embodiments 12 to 18 and comparative examples 1 to 4, the lithium-ion battery has a lower internal resistance and a relatively better cycle performance when a, b, c and a×c satisfy the range of preferred parameters defined by the present invention.

[0133] As can be seen from embodiments 1 to 5 in combination with embodiments 6 to 9, the lithium-ion battery has a lower internal resistance and a relatively higher cycle life when the battery meets a value of 0.008<(a×c) / b≤8.290.

[0134] As can be seen from the results of comparative examples 1 to 4, even when a, b, c and a×c meet the parameter ranges limited by the present invention, the lithium-ion battery exhibits a higher internal resistance and a lower cycle life if the battery does not meet the range of 0.008< (a×c) / b≤8.290.

[0135] The foregoing is only a preferred embodiment of the present invention, and it should be noted that for a person of ordinary knowledge in the field, a number of improvements and embodiments can be made without derogation from the principles of the present invention, and these improvements and embodiments should also be considered as being within the scope of protection of the present invention.

[0136] The present invention relates to the technical field of lithium-ion batteries, in particular a battery. In the present invention, by controlling the percentage of the total molar amount of trivalent and tetravalent nickel in the lithium-ion battery relative to the total molar amount of nickel in the nickel-based cathode material, the molar ratio of the nickel-based cathode material to the active cathode material, and the growth rate of H+ in the cathode foil, the amount of gas produced by the battery can be significantly reduced, and close contact between the battery's electrode foil and the separator can be ensured, thereby reducing the battery's internal resistance and improving its cycle performance.

Claims

[1] Battery, characterized by , that it comprises a cathode foil, wherein the cathode foil comprises an active cathode material, wherein the active cathode material comprises a lithium manganese iron phosphate material and a nickel-based cathode material, wherein the nickel-based cathode material contains trivalent nickel elements and tetravalent nickel elements, wherein a molar ratio of the nickel-based cathode material to the active cathode material c is, wherein, when the battery is in a state of 100% SOC, a percentage of the total molar amount of the trivalent nickel elements and the tetravalent nickel elements to the total molar amount of the nickel elements in the nickel-based cathode material a is, wherein an H + -growth rate of the cathode foil b is, where a, c and b satisfy a relational equation represented in Formula I: 0.008<(a×c) / b≤8.

290. [2] Battery according to claim 1, characterized by, that 0.025≤(a×c) / b≤2.

860. [3] Battery according to claim 1, characterized by , that 0.3%≤a≤23%. [4] Battery according to claim 1, characterized by , that 1%≤a≤20%. [5] Battery according to claim 1, characterized by , that 0.01≤b≤0.

18. [6] Battery according to claim 1, characterized by , that 0.02≤b≤0.

15. [7] Battery according to claim 1, characterized by , that 0.5%≤c≤40%. [8] Battery according to claim 1, characterized by , that 5%≤c≤30%. [9] Battery according to claim 1, characterized by , that 0.001≤a×c≤0.

092. [10] Battery according to claim 1, characterized by , that 0.003≤a×c≤0.

06. [11] Battery according to claim 1, characterized by that the nickel-based cathode material is selected from one or more lithium-nickel-oxygen cathode materials or nickel-containing ternary cathode materials. [12] Battery according to claim 11, characterized by, that the nickel-containing ternary cathode material is selected from a ternary cathode material made of nickel-cobalt-manganese, wherein the ternary nickel-cobalt-manganese material is LiNi x Co y Mn 1-x-y O2 is, where 0.9 <x< 1 und 0<y<0,1 ist. [13] Battery according to claim 1, characterized by , that the molar ratio between the trivalent nickel element and the tetravalent nickel element is 1:10 to 6:

10. [14] Battery according to claim 1, characterized by , that the battery further comprises an anode foil, a separator and an electrolyte solution; wherein the anode foil comprises an active anode material, wherein the active anode material consists of one or more of natural graphite, artificial graphite, carbon microspheres in the intermediate phase, hard carbon, soft carbon, silicon, silicon-carbon complex, SiO₂ m , where 0 <m<2, und Li4Ti5O 12 selected; where the separator is selected from PP, PE or PP / PF; wherein the electrolyte solution comprises a lithium salt and a solvent, wherein the lithium salt is selected from a composition of one or more of lithium hexafluorophosphate, lithium difluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium tetrafluorooxalate phosphate or lithium bis(boronyl)oxalate, and wherein the solvent is selected from a composition of one or more of vinyl carbonate, methoxy carbonate, diethyl carbonate, propylene carbonate or dimethyl carbonate.