Negative terminal, secondary battery with negative terminal and power-consuming device

Abstract

A negative pole piece comprising a current collector of the negative electrode and a layer of active material of the negative electrode arranged on at least one surface of the current collector of the negative electrode, wherein the layer of active material of the negative electrode comprises an active material of the negative electrode, characterized in that the active material of the negative electrode comprises a carbon material and a silicon oxide, and wherein the active material of the negative electrode also contains aluminum and sulfur elements, wherein the negative pole piece satisfies the relational equation shown in equation (1) and equation (2) or the following equations (1) and (2): − 1.75 ≤ lg ( W Al × W s / α ) ≤ 1.05, 0.2 ≤ lg (W s × R ) + 0.15 × R ≤ 2.5, and where W Al and W SThe mass fractions of the aluminum element and the sulfur element in the active material of the negative electrode are both in ppm; and where α is the contact angle between the layer of active material of the negative electrode and a solvent in ° and the solvent is a mixed solution of / with vinyl carbonate and methyl ethyl carbonate in a weight ratio of 1:1; and where R is the ion transport impedance or ion transmission impedance of the negative pole piece in Ω.

Description

Technical field

[0001] The present invention relates to the technical field of batteries, in particular a negative pole piece, a secondary battery with the negative pole piece and a power-consuming device. State of the art

[0002] With the popularity and development of electric vehicles, improving the energy density of batteries, the core component of electric vehicles, is receiving widespread attention as an important way to solve the problem of "range anxiety".

[0003] The current carbon material used for negative electrodes has a low theoretical lithium storage capacity, which severely limits further improvements in the energy density of lithium-ion batteries. Silicon has a theoretical specific capacity ten times higher than carbon. Therefore, to meet the demand for batteries with higher energy density, silicon-based negative electrodes have come into focus.

[0004] Among the numerous silicon and silicon compounds, silicon oxides exhibit a relatively high theoretical capacity and are good materials for negative electrodes in lithium-ion batteries. However, the electrical conductivity of silicon oxide is poor, and the expansion and contraction of the silicon oxide during the lithium embedding and removal process is significant when silicon oxide is used as the negative electrode material. This leads to damage of the silicon oxide during charging and discharging, and the problem of volumetric expansion results in a susceptibility to cracking of silicon-based negative electrodes during the cycling process, poor cycle performance, and a low capacity retention rate at low temperatures. Therefore, the widespread use of silicon-based negative electrodes is limited. Content of the invention

[0005] One purpose of the present invention is to overcome the shortcomings of the prior art and to provide a negative terminal, a secondary battery with the negative terminal, and a current-consuming device, wherein the active material of the negative electrode of the negative terminal comprises a carbon material and a silicon oxide, as well as a specific amount of an aluminum element and a sulfur element. The use of the negative terminal of the present invention in the secondary battery is able to significantly reduce the cracking of the negative terminal during the charging and discharging process and thereby improve the cycle performance of the lithium-ion battery. Furthermore, the capacity retention rate of the battery during low-temperature cycles is also improved. The invention is defined by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0006] To achieve the above-mentioned purpose, in a first aspect of the present invention, a negative pole piece is provided comprising a negative electrode current collector and a layer of active material of the negative electrode arranged on at least one surface of the negative electrode current collector, wherein the layer of active material of the negative electrode comprises an active material of the negative electrode. and wherein the active material of the negative electrode comprises a carbon material and a silicon oxide, and wherein the active material of the negative electrode also contains aluminium and sulfur elements, wherein the negative pole piece satisfies the relational equation shown in equation (1) and equation (2): −2≤lg(WAl×Ws / α)≤1.05, 0.2≤lg(Ws×R)+0.15×R≤2.5, and where W Al and W SThe mass fractions of the aluminum element and the sulfur element in the active material of the negative electrode are both in ppm; and where α is the contact angle between the layer of active material of the negative electrode and the solvent in ° and the solvent is a mixed solution of vinyl carbonate and methyl ethyl carbonate in a weight ratio of 1:1; and where R is the ion transmission impedance of the negative pole piece in Ω.

[0007] In a preferred embodiment of the present invention, the negative pole piece satisfies the relational equation described in equation (3): 0.4≤lg(WAl×Ws / α)≤0.95,

[0008] In a preferred embodiment of the present invention, the negative pole piece satisfies the relational equation described in equation (4): 1.25≤lg(Ws×R)+0.15×R≤2.0,

[0009] In a preferred embodiment of the present invention, the W Al -value in the range of 0.5 to 12 ppm; and / or the W S -Value in the range of 1.0 to 22 ppm.

[0010] In a more preferred embodiment of the present invention, the W Al -value in the range of 5.0 to 10.6 ppm; and / or the W S -Value in the range of 4.5 to 21.5 ppm.

[0011] In a preferred embodiment of the present invention, the α value lies in the range of 20 to 50°.

[0012] In a preferred embodiment of the present invention, the α value lies in the range of 22 to 35°.

[0013] In a preferred embodiment of the present invention, the R-value is in the range of 0.05 to 3 Ω.

[0014] In a preferred embodiment of the present invention, the R-value is in the range of 0.2 to 2 Ω.

[0015] In a preferred embodiment of the present invention, the weight fraction of silicon oxide is in the range of 1 to 10 wt.%, based on the total weight of the carbon material and the silicon oxide.

[0016] In a second aspect of the present invention, the present invention provides a secondary battery comprising a positive pole piece, a negative pole piece and an electrolyte solution, wherein the negative pole piece is the above negative pole piece.

[0017] In a third aspect of the present invention, the present invention provides a power-consuming device comprising the secondary battery.

[0018] The present invention has the following advantages: The active material of the negative electrode in the negative terminal of the present invention contains a carbon material and a silicon oxide and also a certain amount of Al and S. The use of the negative terminal of the present invention in the secondary battery is able to significantly reduce the cracking of the negative terminal during the charging and discharging process and thereby improve the cycle performance of the battery. Furthermore, the capacity retention rate of the battery during low-temperature cycles is also improved. Brief description of the drawing Fig. Figure 1 shows a scanning electron micrograph of the negative pole piece in comparative example 1 of the present invention after 200 cycles at 45°C. Detailed descriptions

[0019] The technical solution in the embodiments of the present invention is explained clearly and completely below, so that the objective, the technical solutions, and the advantages of the embodiments of the present invention become clearer. Obviously, the described embodiments do not represent all embodiments, but only a subset of the embodiments of the present invention. All other embodiments that a person skilled in the art in this field could obtain from the embodiments in the present invention without any creative work should be considered to be covered by the scope of protection of the present invention.

[0020] The present invention includes, among the technical features described in an open manner, a closed technical solution with the listed features, and also a disclosed technical solution with the listed features.

[0021] Within the scope of the present invention, a numerical interval is considered continuous within said numerical interval unless otherwise specified, and includes a minimum and a maximum value of the range, as well as each of the values ​​between these minimum and maximum values. If the range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. If several ranges are specified to describe a feature or property, the ranges may also be combined. In other words, unless otherwise specified, all ranges disclosed herein are to be understood as encompassing all subranges contained therein.

[0022] The specific dispersion and mixing treatments are not specifically limited within the scope of the present invention.

[0023] The reagents or instruments used without manufacturer information are all commercially available products on the market.

[0024] To solve the problems of existing technology, in which the silicon-based negative electrode material is prone to cracking during the cycle, has poor cycle performance and a low capacity retention rate at low temperatures, an embodiment of the present invention provides a negative pole piece comprising a negative electrode current collector and a layer of negative electrode active material arranged on at least one surface of the negative electrode current collector, wherein the layer of negative electrode active material comprises a negative electrode active material. and wherein the active material of the negative electrode comprises a carbon material and a silicon oxide, and wherein the active material of the negative electrode also contains aluminium and sulfur elements, wherein the negative pole piece satisfies the relational equation shown in equation (1) and equation (2): −2≤lg(WAl×Ws / α)≤1.05, 0.2≤lg(Ws×R)+0.15×R≤2.5, and where W Al and W S The mass fractions of the aluminum element and the sulfur element in the active material of the negative electrode are both in ppm; and where α is the contact angle between the layer of active material of the negative electrode and the solvent in ° and the solvent is a mixed solution of vinyl carbonate and methyl ethyl carbonate in a weight ratio of 1:1; and where R is the ion transmission impedance of the negative pole piece in Ω.

[0025] In the present invention, by comprehensive control of the content of aluminum and sulfur elements in the active material of the negative electrode and the contact angle of the layer of active material of the negative electrode, as well as the ion transport impedance of the negative pole piece, the crack condition of the resulting negative pole piece is significantly improved during the charging and discharging process, and the negative pole piece is applied to the secondary battery, thereby also improving the cycle performance of the battery, in particular the capacity retention rate at a low temperature.

[0026] In the active material of the negative electrode of the present invention, a specific amount of Al, S contributes to improving the cycle performance. The active material of the negative electrode with silicon oxide contains a specific amount of Al, and the number of electrons in the outer layer of Al is less than the number of electrons in the outer layer of silicon, thus creating electronic vacancies. The creation of vacancies can improve the conductivity of the silicon material, and the conductivity of silicon oxide is an important factor that limits its cycles; therefore, a specific amount of Al can improve the cycle performance of the material to a certain extent.The lithium sulfide, which is formed by the reaction between S and lithium ions in the active material of the negative electrode, can play a buffering role within the particles and thus improve the crack condition in the negative pole piece, as well as the cycle performance.

[0027] Al and S can be introduced either by the production of the active material of the negative electrode, e.g. by adding aluminum oxide during the production of the precursor of the silicon dioxide-oxygen material; or by separately adding the corresponding elements during the production of the active material of the negative electrode.

[0028] The contact angle is the angle between the liquid, solid, and gaseous phases, and the contact angle in the present invention is the contact angle between the active material layer of the negative electrode and the solvent mixture of vinyl carbonate and methyl ethyl carbonate. The electrolyte solution of the lithium-ion battery generally contains a lithium salt, a solvent, and an additive, and the vinyl carbonate and methyl ethyl carbonate used to test the contact angle in the present invention are common solvents in the electrolyte solution. When the contact angle decreases, the wetting rate of the electrolyte solution on the electrode increases, the electrolyte solution wets the electrode more readily, and the distribution uniformity of the electrolyte solution throughout the battery cell structure is higher.Increasing the wetting rate not only improves the liquid phase transfer rate of lithium ions and the low-temperature capacity maintenance rate of the battery, but also ensures that the terminal can fully absorb the electrolyte solution. This mitigates the polarization rise and lithium precipitation caused by insufficient liquid absorption in the late stages of the cycle, thus extending the cycle life. If the contact angle is too small, the compression density of the negative terminal may be low, resulting in insufficient battery energy density.

[0029] Considering that the contact angle, together with W Al and W S Since the contact angle has an influence on the cycle performance and the expansion of the battery, in the present invention it is regulated in combination with the content of Al and S to W Al , W Sand to control α so that they satisfy the range of equation (1), which can significantly improve the crack condition and cycle performance of the negative pole piece.

[0030] The ion transport impedance reflects the transport rate of electrolyte ions in the electrode pores. Generally, the transport rate of electrolyte ions is relatively higher when the ion transport impedance is low, contributing to a higher capacity retention rate of the battery under low-temperature conditions. However, the ion transport impedance should not be too low, and the ion transport impedance of the negative electrode is influenced by a variety of factors, such as the pore structure of the active material layer of the negative electrode, its porosity, the morphological properties of the active material, and the like.To achieve a lower ion transport impedance, the number of active reaction sites in the negative terminal can increase, and more active materials are used to embed lithium ions. This consumes a large amount of active lithium and leads to expansion and contraction of the terminal, causing microcracks during cycling and thus degrading the battery's cycle performance.

[0031] The sulfur content in the active material of the negative electrode influences the ion transport impedance of the negative pole to some extent. The sulfur in the active material of the negative electrode can provide additional reaction sites by forming sulfides through chemical reactions with lithium ions, thereby increasing the adsorption and storage capacity of lithium ions. This means that more lithium ions can participate in the reaction and be transported through the active material of the negative electrode during charging and discharging, thus reducing the ion transport impedance to a certain degree. However, with increasing sulfur content, excessive sulfide aggregation or the formation of sulfides with oversized particles can occur, increasing the length of the ion transport path and negatively impacting the ion transport impedance.

[0032] Therefore, in the negative terminal of the present invention, the low-temperature capacity retention rate, crack resistance, and cycle performance of the battery are simultaneously improved by W S and R are regulated so that they satisfy the range of equation (2).

[0033] In the present invention, the value of lg(W) can be Al ×W S / α) for example - 1.9, -1.8, -1.7, -1.5, -1.0, -0.5, 0, 0.1, 0.3, 0.5, 0.8, 0.9.

[0034] In the present invention, the value of lg(W) can be S xR)+0.15xR, for example, 0.2, 0.5, 0.8, 1.0, 1.2, 1.5, 1.7, 1.9, 2.0, 2.3, 2.5.

[0035] In one embodiment, the negative pole piece satisfies the relational equation described in equation (3): 0.4≤lg(WAl×Ws / α)≤0.95,

[0036] In one embodiment, the negative pole piece satisfies the relational equation described in equation (4): 1.25≤lg(Ws×R)+0.15×R≤2.0,

[0037] If the negative terminal also satisfies the relational equation described in equation (3) and / or equation (4), there will be less cracking of the negative terminal after the charging and discharging process, and the battery will have a higher capacity retention rate and a longer cycle life during the low-temperature cycle process.

[0038] In one embodiment, the W Al -value in the range of 0.5 to 12 ppm; and / or the W S -Value in the range of 1.0 to 22 ppm.

[0039] In an even more preferred embodiment, the W Al -value in the range of 5.0 to 10.6 ppm; and / or the W S -Value in the range of 4.5 to 21.5 ppm.

[0040] For example, the W Al -Value 0.5 ppm, 1.0 ppm, 1.5 ppm, 2.0 ppm, 3.0 ppm, 5.0 ppm, 8.0 ppm, 10.0 ppm, 11.0 ppm, 12.0 ppm.

[0041] For example, the WS -Value 1.0 ppm, 1.5 ppm, 2.0 ppm, 3.0 ppm, 5.0 ppm, 10.0 ppm, 15.0 ppm, 18.0 ppm, 20.0 ppm, 22.0 ppm.

[0042] As mentioned previously, a certain amount of aluminum and sulfur contributes to improving the performance of the negative electrode; however, the aluminum and sulfur content should not be too high. The presence of aluminum leads to the formation of vacancies, and the reactivity at these vacancies is high. If the number of vacancies is too high, this is also detrimental to improving the battery's cycle performance. In the active material of the negative electrode, sulfur is an impurity that undergoes side reactions with the electrolyte solution and can produce negative effects, such as a reduction in the battery's capacity retention rate at low temperatures. Al and W SWithin the aforementioned ranges, the overall performance of the negative pole piece is relatively better.

[0043] Regarding the detection method of W Al and W S The present invention is not limited, and the person skilled in the art in this field can W Al and W S detect using conventional technical means, and the following inductively coupled plasma emission spectrometry (ICP-OES) method can be used for measurement as an example.

[0044] In one embodiment, α lies in the range of 20 to 50°, for example α is 20°, 22°, 23°, 25°, 28°, 30°, 35°, 40°, 45°, 50°.

[0045] In a preferred embodiment, the α value lies in the range of 22 to 35°.

[0046] If α is in the range of 22 to 35°, the battery using the negative terminal has a good cycle life, a good crack condition of the negative terminal, and a relatively higher capacity retention rate at low temperatures.

[0047] The method for measuring the contact angle is not limited by the present invention, and the person skilled in the art in this field can measure the contact angle between the layer of active material of the negative electrode and the solvent mixture of vinyl carbonate and methyl ethyl carbonate using the usual technical means, and by way of example a contact angle tester can be used to measure the contact angle.

[0048] In one embodiment, the R-value is in the range of 0.05 to 3 Ω. For example, the R-value is 0.05 Ω, 0.08 Ω, 0.10 Ω, 0.15 Ω, 0.20 Ω, 0.50 Ω, 1.0 Ω, 1.5 Ω, 2.0 Ω, 2.5 Ω, 2.7 Ω, 2.80 Ω, 2.85 Ω, 2.90 Ω and 3.0 Ω.

[0049] In a preferred embodiment, the R-value is in the range of 0.2 to 2 Ω.

[0050] In the present invention, the cycle performance and the crack condition of the negative pole piece are relatively better when the R-value is in the range of 0.05 to 3 Ω and particularly in the range of 0.2 to 2 Ω.

[0051] The ion transport impedance of the negative terminal can be tested using the following method: two identical negative terminals are used to create a symmetrical battery, and the electrochemical impedance spectra (EIS) of the symmetrical battery are collected using an electrochemical workstation. The AC impedance spectra are obtained from the EIS test. In combination with an equivalent circuit and an impedance decomposition model, an in-depth analysis of the impedance composition is performed to obtain a Nyquist plot and a Bode plot. Z-view or EC-Lab software is then used for fitting, and the degree of overlap between the simulated and measured plots is increased by adjusting the value of each impedance. The ion transport impedance is then calculated according to the following formula: Z'ω→0 = Rsol - Rion / 3;where Rion is the ion transport impedance in the present application, Rsol is the ohmic impedance, and Z'ω→0 is the hybrid impedance, and the values ​​of Rsol and Z'ω→0 can be obtained from the Nyquist diagram of EIS (see the test method in this literature: Ogihara N, Kawauchi S, Okuda C, et al. Theoretical and experimental analysis of porous electrodes for lithium-ion batteries by electrochemical impedance spectroscopy using a symmetric battery [J]. (Journal of The Electrochemical Society, 2012, 159(7): A1034.);

[0052] In one embodiment, the weight fraction of silicon oxide relative to the total amount of carbon material and silicon oxide is 1 to 10 wt.%, which can be, for example, 1 wt.%, 2 wt.%, 3 wt.%, 5 wt.%, 8 wt.%, 10 wt.%.

[0053] In one embodiment, the carbon material comprises at least one of the following substances: graphite, soft carbon, or hard carbon. Graphite is preferred as the carbon material. The graphite refers to a material with a graphite-like crystal structure, e.g., natural graphite, synthetic graphite, carbon microspheres in the intermediate phase, and the like.

[0054] In one embodiment, the silicon oxide comprises SiO x , where 0 <x<2.

[0055] A person skilled in this field can investigate the weight fraction of carbon material and silicon oxide in the active material of the negative electrode using conventional technical means. For example, the weight of the carbon material contained in the active material of the negative electrode can be measured by combustion, the proportion of silicon can be determined by optical ICP emission spectroscopy and ICP mass spectrometry, and the combination state of silicon and oxygen (i.e., the value of x in SiO₂) can be determined by X-ray photoelectron spectroscopy (XPS or ESCA). x ) checked to specify the composition and weight of the silicon oxide; the weight fraction of the silicon oxide relative to the total amount of the carbon material and the silicon oxide can be calculated based on the weight of the carbon material and the silicon oxide.

[0056] The method for producing an active material of the negative electrode in the present invention is not particularly restricted, and the person skilled in the art in this field can use conventional means to produce the active material of the negative electrode.

[0057] For example, the negative pole piece is manufactured as follows: Mixing a carbon source precursor and a doping element precursor (if present) and reacting at 120-200°C for 5-10h to obtain the modified carbon source precursor; The resulting modified carbon source precursor is graphitized under inert gas protection at a temperature of 2200-3000°C for 2-10 h, cooled and crushed to obtain a carbon material containing the doping element; Silicon, silicon dioxide, and dopants (if present) are mixed, and the mixture is ball-milled at a speed of 400–800 rpm for 2–10 hours; the mixture is then heated and gasified under evacuated conditions at a temperature of 700–1200 °C for 1–6 hours; after cooling, the mixture is pulverized and sorted to separate the intermediate product (SiO₂). x with dopants). Under the protection of an inert gas, a gas-phase deposition is carried out by introducing carbon-containing gas, and the gas-phase deposition temperature is 700-1000°C, whereby a carbon layer forms on the surface of the intermediate product; thus, a silicon oxide material with dopants is produced, the inner core being made of SiO₂. xconsists of doping elements and the outer layer is covered with a carbon layer; The carbon material containing the dopant and the silicon oxide material containing the dopant are mixed to obtain the active material of the negative electrode.

[0058] For the negative terminal, there are no special restrictions in the present invention, as long as it has high conductivity without causing adverse chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, burnt carbon, and copper or stainless steel that has undergone a surface treatment with one of the elements carbon, nickel, titanium or silver, etc., or an aluminum-cadmium alloy can be used.

[0059] The layer of active material of the negative electrode of the negative pole piece may, in addition to the active material of the negative electrode, also contain a conductive agent and a binder.

[0060] The conductive agent plays a role in improving the conductivity of the active material layer of the negative electrode, and there is no particular restriction on the conductive agent in the present invention; for example, carbon powders such as carbon black, acetylene black, ketjen black, sewer black, furnace black, lamp black or thermal cracking black, graphite powders such as natural graphite or synthetic graphite, conductive fibers such as carbon fiber or metal fiber, conductive whiskers such as zinc oxide whiskers or potassium titanate whiskers, etc., can be used.

[0061] The binder serves to improve the bond between the conductive medium, the active material of the negative electrode, and the current collector of the negative electrode. The present invention has no particular restrictions regarding the binder; for example, a polymeric material such as a fluoropolymer-based binder, a rubber-based binder, a cellulose-based binder, a polyol-based binder, a polyolefin-based binder, a polyimide-based binder, a polyester-based binder, or a silane-based binder can be used.

[0062] Furthermore, a thickening agent can be introduced into the active material layer of the negative electrode, and this thickening agent can be carboxymethylcellulose.

[0063] It should be noted that the method for producing a negative pole piece in the present invention is not particularly limited, and a person skilled in the art can produce it as a negative pole piece according to the conventions.

[0064] For example, the negative pole piece is manufactured as follows: A suspension of the negative electrode is prepared by dissolving or dispersing the active material of the negative electrode, as well as the optional binder and conductive agent in a solvent; The negative electrode slurry can be applied to the negative electrode current collector, and then it is rolled or dried to obtain a negative pole piece; or alternatively The negative electrode slurry can be poured onto a separate support, and then the film layer separated from the support is laminated onto the current collector of the negative electrode to produce the negative pole piece.

[0065] Optionally, the sulfur-containing substance comprises at least one of sulfur monomer, ammonium persulfate, thioacetamide, thiourea and sodium sulfate; and the aluminium-containing substance comprises at least one of aluminium monomer, aluminium fluoride, aluminium chloride, aluminium nitrate and aluminium sol.

[0066] One embodiment of the present invention provides a secondary battery comprising a positive pole piece, a negative pole piece and an electrolyte solution, wherein the negative pole piece is the negative pole piece described above.

[0067] The positive pole piece of the present invention comprises a current collector of the positive electrode and a layer of active material of the positive electrode, which is arranged on at least one surface of the current collector of the positive electrode, wherein the layer of active material of the positive electrode comprises an active material of the positive electrode, and wherein it may further comprise a conductive agent and / or a binder.

[0068] For the current collector of the positive electrode, there are no particular restrictions in the present invention, as long as it has high conductivity without causing adverse chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, burnt carbon, and copper or stainless steel that has undergone a surface treatment with one of the elements carbon, nickel, titanium, or silver, etc., or an aluminum-cadmium alloy can be used. The current collector of the positive electrode can be identical to or different from the current collector of the negative electrode in the present invention.

[0069] The active material of the positive electrode is a compound capable of reversibly embedding and disembedding lithium. For example, the active material of the positive electrode can comprise a lithium composite metal oxide, wherein the lithium composite metal oxide comprises lithium and at least one metal from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb, and Bi, preferably at least one from Co, Ni, and Mn. In particular, the active material of the positive electrode can comprise at least one of Li(Ni) 0,6 Mn 0,2 Co 0,2 )O2, Li(Ni 0,7 Mn 0,2 Co 0,10 )O2, Li(Ni 0,8 Mn 0,1 Co 0,1 )O2, Li(Ni 0,8 Co 0,15 Al0, 05 )O2, Li(Ni 0,86 Mn 0,07 Co 0,05 Al 0,02 )O2, Li(Ni 0,9 Mn 0,05 Co 0,05 )O2 include.

[0070] It should be noted that the method for producing a positive pole piece in the present invention is not particularly limited, and a person skilled in the art can produce it as a positive pole piece according to the conventions.

[0071] The electrolyte solution of the present invention can be various electrolyte solutions suitable for the electrochemical energy storage device. The electrolyte solution comprises an electrolyte and a solvent, wherein the electrolyte typically comprises a lithium salt, and in particular, the lithium salt can be an inorganic lithium salt and / or an organic lithium salt. The solvent in the electrolyte solution is typically a non-aqueous solvent, and in particular, the solvent comprises at least one of the following substances: vinyl carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, or halogenated derivatives thereof.

[0072] The secondary battery may further include a diaphragm located between the positive and negative terminals to separate them and prevent them from coming into contact and causing a short circuit. The diaphragm may be made of various materials suitable for use as an insulating membrane for the electrochemical energy storage device. In particular, the diaphragm may include at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fiber.

[0073] One embodiment of the present invention provides a power-consuming device that includes the secondary battery. The secondary battery serves as a power supply for the power-consuming device.

[0074] The term "electrical device" refers to 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. Examples include an electric motor, an electric heater, an electric light source, and the like. Specifically, it can refer to a mobile device, an electric vehicle, an electric train, a ship, a satellite, an energy storage system, etc. A mobile device could be a mobile phone, a laptop, a drone, a robotic sweeper, an electronic cigarette, etc. An electric vehicle could 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.

[0075] The present invention is explained in more detail below in connection with specific embodiments: In the specific embodiments of the present invention, W Al and W S detected as follows: After disassembling the secondary battery to remove the negative electrode, a 5 cm × 5 cm negative electrode is cut out. All materials except the current collector of the negative electrode are scraped off. 1.0000 g of the sample is weighed with an accuracy of 0.0001 g and placed in a dry, clean, and unadulterated polytetrafluoroethylene beaker. A small amount of ultrapure water is added to moisten the powder, followed by 15 ml of aqua regia. The beaker is placed on a hot plate and heated at 230°C for 25 minutes. The inside of the beaker is then rinsed with ultrapure water so that the sample adhering to the inner wall flows to the bottom. The beaker is then heated for another 20 minutes. After filtration with quantitative filter paper, the volume is adjusted to 50 mL with purified water. A blank sample is prepared using the same method.Finally, the test is performed using an inductively coupled plasma emission spectrometer, and the test instrument can be a Perkin-Elmer Optima 8000 in ppm.

[0076] In the specific embodiments of the present invention, the contact angle α is detected as follows: Using vinyl carbonate and methyl ethyl carbonate (weight ratio 1:1) as solvents, the contact angle test is performed using a JC2000D2M contact angle tester manufactured by Shanghai Zhongchen Digital Technology Equipment GmbH. The specific test conditions are as follows: the negative electrode is held at 25°C for 30 minutes. Then, the solvent is applied dropwise to the surface of the active material layer of the negative electrode at various locations (one drop at each location). A contact angle tester is used to observe the point at which the drops fully contact the active material layer of the negative electrode. The contact angle at this point is calculated, and the average value is determined based on the test results from the various locations. This average represents the contact angle of the active material layer of the negative electrode.

[0077] In the specific embodiments of the present invention, the ion transport impedance (R) is detected as follows: Fabrication of a symmetrical battery using two identical negative terminals, measurement of the AC impedance of the symmetrical battery using an electrochemical workstation, and recording of the electrochemical impedance spectrum (EIS) of the symmetrical battery under the following specific test conditions: sinusoidal AC voltage excitation with an amplitude of 5 mV and a frequency range of 0.1 Hz–106 Hz; in combination with an equivalent circuit and an impedance decomposition model, an in-depth analysis of the impedance composition is performed to obtain a Nyquist diagram and a Bode diagram; then, Z-view or EC-Lab software is used for fitting, and then, by adjusting the value of each impedance, the degree of overlap between the simulated and measured diagrams is increased to obtain the ion transport impedance of the ions in the terminal.

[0078] In the specific embodiments of the present invention, the weight fraction of carbon material and silicon oxide is detected as follows: After decomposition of the secondary battery under a nitrogen atmosphere and separation and removal of the negative terminal, the active material layer of the negative electrode is peeled off the negative electrode current collector; the active material layer of the negative electrode is dissolved in N-methyl-2-pyrrolidone to collect the active material of the negative electrode; then the weight of the carbon material contained in the active material of the negative electrode is measured using a combustion method and recorded as m1; the proportion of silicon is determined by optical ICP emission spectroscopy and ICP mass spectrometry; and the combination state of silicon and (i.e., the value of x in SiO) is determined by X-ray photoelectron spectroscopy (XPS). x) checked to specify the composition and weight of the silicon oxide, and it is recorded as m2; then the weight fraction of the silicon oxide relative to the total amount of carbon material and silicon oxide (m%) = m2 / (m1+m2) × 100%. Example 1

[0079] The present embodiment provides a lithium-ion battery which is manufactured as follows: (1) Production of the negative pole piece: (1.1) Production of the active material of the negative electrode: Mixing a carbon source precursor (petroleum asphalt powder) and a doping element precursor (ammonium persulfate and / or aluminum fluoride) and reacting at 150°C for 7h to obtain the modified carbon source precursor; The resulting modified carbon source precursor is graphitized at A1°C for A2 h under a nitrogen atmosphere, cooled and crushed to obtain a carbon material containing the doping element; Silicon, silicon dioxide, and dopants (aluminum monomers and / or sulfur monomers) are mixed in a 1:1 ratio between silicon and silicon dioxide, and the mixture is subjected to ball milling at B1 rpm for B2 h, heated gasification at B3°C for B4 h under evacuation to a vacuum of 10 Pa, rapid cooling in an environment of 25°C, and coarse and fine comminution in an air-flow mill to obtain the intermediate product (SiO₂). xwith dopants); then the intermediate product is placed in a rotary kiln, and vapor deposition is carried out in a nitrogen environment by introducing acetylene. The vapor deposition temperature is controlled to 800–850°C, forming a carbon layer that covers the surface of the intermediate product. The acetylene introduction rate and the vapor deposition time are controlled so that the weight of the covering carbon layer is approximately 3.5 wt% of the product weight. In this way, a silicon oxide material with dopants is produced, the inner core being composed of SiO₂. x consists of doping elements and the outer layer is covered with a carbon layer; The carbon material containing the dopant and the silicon oxide material containing the dopant are mixed in a weight ratio of 95:5 to obtain the active material of the negative electrode.

[0080] The specific settings for A1-A2 and B1-B4 are listed in Table 1;

[0081] The values ​​of W Al and W S are adjusted to meet the values ​​specified in Table 2 by controlling the addition amounts of dopant precursors (ammonium persulfate, aluminium fluoride) and dopant elements (aluminium monomers and / or sulfur monomers); (1.2) Mixing the active material of the negative electrode, the conductive agent (CNT), the thickening agent (carboxymethylcellulose, CMC) and the binder (styrene-butadiene rubber, SBR) in a mass ratio of 96:2:1:1 and preparing a negative electrode slurry by the wet process using a vacuum mixer, uniformly applying the negative electrode slurry to both sides of the negative electrode current collector (copper foil) and transferring the negative electrode current collector coated with the negative electrode slurry to an oven for drying, then obtaining the negative pole piece by rolling and cutting; the values ​​of the ion transport impedance R and the contact angle α are adjusted by controlling the specific parameters of A1-A2 and B1-B4 as well as the coating and rolling conditions to meet the values ​​specified in Table 2. (2) Production of the positive pole piece

[0082] The active substance of the positive electrode Li(Ni) 0,7 Mn 0,2 Co 0,1 )O2, the binder (polyvinylidene fluoride) and the conductive agent (carbon black) are mixed in a mass ratio of 95:2.5:2.5, and N-methylpyrrolidone (NMP) is added and stirred under the action of a vacuum mixer until the mixing system forms a uniformly moving positive electrode slurry; uniform application of the positive electrode slurry to both sides of the positive electrode current collector (aluminum foil) and transfer of the positive electrode current collector coated with the positive electrode slurry to an oven for drying, then the positive pole piece is obtained by rolling and cutting. (3) Preparation of the electrolyte solution

[0083] Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a weight ratio of 1:1 to obtain an organic solvent, and the lithium salt LiPF6, which is completely dried, is dissolved in the mixed organic solvent, and the mixture is then prepared to form an electrolyte solution with a concentration of 1 mol / L. (4) Production of the diaphragm

[0084] A polyethylene (PE) diaphragm coated with ceramic and polyvinylidene fluoride is used. (5) Battery production

[0085] The positive electrode, diaphragm, and negative electrode, manufactured above, are wound to obtain a bare electrode core without liquid injection; the bare electrode core is placed in a wrapped foil, and the electrolyte solution prepared above is injected into the dried bare electrode core, and the lithium-ion battery is obtained after vacuum encapsulation, standing, chemicalization, shaping, sorting, and other steps. Examples 2-13 and comparative examples 1-3

[0086] Exemplary embodiments 2-13 and comparative examples 1-3 each provide a lithium-ion battery whose manufacturing process is similar to that in exemplary embodiment 1, and the difference is as follows: In embodiments 2-13 and comparative examples 1-3, the values ​​of W are Al and W SThe values ​​of the ion transport impedance R and the contact angle α are adjusted by controlling the addition amounts of dopant precursors (ammonium persulfate, aluminum fluoride) and dopant elements (aluminum monomers and / or sulfur monomers) so that they meet the values ​​specified in Table 2; the values ​​of the ion transport impedance R and the contact angle α are adjusted by controlling the specific parameters of A1-A2 and B1-B4 as well as the coating and rolling conditions to meet the values ​​specified in Table 2; the specific settings of A1-A2 and B1-B4 are listed in Table 1. Examples 14-15

[0087] Exemplary embodiments 14-15 each provide a lithium-ion battery whose manufacturing process is similar to that in exemplary embodiment 1, and the difference is as follows: In embodiment 14, the negative pole piece is manufactured The petroleum asphalt powder undergoes a low-temperature pre-carbonization treatment at 700°C for 5 hours under a nitrogen atmosphere, followed by a high-temperature carbonization treatment at 1590°C for 3 hours. It is then cooled and crushed to obtain a carbon material. The silicon oxide, containing 12 ppm of aluminum and 31 ppm of sulfur, is obtained by sieving. It then undergoes coarse and fine grinding in an air-flow mill to obtain the intermediate product (silicon oxide with dopants). The intermediate product is then placed in a rotary kiln, and vapor deposition is carried out in a nitrogen environment by introducing acetylene. The vapor deposition temperature is controlled to 800–850°C, forming a carbon layer that covers the surface of the intermediate product. The acetylene introduction rate and the vapor deposition time are controlled so that the weight of the covering carbon layer is approximately 3.5 wt% of the product weight. In this way, a silicon oxide material with dopants is produced, the inner core being composed of SiO₂. xconsists of doping elements and the outer layer is covered with a carbon layer; The carbon material and the silicon oxide material containing the doping element are mixed in a weight ratio of 95:5 to obtain the active material of the negative electrode.

[0088] The coating and rolling conditions determine the value of the wetting angle α to meet the values ​​specified in Table 2.

[0089] In embodiment 15, the negative pole piece is manufactured using... The petroleum asphalt powder undergoes a low-temperature pre-carbonization treatment at 730°C for 4 hours under a nitrogen atmosphere, followed by a high-temperature carbonization treatment at 1150°C for 4 hours. It is then cooled and crushed to obtain a carbon material. The silicon oxide, containing 240 ppm aluminum and 260 ppm sulfur, is obtained by sieving. It then undergoes coarse and fine grinding in an air-flow mill to obtain the intermediate product (silicon oxide with dopants). The intermediate product is then placed in a rotary kiln, and vapor deposition is carried out in a nitrogen environment by introducing acetylene. The vapor deposition temperature is controlled to 800–850°C, forming a carbon layer that covers the surface of the intermediate product. The acetylene introduction rate and the vapor deposition time are controlled so that the weight of the covering carbon layer is approximately 3.5 wt% of the product weight. In this way, a silicon oxide material with dopants is produced, the inner core being composed of SiO₂. xconsists of doping elements and the outer layer is covered with a carbon layer; The carbon material and the silicon oxide material containing the doping element are mixed in a weight ratio of 95:5 to obtain the active material of the negative electrode.

[0090] The coating and rolling conditions determine the value of the wetting angle α to meet the values ​​specified in Table 2. Examples 16-17

[0091] Exemplary embodiments 16-17 each provide a lithium-ion battery whose manufacturing process is similar to that in exemplary embodiment 1, and the difference is as follows: In the steps for manufacturing the negative pole piece in embodiments 16-17, the values ​​of W are Al and W SThe values ​​of the ion transport impedance R and the contact angle α are adjusted by controlling the addition amounts of dopant precursors (ammonium persulfate, aluminum fluoride) and dopant elements (aluminum monomers and / or sulfur monomers) so that they meet the values ​​specified in Table 2; the values ​​of the ion transport impedance R and the contact angle α are adjusted by controlling the specific parameters of A1-A2 and B1-B4 as well as the coating and rolling conditions to meet the values ​​specified in Table 2; the specific settings of A1-A2 and B1-B4 are listed in Table 1.

[0092] Furthermore, in the steps for manufacturing the negative pole piece in embodiment 16, the carbon material and the silicon oxide material containing the doping element are mixed in a weight ratio of 99:1 to obtain the active material of the negative electrode.

[0093] In the steps for manufacturing the negative pole piece in embodiment 17, the carbon material and the silicon oxide material containing the doping element are mixed in a weight ratio of 90:10 to obtain the active material of the negative electrode. Table 1 A1 (°C) A2 (h) B1 (rpm) B2 (h) B3 (°C) B4 (h) Example 1 2900 7,5 550 3 1000 5 Example 2 2855 8 550 2,5 1050 5,5 Example 3 2800 8 650 3,5 1100 3 Example 4 3000 7 750 5 900 4,5 Example 5 2600 5 650 4,5 900 6 Example 6 2750 5 700 5 850 4 Example 7 2880 3 650 4 1000 5,5 Example 8 2350 3,5 700 8,5 1050 2 Example 9 2650 4,5 500 3 1200 1,5 Example 10 2500 3 750 3,5 700 5,5 Example 11 2700 4 450 7 750 6 Example 12 3000 6,5 600 3,5 1200 3,5 Example 13 2900 4,5 800 2,5 1150 5 Example 16 2850 4,5 650 10 950 5,5 Example 17 2950 4 750 5,5 900 4 Comparative example 1 2230 7,5 700 3 800 1,5 Comparative example 2 2980 5 600 2 1200 2,5 Comparative example 3 2310 6,5 750 5 750 3,5 Table 2 W Al (ppm) W S (ppm) α(°) R(Ω) lg(W Al ×W S / a) lg(W S ×R)+0,15×R Example 1 10,6 17,8 22,6 1,52 0,922 1,30 Example 2 8 21,5 28,9 1,86 0,775 1,34 Example 3 5,6 16,6 25,4 1,17 0,563 1,33 Example 4 5,0 18,5 35,2 0,22 0,420 1,96 Example 5 4,1 18,5 22,5 1,48 0,528 1,32 Example 6 10,5 3,8 22,9 0,06 0,241 1,81 Example 7 9,7 18,9 25,8 2,59 0,852 1,25 Example 8 5,6 13,7 41,6 0,15 0,266 1,98 Example 9 5,1 4,5 22,1 1,80 0,016 0,67 Example 10 8,9 5,9 32,9 0,85 0,203 0,97 Example 11 10,1 21 22,3 0,61 0,978 1,63 Example 12 1,6 8,6 46,5 0,49 -0,529 1,32 Example 13 11,3 19,8 20,2 0,08 1,044 2,41 Example 14 0,5 1,5 40,1 1,65 -1,728 0,21 Example 15 11,9 12,8 38,0 2,82 0,603 1,08 Example 16 7,5 18,2 28,9 0,28 0,674 1,85 Example 17 6,1 15,9 33,4 1,39 0,463 1,27 Comparative example 1 11,8 21,4 20,3 1,59 1,095 1,37 Comparative example 2 0,7 1,1 48,9 2,21 -1,803 0,03 Comparative example 3 2,9 1,5 43,2 2,93 -0,997 0,15

[0094] The lithium-ion batteries produced according to the exemplary embodiments and comparative examples are tested for their performance as follows: (1) Capacity conservation rate at low temperatures: the lithium-ion battery is discharged at 25°C with a constant current of 1 / 3C to 2.5 V and the capacity is recorded as A0; the same battery is discharged at -10°C with a constant current of 1 / 3C to 2.0 V and the capacity is recorded as A1; the capacity conservation rate (A%) is calculated using the following method: A% = A1 / A0 × 100%; (2) Cycle life: A battery charge / discharge tester is used to charge / discharge the lithium-ion battery at 25°C for the cycle test. Charge / discharge system: The battery is charged to 4.25 V with a constant current of 3C, and then charged at a constant voltage until the current drops to 0.02 C. After standing for 5 minutes, the battery is discharged to 2.5 V with a constant current of 1C, which is 1 cycle. With each cycle, the battery's capacity continuously decreases. When the capacity drops to 80% of the capacity at the first discharge, the number of cycles experienced is recorded as the fast charge cycle life of the battery. (3) Microcrack condition: the lithium-ion battery is disassembled after 200 cycles at 45°C without current, the negative terminal is taken and soaked in DMC for 12 h, then cleaned and dried, and the central area of ​​the negative terminal is cut out as a sample with a length and width of 5×5cm, and the microcracking of the sample is observed in a scanning electron microscope at 500x magnification, the evaluation criteria being as follows: the sample is divided into 25 equal areas in units of 1×1cm, and it is observed whether there are microcracks in each area. Fig. shows part of the SEM image in comparison example 1, and the microcracks are shown as a red circle in Fig.1 shown; if there are 0-2 areas in the sample with microcracks, the microcrack state is class 1; if there are 3-5 areas in the sample with microcracks, the microcrack state is class 2; if there are 6-15 areas in the sample with microcracks, the microcrack state is class 3; if there are 16 or more areas in the sample with microcracks, the microcrack state is class 4.

[0095] The test results are shown in Table 3. Table 3 Capacity retention rate at low temperature Cycle lifespan microcracking condition Example 1 87,8% 3250 Class 1 Example 2 88,3% 3300 Class 1 Example 3 88,1% 3280 Class 1 Example 4 87,2% 3200 Class 1 Example 5 85,2% 3100 Class 1 Example 6 85,8% 3050 Class 2 Example 7 85,2% 3020 Class 1 Example 8 86,0% 3080 Class 1 Example 9 83,5% 2870 Class 2 Example 10 83,1% 2820 Class 2 Example 11 83,9% 2910 Class 1 Example 12 82,4% 2750 Class 2 Example 13 82,8% 2710 Class 2 Example 14 82,2% 2720 Class 2 Example 15 82,3% 2760 Class 2 Example 16 87,5% 3260 Class 1 Example 17 88,4% 3210 Class 2 Comparative example 1 78,9% 2370 Grade 3 Comparative example 2 73,5% 2130 Grade 4 Comparative example 3 75,1% 2020 Grade 4

[0096] It can be seen from the test results in Table 3 that the lithium-ion batteries produced in each embodiment have a capacity retention rate of ≥ 82% at low temperatures, a cycle life of ≥ 2700 and a microcrack condition of class 1 or 2, which indicates that the microcrack condition generated after high temperature cycles is extremely low.

[0097] From the comparison of embodiments 9-11 with embodiments 1-4, it is evident that the lithium-ion battery has a relatively higher capacity retention rate and cycle life at low temperatures if the negative terminal also satisfies equation (3) and / or equation (4) based on the fulfillment of equation (1) and equation (2), and the microcrack condition is class 1 in each case.

[0098] From a comparison of embodiments 5-8 with embodiments 1-4, it is evident that the cycle performance, capacity retention rate, and crack resistance of the manufactured battery are relatively better if the negative terminal continues to satisfy equation (3) and equation (4) under the preferred conditions that W Al 5-10.6 ppm, W S 4.5-21.5 ppm, α 22-35° and R 0.2-2 Ω.

[0099] The relationship between W Al , W S, α and R of the negative pole piece produced in the comparison examples do not satisfy equation (1) and / or equation (2), and the lithium-ion battery to which the negative pole piece is applied has a poor capacity retention rate and a poor cycle life, with a capacity retention rate of less than 79% and a cycle life of 2020-2370 at low temperatures and a large number of microcracks appearing on the surface of the negative pole piece after high-temperature cycles.

[0100] Finally, it should be noted that the foregoing embodiments serve only to illustrate the technical solution of the present invention, rather than to limit it. Although the present invention is explained in more detail in connection with the preferred embodiments, the person skilled in the art should understand that they can modify the technical solutions of the present invention or replace the technical features partially or entirely with equivalent ones without departing from the core and scope of the technical solutions of the present invention. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] Journal of The Electrochemical Society, 2012, 159(7): A1034

[0051]

Claims

[1] A negative pole piece comprising a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material, characterized by that the active material of the negative electrode comprises a carbon material and a silicon oxide, and wherein the active material of the negative electrode also contains aluminum and sulfur elements, wherein the negative pole piece satisfies the relationship shown in equation (1) and equation (2) or the following equations (1) and (2): −1.75≤lg(WAl×Ws / α)≤1.05, 0.2≤lg(Ws×R)+0.15×R≤2.5, and where W Al and W S are the mass fraction of the aluminum element and sulfur element in the active material of the negative electrode, both in ppm; and wherein α is the contact angle between the negative electrode active material layer and a solvent in °, and the solvent is a mixed solution of vinyl carbonate and methyl ethyl carbonate in a weight ratio of 1:1; and where R is the ion transport impedance or ion transmission impedance of the negative pole piece in Ω. [2] Negative pole piece according to claim 1, characterized by that the negative pole piece satisfies the relationship equation described in equation (3) or the following equation (3): 0.2≤lg(WAl×Ws / α)≤0.

95. [3] Negative pole piece according to one of the preceding claims, characterized by that the negative pole piece satisfies the relationship equation described in equation (4) or the following equation (4): 1.25≤lg(Ws×R)+0.15×R≤2.0, [4] Negative pole piece according to one of the preceding claims, characterized by that the W Al -value is in the range of 0.5 to 12 ppm. [5] Negative pole piece according to one of the preceding claims, characterized by that the W S -value is in the range of 1.0 to 22 ppm. [6] Negative pole piece according to one of the preceding claims, characterized by that the W Al -value is in the range of 5.0 to 10.6 ppm. [7] Negative pole piece according to one of the preceding claims, characterized by that the W S -value is in the range of 4.5 to 21.5 ppm. [8] Negative pole piece according to one of the preceding claims, characterized by that the α value is in the range of 20 to 50°. [9] Negative pole piece according to one of the preceding claims, characterized by that the α value is in the range of 22 to 35°. [10] Negative pole piece according to one of the preceding claims, characterized by that the R value is in the range of 0.05 to 3 Ω. [11] Negative pole piece according to one of the preceding claims, characterized bythat the R value is in the range of 0.2 to 2 Ω. [12] Negative pole piece according to one of the preceding claims, characterized by that the weight fraction of silicon oxide is in the range of 1 to 10 wt.% based on the total weight of the carbon material and the silicon oxide. [13] A negative pole piece according to any one of the preceding claims, wherein the carbon material comprises graphite. [14] A negative pole piece according to any one of the preceding claims, wherein the carbon material comprises a material having a graphite-like crystal structure, e.g. natural graphite, artificial graphite, intermediate phase carbon microspheres and the like. [15] A negative pole piece according to any one of the preceding claims, wherein the silicon oxide is SiO x includes, where 0 <x<2. [16] Negative pole piece according to one of the preceding claims, wherein copper, stainless steel, aluminum, nickel, titanium, burnt carbon or an aluminum-cadmium alloy is provided or used for the negative pole piece. [17] A negative pole piece according to any one of the preceding claims, wherein the negative electrode active material layer of the negative pole piece comprises, in addition to the negative electrode active material, a conductive agent and a binder. [18] A negative pole piece according to claim 17, wherein the conductive agent comprises carbon powder, graphite powder, conductive fiber, or conductive whiskers. [19] A negative pole piece according to claim 17 or 18, wherein the binder comprises a polymeric material. [20] A negative pole piece according to any one of claims 17 to 19, wherein a thickener, eg carboxymethyl cellulose, is incorporated into the layer of active material of the negative electrode. [21] Secondary battery, in particular a lithium-ion battery, comprising a positive pole piece, a negative pole piece and an electrolyte solution or electrolyte, characterized by that the negative pole piece is a negative pole piece according to one of claims 1 to 20. [22] Secondary battery according to claim 21, the positive pole piece a current collector of the positive electrode, and a layer of positive electrode active material disposed on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode active material. [23] A secondary battery according to claim 22, wherein copper, stainless steel, aluminum, nickel, titanium, burnt carbon or an aluminum-cadmium alloy is provided or used for the current collector of the positive electrode. [24] A secondary battery according to claim 22 or 23, wherein the current collector of the positive electrode is identical to or different from the current collector of the negative electrode. [25] A secondary battery according to any one of claims 22 to 24, wherein the positive electrode active material comprises a lithium composite metal oxide comprising lithium and at least one metal selected from the group consisting of Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb and Bi. [26] A secondary battery according to any one of claims 22 to 25, wherein the positive electrode active material comprises at least one of Li(Ni 0,6 Mn 0,2 Co 0,2 )O2 and Li(Ni 0,7 Mn 0,2 Co 0,10 )O2. [27] A secondary battery according to any one of claims 22 to 26, wherein the positive electrode active material comprises at least one of Li(Ni 0,8 Mn 0,1 Co 0,1 )O2, Li(Ni 0,8 Co 0,15 Al 0,15 )O2 and Li(Ni 0,86 Mn 0,07 Co 0,05 Al 0,02 )O2. [28] A secondary battery according to any one of claims 22 to 27, wherein the positive electrode active material is Li(Ni 0,9 Mn 0,05 Co 0,05 )O2. [29] A secondary battery according to any one of claims 22 to 28, wherein the positive electrode active material layer comprises a conductive agent. [30] A secondary battery according to any one of claims 22 to 29, wherein the positive electrode active material layer comprises a binder. [31] A secondary battery according to any one of claims 22 to 30, wherein the electrolytic solution comprises an electrolyte and a / the solvent. [32] A secondary battery according to any one of claims 22 to 31, wherein the electrolyte comprises a lithium salt. [33] A secondary battery according to claim 32, wherein the lithium salt is an inorganic lithium salt and / or an organic lithium salt. [34] A secondary battery according to any one of claims 22 to 33, wherein the solvent is a non-aqueous solvent. [35] A secondary battery according to any one of claims 22 to 34, wherein the solvent comprises at least one of the following: vinyl carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate or halogenated derivatives thereof. [36] A secondary battery according to any one of claims 21 to 35, comprising a diaphragm between the positive pole piece and the negative pole piece. [37] A secondary battery according to claim 36, wherein the diaphragm comprises at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester and natural fiber. [38] A secondary battery according to any one of the preceding claims for use in supplying power to a power-consuming device, the device comprising: Electric motor, heater or heat engine, light source, electric vehicle, train, ship, satellite, energy storage system, mobile phone, laptop, drone, sweeping robot, or electronic cigarette. [39] The secondary battery of claim 38, wherein the electric vehicle is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, or an electric truck. [40] Power-consuming device, characterized bythat it comprises a secondary battery according to one of claims 21 to 39. [41] A power consuming device according to claim 40, wherein the secondary battery serves as a power supply for the power consuming device. [42] Power-consuming device according to claim 40 or 41, which is designed as an electric motor, heater or heat engine, light source, electric vehicle, train, ship, satellite, energy storage system, mobile phone, laptop, drone, sweeping robot, or electronic cigarette. [43] The power consuming device of claim 42, wherein the electric vehicle is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, or an electric truck.

Images