Graphite-based electrochemical cell

Abstract

The present invention relates to an electrochemical cell comprising a graphite working electrode and a counter electrode and to a method for charging and / or discharging said electrochemical cell. A method of preparing the electrochemical cell and an electrochemical cell obtained or obtainable by the method are also described. In the present invention, the working electrode active material comprises graphite particles having a particle length D50w in terms of volume D50, and the counter electrode active material, such as LCO or NCM, comprises particles having a particle length D50c in terms of volume D50, where D50w and D50c satisfy formula (Ia): D50c = C50 * D50w, where C50 is 6 or less, preferably 4 or less, more preferably 3 or less, and more preferably 2 or less.

Description

[0001] Cross-references to related applications

[0002] This case claims the rights and priorities of GB 2315718.3, filed on 13 October 2023 (13.10.2023), the contents of which are hereby incorporated by reference in their entirety. Technical Field

[0003] This invention relates to an electrochemical cell unit comprising a graphite working electrode and a counter electrode, and a method for charging and / or discharging said electrochemical cell unit. A method for preparing said electrochemical cell unit and an electrochemical cell unit obtained or obtainable by said method are also described. Background Technology

[0004] High-rate lithium-ion battery electrode materials are capable of receiving large amounts of energy in just a few minutes of charging. These batteries are becoming increasingly important in electric vehicles, grid-scale batteries, and power-intensive devices.

[0005] Granular electrodes are typically used as both the working and counter electrodes. While granular electrodes are easy to manufacture and offer good physical properties, particles limit lithium-ion diffusion. This can lead to poor capacity at high rates because lithium ions cannot penetrate the entire electrode layer. These limitations are exacerbated at high charge rates, where lithium-ion diffusion is at its fastest.

[0006] For example, graphite is widely used as an anode working electrode material due to its relative abundance, low cost, and relatively high energy density. However, developments surrounding graphite particles in electrodes typically focus on improving packing efficiency and electrode density in order to increase volumetric capacity and volumetric energy density.

[0007] Despite the good lithium-ion mobility within graphite particles, graphite has traditionally been avoided in high-rate applications due to the risks of particle breakage and lithium dendrite formation during fast charging. This limits the use of graphite anodes in high-rate applications because lithium deposition can occur at the surface if the charging rate exceeds the lithium-ion insertion rate. Such deposition leads to rapid capacity decay and, if lithium dendrites develop, can cause potential safety incidents. Similarly, for cathode electrode materials, the use of granular electrodes limits the fast-charging capability of the battery cell.

[0008] Therefore, there is a need to provide new working electrode and counter electrode materials for electrochemical battery cells, which can operate at high rates and have good capacity retention and good lifetime capacity retention. Summary of the Invention

[0009] In summary, the inventors of this invention provide a graphite-based electrochemical battery cell optimized for fast charging performance.

[0010] The electrochemical battery unit is a graphite-containing electrochemical battery unit. The electrochemical battery unit uses graphite as the electrode active material.

[0011] The inventors have determined that electrochemical cell cells exhibit improved high-rate capacity when the working electrode and counter electrode contain active particles of complementary sizes. In particular, for a working electrode (e.g., the anode) with a specific particle size, using a counter electrode with the same or slightly larger particle size as the working electrode has been shown to provide improved high-rate capacity. Specifically, it has been found that providing working and counter electrodes with particles having similar particle size distributions (e.g., similar D10, D50, and D90 values) results in excellent high-rate performance.

[0012] The inventors have also discovered that working electrode active materials with graphite particles having a specific size distribution (such as a high distribution width of D10, D50, and D90 values) provide excellent electrochemical performance. It has been found that using graphite particles with a bimodal particle size distribution particularly improves the characteristics of the battery cell.

[0013] Not wanting to be bound by theory, they believed that a wider range of particle sizes on the working electrode reduced the tortuosity of lithium ions in the electrolyte. They have determined that this can be quantitatively identified by the tap density of the graphite particles, where the tap density is 0.8 g / cm³. 3 Or smaller, preferably 0.7 g / cm³ 3 or smaller, and more preferably 0.65 g / cm 3 Or even smaller. It can also be quantified by the BET surface area of ​​the graphite particles, such as 4 m². 2 / g or greater, preferably 5 m 2 / g or greater, more preferably 6 m 2 / g or larger BET surface area.

[0014] Relatedly, the inventors have discovered that counter electrode active materials composed of particles with similar particle size distributions (e.g., LCO, NCM, NCA particles) provide excellent complementarity to graphite working electrodes. The low distribution of particles in the counter electrode active material can also improve the cycle characteristics of the battery cell, together with the complementary graphite working electrode.

[0015] Therefore, in general, the present invention provides an electrochemical battery cell comprising a working electrode having working electrode active material particles and a counter electrode having counter electrode active material particles, wherein the particle size ratio between the counter electrode active material and the working electrode active material is 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. In some embodiments, the ratio is 3 or less, preferably 2.5 or less, and more preferably 2 or less.

[0016] In a first aspect of the invention, an electrochemical battery cell is provided, the electrochemical battery cell comprising a working electrode, a counter electrode, and an electrolyte, wherein...

[0017] The working electrode comprises a working electrode active material, and the working electrode active material comprises particles with a particle length D50 by volume. w Graphite particles,

[0018] The counter electrode comprises a counter electrode active material, and the counter electrode active material comprises particles with a particle length D50 by volume. c Graphite particles, of which D50 w and D50 c Satisfying equation (Ia):

[0019] D50 c = C 50 × D50 w (Ia)

[0020] Where C 50 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

[0021] Preferably, C 50 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0022] C 50 Typically greater than 0.

[0023] In some embodiments, the particle length distribution width S of the graphite particles w The value is 1.6 or greater, wherein the distribution width is defined by equation (IIa):

[0024] S w = (D90 w - D10 w ) / (D50 w (IIa)

[0025] Where D90w and D10w are the volumetric lengths of the graphite particles, D90 and D10.

[0026] In some embodiments, the electrode active material includes a particle length distribution width S c For particles of 1.6 or smaller, the distribution width is defined by equation (IIb):

[0027] S c = (D90 w - D10 w ) / (D50 w (IIb)

[0028] Where D90w and D10w are the particle lengths of D90 and D10 by volume of the electrode active material particles.

[0029] In a preferred embodiment, the electrode active material comprises graphite particles having a bimodal particle length distribution.

[0030] In some preferred embodiments, the first group of graphite particles has a particle length D50 by volume. w1 The second group of graphite particles has a particle length D50 by volume. w2 D50 w1 and D50 w2 Satisfying equation (IIIa):

[0031] D50 w1 = E 50 × D50 w2 (IIIa)

[0032] Where E 50 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0033] E 50 Typically greater than 0.

[0034] In a second aspect of the invention, a method is provided for charging and / or discharging an electrochemical battery cell of the first aspect of the invention at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

[0035] In some embodiments, the method is a method of charging at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

[0036] In some embodiments, the method includes cycling the electrochemical battery cell to charge and discharge, and

[0037] (i) After 1000 cycles at a C-rate of 1C, the discharge capacity retention is 90% or greater, and / or

[0038] (ii) After 2000 cycles at a charge rate of 6C and a discharge rate of 1C, the specific discharge capacity retention is 80% or greater.

[0039] In another aspect, a battery is provided comprising two or more electrochemical battery cells of the first aspect of the present invention.

[0040] In another aspect, the use of the electrochemical battery cell of the first aspect of the invention is provided for charging and / or discharging at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

[0041] Conventional development of electrochemical battery cells focuses on increasing particle density, as this improves volumetric capacity and volumetric energy density and allows for more efficient particle packing. Using materials with lower tap density is counterintuitive. The inventors have identified key parameters enabling fast charging using a graphite working electrode and complementary counter electrodes.

[0042] An inverse linear relationship has also been found between graphite tap density and rechargeability at very high rates. Tap density is related to powder particle size distribution and morphology, and the difference between tap density and true density represents the void volume, which may facilitate ion transport when the electrolyte is filled in the calendered electrode.

[0043] The particle size used in the working electrode and counter electrode is associated with electrodes that have relatively low tap density and a large number of voids, which increases the diffusion of lithium ions in the electrode as the electrolyte can flow in and through these voids.

[0044] The electrochemical battery cells described herein typically have fast charging capability in the 5C-20C range, excellent cycle life, and can operate in this manner while achieving an energy density of 200 Wh / kg or greater.

[0045] These and other aspects and embodiments of the invention are described in more detail below. Attached Figure Description

[0046] The invention is described with reference to the accompanying drawings listed below.

[0047] Figure 1 The correlation between post-formation DCR (bottom), 20C charge capacity (top), and graphite tap density in 2025 half-coin cells using CMC:SBR binder.

[0048] Figure 2Lithium intercalation voltage characteristic curves of high-energy, high-tap-density graphite sample A (top) and low-tap-density, fast-charging graphite sample F (bottom) at charging rates of 0.5, 1, 2, 5, 10, and 20C.

[0049] Figure 3a: Lithium insertion rate capability of half-coin cell with graphite anodes F, G or F and G in a 1:1 weight ratio at charge rates of 0.2, 0.5, 1, 2, 5 and 10C. The error bars show the standard deviation.

[0050] Figure 3b: Lithium-depletion rate capability of half-coin cell with graphite anodes F, G or F and G in a 1:1 (by weight) blend at discharge rates of 0.1, 0.2, 0.5, 1, 2, 5 and 10C. The error bars show the standard deviation.

[0051] Figure 4 For CMC:SBR or PVDF adhesives, the correlation coefficient between capacity and graphite tap density varies with the charge rate.

[0052] Figure 5 Capacity retention of a half-coin cell using LCO sample A or B as the cathode active material and graphite sample F as the anode active material at 0.1, 0.2, 0.5, 1, 2, 5, 10 and 20C during charging and discharging.

[0053] Figure 6 SEM images of dry graphite powder samples A (right) and F (left) at 2k magnification.

[0054] Figure 7 The figure shows the coating weight, layer thickness, and coating density (calendering density) of graphite anode samples AG and F+G.

[0055] Figure 8 : A graph showing the capacity retention of a pouch cell using NCM811 as the cathode active material and graphite sample F as the anode active material under 12 C charging and 1 C discharging. Detailed Implementation

[0056] In general, the present invention provides an electrochemical battery cell comprising a working electrode having working electrode active material particles and a counter electrode having counter electrode active material particles, wherein the particle size ratio between the counter electrode active material and the working electrode active material is 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. In some embodiments, the ratio is 3 or less, preferably 2.5 or less, and more preferably 2 or less.

[0057] In a first aspect of the invention, an electrochemical battery cell is provided, the electrochemical battery cell comprising a working electrode, a counter electrode, and an electrolyte, wherein...

[0058] The working electrode comprises a working electrode active material, and the working electrode active material comprises particles with a particle length D50 by volume. w Graphite particles,

[0059] The counter electrode comprises a counter electrode active material, and the counter electrode active material comprises particles with a particle length D50 by volume. c Graphite particles, of which D50 w and D50 c Satisfying equation (Ia):

[0060] D50 c = C 50 × D50 w (Ia)

[0061] Where C 50 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

[0062] In some implementation schemes, C 50 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0063] Some granular graphite working electrodes are known.

[0064] CN 113140697 describes a battery cell comprising an LCO coating (with particles having a D50 of 10 to 12 µm) on a cathode and a graphite anode comprising particles with a D50 of 10 µm. However, the described particle size is much larger than that of the present invention. The tap density of the particles is also not described.

[0065] US 2023 / 0016746 relates to multilayer silicon or silicon oxide anodes. These examples describe silicon and graphite composite anodes. A specific example includes a particle size of 16.7 µm and a tap density of 0.91 g / cm³. 3 Graphite particles, and LiNi with particles having a D50 of 15 µm. 0.6 Co 0.2 Mn 0.5 O2 cathode. This produces 0.9 C. 50 The values ​​are beyond the preferred range of this invention. The document also does not describe the particle size or tap density of the graphite used in this invention. The described anode also contains a significant amount of silicon, therefore graphite is not the primary active material.

[0066] CN 107910483 describes an LCO-graphite solar cell, wherein the D50 of the LCO particles is 5 to 10 µm, and the D50 of the graphite particles is 4 to 10 µm. The example uses LCO particles with a D50 of 6 µm and graphite particles with a D50 of 8 µm. The example produces a C0.75. 50 The values ​​are beyond the preferred scope of the invention. Furthermore, preferred particle distributions (e.g., D10 and D90 values), bimodal particle size distributions, and tap density of graphite are not described.

[0067] KR 1020230131294 describes examples of graphite anode materials with D50 ranging from 5 to 16 μm in Table 1. No information is provided regarding cathode particle size.

[0068] US 7749659 relates to lithium-ion batteries with spherical graphite particles as the anode and defines the logarithmic relationship between the D10, D50, and D90 values ​​of the graphite. Preferred embodiments refer to a mixture of large and small graphite particles. These examples use an LCO cathode. However, no information is available regarding the particle size of the cathode material.

[0069] WO 2021 / 125755 describes an anolyte active material that is a multilayered particle comprising a core of graphite and pitch coke and a shell coating of hard carbon. The particle's D50 is claimed to be 14-19 μm, but the D50 mentioned in the example is 6-9 μm. The document does not describe the particle size of the cathode and is therefore irrelevant to this invention.

[0070] CN 110649256 B describes a high-energy-density graphite anode material composed of a mixture of single and secondary particles, and its preparation therein. The particles are designed to increase the tap density of the electrode and thus increase the energy density of the battery cell. CN111725485 B and CN 112397691 A also describe increasing the energy density of graphite electrodes by increasing the compressive density of graphite particles.

[0071] Conversely, the inventors of this invention have discovered that providing graphite particles with low tap density is surprisingly beneficial to the fast charging and discharging characteristics of the electrode. Low tap density can be achieved by providing graphite particles with a particle length distribution width A of 1.6 or greater. The relatively large distribution width reduces the electrode's packing efficiency, thus reducing the tap density. Furthermore, matching graphite particles with complementary cathode particles provides excellent fast charging performance.

[0072] The theoretical density of graphite is 2.26 g / cm³. 3 And therefore 0.8 g / cm 3 A smaller tap density represents a packing efficiency of less than 0.35. 1.5 g / cm³3 Or a lower calendering density represents a packing efficiency of less than 0.66.

[0073] C-rate is a measure of a battery's discharge rate relative to its maximum capacity. C-rate can be defined as the reciprocal of the number of hours required to reach a defined theoretical capacity; for example, 10C corresponds to 6 minutes of discharge or charge time. In this work, C-rate is defined relative to one electron transfer per C6 unit; for example, for graphite, 1C = 372 mA·h·g. -1 20C = 7,440 mA·h·g -1 The theoretical capacity is calculated as follows:

[0074]

[0075] Where n is the number of electrons transferred per unit (in graphite, 1 electron / C6 unit), F is the Faraday constant, and 3.6 is the coulomb ratio with conventional mA·h·g. -1 The conversion factor between them is m, where m is mass / formula unit (72 / C6 unit). Therefore, 1C rate corresponds to a reaction (i.e., insertion or removal) of 1 lithium ion / C6 formula unit per hour.

[0076] High-rate applications can also be described by referring to (weight) current density, for example, when the current density is at least 800 mA·g. -1 or 2000 mA·g -1 Under these circumstances, the relationship between current density and C-rate is as follows:

[0077]

[0078] Therefore, for graphite, 800 mA·g -1 The theoretical current density corresponds to a C-rate of 2.15C, and 2000 mAg -1 The current density corresponds to a C-rate of 5.38C.

[0079] All (weight) capacities are given based on the mass of the active electrode material.

[0080] Electrochemical cell unit

[0081] In a first aspect, an electrochemical battery cell is provided, the electrochemical battery cell comprising a working electrode, a counter electrode, and an electrolyte, wherein...

[0082] The working electrode comprises a working electrode active material, and the working electrode active material comprises particles with a particle length D50 by volume. w Graphite particles,

[0083] The counter electrode comprises a counter electrode active material, and the counter electrode active material comprises particles with a particle length D50 by volume. c Graphite particles, of which D50 w and D50 c Satisfying equation (Ia):

[0084] D50 c = C 50 × D50 w (Ia)

[0085] Where C 50 It is 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less. In some embodiments, C 50 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0086] The inventors have discovered that, in order to provide the electrode with a particle length (D50) c The particle length is only slightly larger than or similar to that of the graphite anode (D50). w ) granular electrode materials (e.g., C 50 (3 or less, more preferably 1.0 to 2.0) leads to improved high-rate cycling and long-term battery cell cycling performance.

[0087] In some implementation schemes, C 50 It is 1 to 6, preferably 1.2 to 4, and more preferably 1.4 to 3. In some embodiments, C 50 It is 1 to 3, preferably 1.2 to 2, more preferably 1.4 to 1.6. Preferably, C 50 It is approximately 1.6 C. 50 Typically greater than 0.

[0088] In some implementation schemes, C 50 It is 1 or greater, preferably 1.2 or greater, more preferably 1.4 or greater. In some embodiments, C 50 It is 3 or smaller, preferably 2 or smaller, more preferably 1.6 or smaller.

[0089] In some embodiments, the working electrode active material comprises particles with a particle length D10 by volume D10. w The graphite particles, and the active material for the counter electrode comprises particles with a particle length D10 by volume D10. c Particles, of which D10 w and D10 c Satisfaction Equation (Ib):

[0090] D10 c = C 10 × D10w (Ib)

[0091] Where C 10 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

[0092] In some implementation schemes, C 10 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0093] C 10 Typically greater than 0.

[0094] In some implementation schemes, C 10 It is 1 to 3, preferably 1.2 to 2, more preferably 1.5 to 1.7. Preferably, C 10 It is approximately 1.7.

[0095] In some implementation schemes, C 10 It is 1 or greater, preferably 1.2 or greater, more preferably 1.5 or greater. In some embodiments, C 10 It is 3 or less, preferably 2 or less, more preferably 1.7 or less. Preferably, C 10 It is approximately 1.7.

[0096] In some embodiments, the working electrode active material comprises particles with a volumetric particle length of D90. w The graphite particles, for example, contain electrode active materials with a particle length D90 on a volume basis. c The particles, and of which D90 w and D90 c Satisfaction Equation (Ic):

[0097] D90 c = C 90 × D90 w (Ic)

[0098] Where C 90 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

[0099] In some implementation schemes, C 90 It is 3 or less, preferably 2 or less, more preferably 1.5 or less.

[0100] C 90 Typically greater than 0.

[0101] In some implementation schemes, C 90 It is 1 to 3, preferably 1.1 to 2, more preferably 1.2 to 1.4. Preferably, C 90 It is approximately 1.3.

[0102] In some implementation schemes, C 90 It is 1 or greater, preferably 1.1 or greater, more preferably 1.2 or greater. In some embodiments, C 90 It is 3 or less, preferably 2 or less, more preferably 1.4 or less. Preferably, C 90 It is approximately 1.3.

[0103] In some implementation schemes, C 10 C 50 and C 90 Each is independently 1 or greater, preferably 1.2 or greater. In some embodiments, C 10 C 50 and C 90 Each is independently 2 or smaller, preferably 1.7 or smaller.

[0104] Preferably, C 10 C 50 and C 90 Each is independently 1 to 2, preferably 1.2 to 1.7.

[0105] In some embodiments, the active material of the working electrode comprises a calendering density CD w The graphite particles, and the electrode active material contains calendered density CD c Particles, of which CD w and CD c Satisfaction Equation (IV):

[0106] CD c = F × CD w (IV)

[0107] Wherein F is 3 or less, preferably 2.8 or less, more preferably 2.5 or less, and even more preferably 2.3 or less. F is preferably 1 or greater, more preferably 2 or greater, and even more preferably 2.2 or greater. F can be 1 to 3, preferably 1.5 to 2.8, more preferably 1.8 to 2.5, and even more preferably 2 to 2.5.

[0108] F is typically greater than 0.

[0109] In some embodiments, the working electrode active material comprises materials with a porosity P w Graphite particles, and the electrode active material contains P with porosity. c Particles, of which P w and P c Satisfaction Equation (V):

[0110] P c = G × P w (V)

[0111] Wherein G is 0.5 to 1.5, preferably 0.7 to 1.3, more preferably 0.8 to 1.2, and even more preferably about 1.0. As described herein, porosity may refer to the porosity of the rolled electrode.

[0112] The preferred electrochemical battery cell is a rechargeable electrochemical battery cell, such as a lithium-ion battery cell. A rechargeable battery cell is a type of battery cell that can be recharged.

[0113] During the discharge step, the working electrode can be either an anode or a cathode, as in a lithium-ion battery cell. Preferably, during the discharge step, the working electrode is an anode.

[0114] During the discharge step, the counter electrode can be either an anode or a cathode, as in a lithium-ion battery cell. Preferably, during the discharge step, the counter electrode is a cathode.

[0115] At a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater, the electrochemical cell may be rechargeable and / or dischargeable. At 700 mA g -1 Or larger, preferably 800 mA g -1 Or larger, more preferably 900 mA g -1 Or larger, or even more preferably 1000 mA g -1 At or greater current densities, electrochemical cell units can be rechargeable and / or dischargeable.

[0116] Preferably, after 1000 cycles at a C-rate of 1C, the specific discharge capacity retention is 90% or greater. Preferably, after 2000 cycles at a charge rate of 6C and a discharge rate of 1C, the specific discharge capacity retention is 80% or greater.

[0117] In some implementations, the specific discharge capacity at a C-rate of 5C is 140 mAh / g or greater.

[0118] In some implementations, the specific discharge capacity at a C-rate of 20C is 55 mAh / g or greater.

[0119] working electrode

[0120] The working electrode comprises a working electrode active material, and the working electrode active material comprises particles with a particle length D50 by volume. w Graphite particles.

[0121] Active materials refer to materials that participate in the electrochemical reactions within a battery cell (e.g., materials that carry charge carriers).

[0122] During the discharge step, the working electrode can be either an anode or a cathode, as in a lithium-ion battery cell. Preferably, during the discharge step, the working electrode is an anode.

[0123] In some implementations, the particle length distribution width S of the graphite particles w The value is 1.6 or greater, wherein the distribution width is defined by equation (IIa):

[0124] S w = (D90 w - D10 w ) / (D50 w (IIa)

[0125] Where D90w and D10w are the volumetric lengths of the graphite particles, D90 and D10.

[0126] In some implementation schemes, S w It is 1.65 or greater, preferably 1.7 or greater, more preferably 1.75 or greater. In some embodiments, S w It is 1.6 to 2.0, preferably 1.7 to 1.9, and more preferably 1.75 to 1.85. Preferably, S w It is approximately 1.79.

[0127] D90 can be measured using any suitable method known to those skilled in the art. w D50 w and D10 w Preferably, D90 w D50 w and D10 w Laser diffraction is used for measurement, as described in ISO 13320:2020.

[0128] D50 w D50 is the 50th percentile of graphite particle length by volume. w D90 is the 50th percentile of the particle length of the electrode active material by volume. D10 is the 90th percentile by volume.

[0129] In some implementations, the graphite particles have

[0130] (i) D50 w It is 1 to 20 µm, preferably 2 to 10 µm, more preferably 3 to 7 µm, and even more preferably 3.5 to 4 µm;

[0131] (ii) D10 wIt is 5 µm or smaller, preferably 4 µm or smaller, more preferably 3 µm or smaller, and even more preferably 2 µm or smaller; and / or

[0132] (iii) D90 w It is 30 µm or smaller, preferably 20 µm or smaller, more preferably 15 µm or smaller, and even more preferably 9 µm or smaller.

[0133] In some implementations, the graphite particles have:

[0134] (i) D50 w It is 1 to 8 µm, preferably 2 to 6 µm, more preferably 3 to 5 µm, and even more preferably 3.5 to 4 µm;

[0135] (ii) D10 w It is 5 µm or smaller, preferably 4 µm or smaller, more preferably 3 µm or smaller, and even more preferably 2 µm or smaller; and / or

[0136] (iii) D90 w It is 14 µm or smaller, preferably 12 µm or smaller, more preferably 10 µm or smaller, and even more preferably 9 µm or smaller.

[0137] In some implementations, the D50 of the graphite particles w The particle length is 1 to 8 µm, preferably 2 to 6 µm, more preferably 3 to 5 µm, and even more preferably 3.5 to 4 µm.

[0138] In some implementations, the D10 of the graphite particles w The particle length is 5 µm or less, preferably 4 µm or less, more preferably 3 µm or less, and even more preferably 2 µm or less. The D10 of the graphite particles... w The particle length can be 0.5 to 5 µm, preferably 1 to 4 µm, more preferably 1.2 to 3 µm, and even more preferably 1.5 to 2 µm.

[0139] In some implementations, the D90 of the graphite particles w The particle length is 14 µm or less, preferably 12 µm or less, more preferably 10 µm or less, and even more preferably 9 µm or less. The D90 of the graphite particles... w The particle length can be 6 to 20 µm, preferably 7 to 15 µm, and more preferably 8 to 10 µm.

[0140] In some embodiments, the electrode active material comprises graphite particles having a bimodal particle length distribution.

[0141] A bimodal distribution refers to a particle length distribution having at least two maximum values ​​(e.g., peak values), such as exactly two maximum values. Each maximum value represents the mode particle length. Each maximum value is different, and preferably has a difference of 1 to 10 µm, more preferably 2 to 6 µm, and even more preferably 3 to 4 µm.

[0142] In some embodiments, the first mode length of the graphite particles is 2 µm or greater, more preferably 3 µm or greater, and even more preferably 3.5 µm or greater, and the second mode length is 6 µm or greater, more preferably 7 µm or greater, and even more preferably 7.5 µm or greater. In some such embodiments, the first mode length of the graphite particles is 6 µm or less, more preferably 5 µm or less, and even more preferably 4 µm or less, and the second mode length is 10 µm or less, more preferably 9 µm or less, and even more preferably 8 µm or less.

[0143] In some embodiments, the first mode length of the graphite particles is 2 to 6 µm, more preferably 3 to 5 µm, and even more preferably 3.5 to 4 µm, and the second mode length is 6 to 10 µm, more preferably 7 to 9 µm, and even more preferably 7.5 to 8 µm. In a preferred embodiment, the first mode length of the graphite particles is about 4 µm, and the second mode length is about 7.5 µm.

[0144] It is believed that the bimodal particle size distribution enables a large number of voids in the structure, which allows for increased lithium-ion diffusion and good electrolyte-electrode interaction, while still providing a reasonable level of energy density.

[0145] In some embodiments, the first group of graphite particles has a first mode particle length of 2 to 6 µm, more preferably 3 to 5 µm, and even more preferably 3.5 to 4 µm, and the second group of graphite particles has a second mode particle length of 6 to 10 µm, more preferably 7 to 9 µm, and even more preferably 7.5 to 8 µm.

[0146] In some embodiments, the first group of graphite particles has a particle length D50 by volume. w1 The second group of graphite particles has a particle length D50 by volume. w2 D50 w1 and D50 w2 Satisfying equation (IIIa):

[0147] D50 w1 = E 50 × D50 w2 (IIIa)

[0148] Where E50 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0149] E 50 Typically greater than 0.

[0150] In some implementation schemes, E 50 It is 1 to 3, preferably 1.5 to 2.5, more preferably 1.8 to 2.2. Preferably, E 50 It is approximately 2.0.

[0151] In some embodiments, the first group of graphite particles has a particle length D10 by volume. w1 The second group of graphite particles has a particle length D10 by volume. w2 D10 w1 and D10 w2 Satisfying equation (IIIb):

[0152] D10 w1 = E 10 × D10 w2 (IIIb)

[0153] Where E 10 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0154] E 10 Typically greater than 0.

[0155] In some implementation schemes, E 10 It is 1 to 3, preferably 1.5 to 2.5, more preferably 1.8 to 2.2. Preferably, E10 is about 2.0.

[0156] In some embodiments, the first group of graphite particles has a particle length D90 by volume. w1 The second group of graphite particles has a particle length D90 by volume. w2 D90 w1 and D90 w2 Satisfying equation (IIIc):

[0157] D90 w1 = E 90 × D90 w2 (IIIc)

[0158] Where E 90 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

[0159] E 90 Typically greater than 0.

[0160] In some implementation schemes, E 90 It is 1 to 3, preferably 1.3 to 2.3, more preferably 1.5 to 2.0. Preferably, E90 is about 1.75.

[0161] E 10 E 50 and E 90 Each is independently 1 to 3, preferably 1.5 to 2.5. Preferably, E 10 E 50 and E 90 Each independently ranges from 1.7 to 2.1.

[0162] In some embodiments, based on the total mass of the working electrode, the working electrode contains 90 wt.% or more, preferably 94 wt.% or more, more preferably 96 wt.% or more of electrode active material particles.

[0163] In some implementations, the working electrode is essentially composed of electrode active material particles, such as being composed of electrode active material particles.

[0164] The average aspect ratio of the graphite particles can be 2 or greater, preferably 3 or greater. The aspect ratio is the ratio between the length (the longest dimension of the particle) and the width (the shortest dimension of the particle). As described above for the particle length, both length and width are measured. When viewed from above (e.g., in a 2D planar representation), the width can be considered as the shortest dimension of the particle.

[0165] The sphericity of graphite particles can be 0.9 or less, such as 0.8 or less, such as 0.7 or less. The sphericity of graphite particles can be 0.4 or greater, such as 0.5 or greater, such as 0.6 or greater.

[0166] A relatively high aspect ratio and / or low sphericity further contribute to the low tap density of graphite particles and the associated benefits for high-rate cycling. Secondary particles are preferably non-spherical and typically have an aspect ratio of 2 or greater. This results in undesirable packing characteristics, which are reflected in the low tap density.

[0167] In some implementations, the tap density of the graphite particles is 0.8 g / cm³. 3 Or smaller, preferably 0.7 g / cm³ 3 or smaller, more preferably 0.65 g / cm 3 Or even smaller. The tap density can be 0.5 to 0.8 g / cm³. 3 Preferably, the concentration is 0.55 to 0.7 g / cm³. 3 More preferably 0.60 to 0.65 g / cm³ 3 .

[0168] Tap density can be measured using any suitable method known to those skilled in the art. Preferably, tap density is measured according to ISO 3953:2011.

[0169] In some implementations, the BET surface area of ​​the graphite particles is 4 m². 2 / g or greater, preferably 5 m 2 / g or greater, more preferably 6 m 2 / g or greater. The BET surface area of ​​graphite particles can be 4 to 10 m². 2 / g, preferably 5 to 8 m 2 / g, more preferably 6 to 7m 2 / g.

[0170] The BET surface area can be measured using any suitable method known to those skilled in the art. Preferably, nitrogen adsorption methods such as ISO 9277:2022 are used to measure the BET surface area.

[0171] The working electrode can be adapted to provide 700 mA g -1 Or larger, preferably 800 mA g -1 Or larger, more preferably 900 mAg -1 Or larger, or even more preferably 1000 mA g -1 Or a higher current density.

[0172] The working electrode can be adapted to provide 3.5 mA / cm 2 Or greater, preferably 4 mA / cm 2 or greater, more preferably 5 mA / cm 2 Or a higher current surface density. The working electrode can be adapted to provide 10 mA / cm². 2 Or smaller, preferably 8 mA / cm 2 Or less, more preferably 6 mA / cm 2 Or even lower current surface density. The working electrode can be adapted to provide 3.5 to 10 mA / cm². 2 Preferably 4 to 8 mA / cm 2 Or greater, more preferably 5 to 6 mA / cm 2 The surface current density. This can be determined by the current density (mA g) of the electrode active material. -1 ) × Surface loading (g / cm 2 The surface current density of a lithium-ion battery cell is calculated by multiplying the product of the current and the surface current density. This yields the surface current density (mA / cm²). 2 ).

[0173] The working electrode may include a binder to improve the adhesion of the electrode active material. Typical examples of binders are PVDF, PTFE, CMC, PAA, PMMA, PEO, SBR, and copolymers or mixtures thereof. In some embodiments, the binder is PVDF, CMC, SBR, or a mixture thereof. Preferably, the binder comprises a mixture of CMC and SBR. In some embodiments, the working electrode further includes a binder, wherein the binder is PVDF, CMC, SBR, or a mixture thereof, preferably wherein the binder comprises a mixture of CMC and SBR.

[0174] The binder may be present in any suitable amount, such as 1 to 5 wt.% based on the total mass of the electrodes. Typically, the binder is present in 2.5 wt.% based on the total mass of the electrodes.

[0175] The working electrode is typically fixed to a current collector, such as a copper or aluminum current collector, which can be in the form of a plate. The working electrode can be applied as a layer to the surface of the current collector.

[0176] In some embodiments, the coating density of the electrode active material layer is 1 to 10 mg / cm³. 2 , preferably 3 to 8 mg / cm 2 More preferably 4 to 6 mg / cm 2 .

[0177] In some embodiments, the calendering density of the electrode active material layer is 1.2 to 1.8 g / cm³. 3 Preferably, the concentration is 1.3 to 1.6 g / cm³. 3 The rolling density is determined by measuring the weight and thickness of the electrodes after rolling. The rolling process is described below.

[0178] In some embodiments, the calendered porosity of the electrode active material layer is 20% to 50%, preferably 30% to 40%. This calendered porosity refers to the fraction of the volume containing pores or voids in the calendered electrode. The porosity can be calculated based on a comparison of the material's actual density with its theoretical density.

[0179] In some such embodiments, the graphite particle calendering stacking efficiency of the electrode active material layer is 53% to 62%. In some embodiments, the thickness of the electrode layer is 25 to 50 µm, preferably 30 to 45 µm, more preferably 35 to 40 µm.

[0180] The working electrode may contain conductive additives, such as conductive carbon additives, to improve conductivity. The conductive carbon material may be carbon black, nanoparticle carbon powder, carbon fiber, and / or carbon nanotubes. The conductive carbon material may be Ketjen black or Super P carbon, or hard or soft amorphous carbon. Preferably, the conductive additive is carbon black, carbon nanotubes, or a combination thereof.

[0181] Based on the total mass of the electrodes, the working electrode may contain 1 wt.% or more conductive additives. Preferably, based on the total mass of the electrodes, the conductive additives contain 0.95 wt.% or more carbon black. Preferably, based on the total mass of the electrodes, the conductive additives contain 0.05 wt.% or more carbon nanotubes. In a particularly preferred embodiment, the conductive additives contain about 0.95 wt.% carbon black and 0.05 wt.% carbon nanotubes.

[0182] Based on the total mass of the electrodes, the working electrode may contain 90 wt.% or more, preferably 94 wt.% or more, more preferably 96 wt.% or more of graphite particles.

[0183] In some implementations, graphite is the primary electrode active material in the anode. That is, based on the total mass of the electrode active material in the anode, the electrode active material is 50 wt.% or more graphite.

[0184] In some embodiments, based on the total mass of the electrode, the electrode active material comprises 90 wt.% or more, preferably 94 wt.% or more, more preferably 96 wt.% or more graphite particles.

[0185] In some embodiments, the electrode active material is composed primarily of graphite particles.

[0186] In a particularly preferred embodiment, a working electrode is provided consisting of 96.5 wt.% graphite particles as the electrode active material, 0.95 wt.% C65 and 0.05 wt.% carbon nanotubes as conductive additives, and 2.5 wt.% CMC:SBR (1:1) binder.

[0187] The graphite particles for the working electrode can be prepared using any suitable method known to those skilled in the art. For example, by milling (e.g., bead milling, dry milling, wet milling), grinding, electro-spraying, sintering, calcination, or a combination thereof.

[0188] counter electrode

[0189] The counter electrode comprises a counter electrode active material, and the counter electrode active material comprises particles with a particle length D50 by volume D50. c granules.

[0190] Active materials refer to materials that participate in the electrochemical reactions within a battery cell (e.g., materials that carry charge carriers).

[0191] During the discharge step, the counter electrode can be either an anode or a cathode, as in a lithium-ion battery cell. Preferably, during the discharge step, the counter electrode is a cathode.

[0192] In some embodiments, the electrode active material includes a particle length distribution width S c For particles of 1.6 or smaller, the distribution width is defined by equation (IIb):

[0193] S c = (D90 c - D10 c ) / (D50 c (IIb)

[0194] Among them, D90 c and D10 c The D90 and D10 particle lengths, by volume, are the active material particles for the electrode.

[0195] D90 can be measured using any suitable method known to those skilled in the art. c D50 c and D10 c Preferably, D90 c D50 c and D10 c Laser diffraction is used for measurement, as described in ISO 13320:2020.

[0196] In some implementation schemes, S c It is 1.5 or less, preferably 1.4 or less, more preferably 1.35 or less. In some embodiments, S c It is 1.0 to 1.5, preferably 1.1 to 1.4, more preferably 1.2 to 1.4. Preferably, S c It is approximately 1.33.

[0197] In some embodiments, the particles of the electrode active material have:

[0198] (i) D50 of 2 to 50 µm, preferably 3 to 30 µm, more preferably 4 to 20 µm, and even more preferably 5 to 10 µm c ;

[0199] (ii) D10 of 8 µm or less, preferably 6 µm or less, more preferably 5 µm or less, and even more preferably 4 µm or less. c ; and / or

[0200] (iii) D90 of 6 to 80 µm, preferably 8 to 60 µm, more preferably 9 to 40 µm, and even more preferably 10 to 15 µmc .

[0201] In some embodiments, the particles of the electrode active material have:

[0202] (i) D50 of 2 to 15 µm, preferably 3 to 10 µm, more preferably 4 to 8 µm, and even more preferably 5 to 7 µm c ;

[0203] (ii) D10 of 8 µm or less, preferably 6 µm or less, more preferably 5 µm or less, and even more preferably 4 µm or less. c ; and / or

[0204] (iii) D90 of 6 to 20 µm, preferably 8 to 15 µm, more preferably 9 to 13 µm, and even more preferably 10 to 12 µm c .

[0205] In some embodiments, the D10 of the granular counter electrode material c The particle length (which is the 10th percentile of the particle length of the granular electrode material by volume) is 8 µm or less, preferably 6 µm or less, more preferably 5 µm or less, and even more preferably 4 µm or less.

[0206] In some implementations, the D90 of the granular counter electrode material c The particle length (which is the 90th percentile of the particle length of the granular counter electrode material by volume) is 6 to 20 µm, preferably 8 to 15 µm, more preferably 9 to 13 µm, and even more preferably 10 to 12 µm.

[0207] Suitable counter electrode materials include lithium-containing or lithium-intercalated materials, such as lithium metal oxides, wherein the metal is typically a transition metal, such as Co, Fe, Ni, V, or Mn, or combinations thereof. The counter electrode material may be doped with additional metallic or non-metallic components, or it may be undoped. Preferably, the counter electrode material is undoped.

[0208] Examples of counter electrode materials include lithium cobalt oxide (LiCoO2; LCO), lithium nickel manganese cobalt oxide (NMC, NCM111, NCM532, NCM622, and NCM811), lithium vanadium fluorophosphate (LiVPO4F), lithium nickel cobalt aluminum oxide (NCA, LiNiCoAlO2), lithium iron phosphate (LFP, LiFePO4), and manganese-based spinel (e.g., LiMn2O4). Preferably, the counter electrode material is LCO, NMC, NCA, or a combination thereof. More preferably, the counter electrode material is LCO, NCM, or a combination thereof. NCM is preferably NCM811.

[0209] Conductive carbon materials (e.g., carbon black, graphite, nanoparticle carbon powder, or carbon nanotubes) can be mixed with the counter electrode material. In one embodiment, the counter electrode comprises porous carbon, such as porous reduced graphene oxide.

[0210] In one embodiment, the counter electrode is substantially free of binder.

[0211] In an alternative embodiment, the counter electrode is mixed with an adhesive or binder. Some examples of adhesives or binders include PVDF, PTFE, CMC, PAA, PMMA, PEO, SBR, and their copolymers.

[0212] Typically, the counter electrode is fixed to the current collector substrate, such as an aluminum plate.

[0213] In a preferred embodiment, the granular counter electrode active material is lithium cobalt oxide (LCO).

[0214] In a preferred embodiment, the counter electrode further comprises an adhesive, wherein the adhesive is PVDF, CMC, SBR, or a mixture thereof, preferably wherein the adhesive comprises a mixture of CMC and SBR.

[0215] In a preferred embodiment, based on the total mass of the working electrode, the counter electrode contains 90 wt.% or more, preferably 94 wt.% or more, more preferably 96 wt.% or more of electrode active material particles.

[0216] In a preferred embodiment, the counter electrode is substantially composed of electrode active material particles, such as electrode active material particles.

[0217] In some embodiments, the calendered porosity of the electrode active material layer is 20% to 50%, preferably 30% to 40%. This calendered porosity refers to the fraction of the volume containing pores or voids in the calendered electrode. The porosity can be calculated based on a comparison of the material's actual density with its theoretical density.

[0218] In some embodiments, the calendering density of the electrode active material layer is 2 to 4 g / cm³. 3 The preferred concentration is 3.2 to 3.8 g / cm³. 3 In some implementations, the electrode active material layer is approximately 3.6 g / cm³. 3 The rolling density is determined by measuring the weight and thickness of the electrode after rolling. The rolling process is described below.

[0219] The counter electrode can be adapted to provide 700 mA g -1 Or larger, preferably 800 mA g -1 Or larger, more preferably 900 mA g -1Or larger, or even more preferably 1000 mA g -1 Or a higher current density.

[0220] The counter electrode can be adapted to provide 3.5 mA / cm 2 Or greater, preferably 4 mA / cm 2 or greater, more preferably 5 mA / cm 2 Or a higher surface current density. The counter electrode can be adapted to provide 10 mA / cm². 2 Or smaller, preferably 8 mA / cm 2 Or smaller, more preferably 6mA / cm 2 Or even lower current surface density. The counter electrode can be adapted to provide 3.5 to 10 mA / cm². 2 Preferably 4 to 8 mA / cm 2 Or greater, more preferably 5 to 6 mA / cm 2 The surface current density. As described above for the working electrode, calculate the surface current density.

[0221] Electrode active material particles can be prepared using any suitable method known to those skilled in the art. For example, particles can be prepared by milling (e.g., bead milling, dry milling, wet milling), grinding, electro-spraying, sintering, calcining, or combinations thereof.

[0222] electrolytes

[0223] An electrochemical battery cell also includes an electrolyte. The electrolyte is used to facilitate the flow of ions between the working electrode and the counter electrode. Therefore, the electrolyte is present in the space between the electrodes. Typically, the electrolyte in an electrochemical battery cell is suitable for dissolving lithium ions.

[0224] Typically, the electrolyte in a charged and discharged battery cell contains lithium ions. Typically, the electrolyte comprises a lithium salt, such as LiTFSI (lithium bis(trifluoromethanesulfonyl)imide), LiPF6, LiBF4, LiClO4, LiTF (lithium trifluoromethanesulfonate), or lithium bis(oxalate)borate (LiBOB). In some embodiments, the electrolyte comprises 1.15M LiPF6.

[0225] Electrolytes can be liquid electrolytes, such as liquids at ambient temperature (e.g., at 25ºC).

[0226] The electrolyte can be a non-aqueous electrolyte. The electrolyte can contain a polar aprotic solvent. The electrolyte can contain an organic solvent. Solvents used to dissolve lithium ions are well known in the art.

[0227] Suitable solvents include carbonate solvents. Examples include propylene carbonate (PC), ethylene carbonate (EC), butenyl carbonate (BC), vinyl chloride carbonate, fluorocarbonate solvents (e.g., vinyl fluorocarbonate and trifluoromethyl propylene carbonate), and dialkyl carbonate solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), and ethyl propyl carbonate (EPC).

[0228] Suitable solvents also include sulfone solvents. Examples include methyl sulfone, ethyl methyl sulfone, methyl phenyl sulfone, methyl isopropyl sulfone (MiPS), propyl sulfone, butyl sulfone, tetramethylene sulfone (cyclobutane sulfone), phenyl vinyl sulfone, allyl methyl sulfone, methyl vinyl sulfone, divinyl sulfone (vinyl sulfone), diphenyl sulfone (phenyl sulfone), dibenzyl sulfone (benzyl sulfone), vinyl sulfone, butadiene sulfone, 4-methoxyphenyl methyl sulfone, 4-chlorophenyl methyl sulfone, 2-chlorophenyl methyl sulfone, 3,4-dichlorophenyl methyl sulfone, 4-(methylsulfonyl)toluene, 2-(methylsulfonyl)ethanol, 4-bromophenyl methyl sulfone, 2-bromophenyl methyl sulfone, 4-fluorophenyl methyl sulfone, 2-fluorophenyl methyl sulfone, 4-aminophenyl methyl sulfone, sulactones (e.g., 1,3-propane sulactone), and ether-containing sulfone solvents (e.g., 2-methoxyethyl(methyl) sulfone and 2-methoxyethoxyethyl(ethyl) sulfone).

[0229] Suitable solvents also include silicon-containing solvents, such as siloxanes or silanes. Examples include hexamethyldisiloxane (HMDS), 1,3-divinyltetramethyldisiloxane, polysiloxanes, and polysiloxane-polyoxyethylene derivatives. Some examples of silane solvents include methoxytrimethylsilane, ethoxytrimethylsilane, dimethoxydimethylsilane, methyltrimethoxysilane, and 2-(ethoxy)ethoxytrimethylsilane.

[0230] Typically, electrolytes may contain additives to improve performance. Examples include vinylene carbonate (VC), vinyl ethylene carbonate, allyl ethyl carbonate, tert-butylene carbonate, vinyl acetate, divinyl adipate, acrylonitrile, 2-vinylpyridine, maleic anhydride, methyl cinnamate, vinyl carbonate, halogenated vinyl carbonate, α-bromo-γ-butyrolactone, methyl chloroformate, 1,3-propanesulfonyl lactone, vinyl sulfite (ES), propylene sulfite (PS), vinyl vinyl sulfite (VES), fluoroethylene sulfite (FES), 12-crown-4 ether, carbon dioxide (CO2), sulfur dioxide (SO2), and sulfur trioxide (SO3).

[0231] The additive may be present in the electrolyte in any suitable amount. Typically, the additive is present at 0.1 wt.% or more, such as 1 wt.% or more. The additive may be present at 10 wt.% or less, such as 5 wt.% or less, or 3 wt.% or less. In some embodiments, the additive is present at 0.1 to 5 wt.%, preferably 0.5 to 3 wt.%, preferably 1 to 2 wt.%.

[0232] In some implementations, the electrolyte comprises EC, EMC, and VC solvents. The EC, EMC, and VC solvents may be present in a ratio of 30:70:2 v / v / w.

[0233] Electrochemical cell units may also include a separator in the inter-electrode space. The inter-electrode space is the space between the working electrode and the counter electrode. The separator is typically a solid porous membrane positioned between the working electrode and the counter electrode. The solid porous membrane may partially or completely replace the liquid electrolyte. The solid porous membrane may contain polymers (e.g., polyethylene, polypropylene, or copolymers thereof) or inorganic materials such as transition metal oxides (e.g., titanium dioxide, zirconium dioxide, yttrium trioxide, hafnium dioxide, or niobium pentoxide) or group metal oxides such as silicon oxide, which may be in the form of glass fibers.

[0234] Solid nonporous membranes can contain lithium-ion conductors. Examples include LLZO (garnet family), LSPO (LISICON family), LGPS (sulfide-LISICON family), LATP / LAGP (NASICON family), LLTO (perovskite family), and phosphide / sulfide glass ceramics.

[0235] Preferably, the diaphragm comprises a polymer, such as polyethylene, polypropylene, or copolymers thereof, or comprises glass fiber.

[0236] The separator can have sufficient porosity to facilitate the inter-electrode ion flow required for an electrochemical cell. This can be referred to as the surface current density. It can be determined by the current density (mA g) of the electrode active material. -1 × Surface loading (g / cm) 2 The product of these factors is used to calculate the surface current density of a single charged ion (e.g., lithium). This yields the surface current density (mA / cm²). 2 ).

[0237] For example, when the surface loading of graphite particles is 5 mg / cm² 2 Furthermore, with a current density of 700 mA / g, the surface current density is 3.5 mA / cm². 2 .

[0238] The diaphragm is suitable for receiving 3.5 mA / cm. 2 Or greater, preferably 4 mA / cm2 or greater, more preferably 5 mA / cm 2 Or a higher current surface density. The diaphragm can be adapted to receive 10 mA / cm². 2 Or smaller, preferably 8 mA / cm 2 Or less, more preferably 6 mA / cm 2 Or even lower current surface density. The diaphragm can be adapted to receive currents from 3.5 to 10 mA / cm². 2 Preferably 4 to 8 mA / cm 2 Or greater, more preferably 5 to 6 mA / cm 2 Surface current density.

[0239] Battery

[0240] The present invention also provides a battery comprising one or more electrochemical battery cells of the present invention. The battery may be a lithium-ion battery.

[0241] In the presence of multiple electrochemical cell units, these electrochemical cell units can be connected in series or in parallel to provide power.

[0242] The battery of the present invention can be provided in road vehicles such as cars, buses, mopeds, or trucks. Alternatively, the battery of the present invention can be provided in rail vehicles such as trains or trams. The battery of the present invention can also be provided in electric bicycles (e-bikes), drones, electric aircraft, and electric or hybrid boats. Similarly, the battery of the present invention can be provided in power tools such as electric drills or chainsaws; gardening tools such as lawnmowers, hedge trimmers, or lawn mowers; or household appliances such as toothbrushes, vacuum cleaners, or hair dryers. The battery of the present invention can be used in cameras. The battery of the present invention can be used in robots, such as delivery robots or warehouse automation robots.

[0243] The battery of the present invention can be provided in a regenerative braking system.

[0244] The battery of the present invention can be provided in portable electronic devices such as mobile phones, laptops or tablets.

[0245] The battery of the present invention can be provided in a power grid management system.

[0246] Methods for preparing electrochemical battery cells

[0247] In general, the present invention also provides a method for preparing an electrochemical battery cell in the first aspect.

[0248] The method typically includes the steps of providing a working electrode, a counter electrode, an electrolyte, and an optional separator, and assembling them into an electrochemical cell unit.

[0249] An electrochemical battery cell that can be obtained or acquired by the method is also provided.

[0250] Assembly can be carried out in an oxygen-free and / or moisture-free environment. Oxygen-free or moisture-free typically means that the oxygen or water concentration is less than 1 ppm, preferably less than 0.1 ppm.

[0251] A battery cell can be fabricated by arranging the working electrode, counter electrode, and optional separator in a container and adding an electrolyte.

[0252] The container can be a bag.

[0253] This invention provides a method for preparing a working electrode or counter electrode of an electrochemical battery cell, the method comprising:

[0254] A layer of electrode active material composition is deposited on a substrate.

[0255] The method may further include the step of laminating an electrode active material to form a working electrode.

[0256] The step of depositing a layer of electrode active material composition according to the second aspect on a substrate can be referred to as the "deposition step".

[0257] Preferably, the substrate is a current collector. The current collector can be as described above.

[0258] The deposition step can be performed by any suitable additive manufacturing method such as 3D printing, casting, or other methods known in the art.

[0259] Preferably, the deposition step includes:

[0260] Preparation of electrode active material slurry;

[0261] A layer of slurry is poured onto the substrate; and

[0262] The slurry is dried to form an electrode active material layer.

[0263] A slurry can be prepared by adding a carrier liquid (such as water) to the electrode active material. The slurry is preferably flowable to allow for layer formation. The slurry can be approximately 50 wt.% of an electrode active material composition.

[0264] The process of casting a slurry typically involves adding the slurry to a substrate and allowing it to flow across the substrate to form a layer. The slurry may flow under gravity. Alternatively or additionally, the slurry may be spread to form a layer. Spreading can be achieved by mechanical agitation, ultrasonication, or a mechanical spreader (e.g., blades traveling across the layer surface). The casting step typically forms a uniform composition layer across the substrate surface.

[0265] The drying process typically removes the carrier liquid from the slurry, leaving a dried layer of electrode active material. The drying process can utilize elevated temperatures. It can also utilize reduced pressures. A combination of elevated temperatures and reduced pressures can be used. For example, the electrode can be dried under vacuum at 100ºC for 3 hours.

[0266] Drying conditions may depend on the battery cell assembly process, battery cell type, and drying chamber capacity. When baking electrode cores or stacks, the temperature is limited to approximately 85ºC for several days. If the electrodes can be baked individually, a temperature range of 100ºC–125ºC can be used for 8–12 hours. Drying conditions can be adapted to the adhesive used.

[0267] The step of rolling the electrode active material layer to form the working electrode can be called the "rolling step".

[0268] The calendering step can be performed by any suitable calendering process, such as applying pressure to the working electrode layer using rollers. The calendering step typically provides a uniform layer of working electrode material on the substrate.

[0269] The calendering step can apply sufficient pressure to the working electrode layer to provide 1.2-1.4 g / cm³ for the working electrode layer. 3 The density.

[0270] The calendering step can be performed using a pair of rolls. The rolls apply pressure with a set roll gap. The substrate is then fed through the rolls and thus subjected to pressure from them. The size of the roll gap can correspond to the desired thickness of the final material. Typically, high pressure is used to achieve the desired thickness.

[0271] In some implementations, the rolls are heated during the calendering process.

[0272] Charging and / or discharging methods

[0273] The present invention also provides a method for charging and discharging the electrochemical battery cell or battery of the present invention.

[0274] In another aspect, a method is provided for charging and / or discharging an electrochemical battery cell of the first aspect at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

[0275] In some embodiments, the method includes cycling the electrochemical battery cell by charging and discharging. Preferably, after 1000 cycles at a C-rate of 1C, the specific discharge capacity retention is 90% or greater. Preferably, after 2000 cycles at a charge rate of 6C and a discharge rate of 1C, the specific discharge capacity retention is 80% or greater.

[0276] In some embodiments, the method includes 700 mA g -1 Or larger, preferably 800 mA g -1 Or larger, more preferably 900 mA g -1 Or larger, or even more preferably 1000 mA g -1 Or charge and / or discharge the electrochemical cell at a higher current density.

[0277] In some implementations, the specific discharge capacity at a C-rate of 5C is 140 mAh / g or greater.

[0278] In some implementations, the specific discharge capacity at a C-rate of 20C is 55 mAh / g or greater.

[0279] use

[0280] In another aspect of the invention, the electrochemical battery cell of the fifth aspect of the invention is provided for use in charging and / or discharging at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

[0281] Electrochemical cell units can be used in the methods described herein.

[0282] definition

[0283] As determined by the relevant context, the following common definitions are used in this document.

[0284] Dry weight refers to the mass excluding water. Unless otherwise specified, wt.% is provided in dry weight.

[0285] Other preferred options

[0286] This document explicitly discloses each compatible combination of the implementation schemes described above, as if each combination were listed individually and explicitly.

[0287] Various other aspects and embodiments of the invention will be apparent to those skilled in the art from this disclosure.

[0288] As used herein, “and / or” will be regarded as a specific disclosure of each of the two specified features or components, with or without the other. For example, “A and / or B” will be regarded as a specific disclosure of each of (i) A, (ii) B, and (iii) A and B, as if each were set forth separately herein.

[0289] Unless the context otherwise requires, the description and definition of the features set forth above are not limited to any particular aspect or embodiment of the invention and are equally applicable to all aspects and embodiments described.

[0290] Some aspects and embodiments of the invention will now be described by way of example and with reference to the accompanying drawings.

[0291] Example

[0292] The following embodiments are provided to further illustrate the invention and are not intended to limit the scope of the invention.

[0293] Example 1 - Anode Test

[0294] Seven dry graphite powder samples (sample A to sample G) were prepared using graphite particles.

[0295] Physicochemical characterization of graphite particles

[0296] Analyze the physicochemical properties of each graphite particle in samples A through G.

[0297] Samples A and F were characterized by SEM microscopy at 2000× magnification. SEM images of samples A and F are shown below. Figure 6 In the middle sample, the particles in sample F have a higher aspect ratio and lower sphericity than those in sample A. The small, non-spherical shape of the particles is suspected to be the reason for the very low tap density.

[0298] The BET surface area of ​​samples A through G was measured using ISO 9277:2022. The BET surface area measurement results are shown in Table 1.

[0299] According to ISO 13320:2020, the D10, D50, and D90 particle sizes were measured using laser diffraction. The length of the particles was measured and analyzed to obtain the particle size distribution, from which the D10, D50, and D90 values ​​were calculated. The particle size distribution was calculated on a volumetric basis. The results are shown in Table 1.

[0300] The tap density of samples A through F was measured using ISO 3953:2011. The tap density measurement results are also shown in Table 1.

[0301] Table 1. Physicochemical properties of graphite samples

[0302]

[0303] Sample F has the largest BET surface area. Sample F also has the lowest tap density. This is believed to be because the particles in sample F have the worst packing and therefore the largest number of voids between the particles. This results in the low tap density and high specific surface area of ​​the graphite particles.

[0304] Equation (II) was also used to compare the particle sizes of D90, D50, and D10. The value of “S” in Equation (II) is shown in Table 2.

[0305] S = (D90 - D10) / (D50)(II)

[0306] “S” represents the proportion of the particle size distribution (the difference between the D90 and D10 particle sizes) to the D50 particle size. If the particle size distribution is larger than the D50 particle size, then S is higher. However, if the particle size distribution is smaller than the D50 particle size, then S is lower.

[0307] Table 2. Particle size and “S” value of graphite samples

[0308]

[0309] Sample F has the highest S value, at 1.79. This indicates that sample F has the largest particle size distribution compared to the D50 particle size. In other words, based on the average particle size, its particle size distribution is larger than that of the other samples.

[0310] Electrode preparation

[0311] Graphite electrode active material slurries were prepared using 96.5 wt.% dry graphite powder (samples A to G), 1 wt.% C65 / CNT (0.95 / 0.05 w / w), and 2.5 wt.% CMC:SBR (1:1.5) binder, where wt.% is dry weight. These components were dispersed in approximately 50 ml of deionized water to obtain a 50 wt.% solid dispersion in water. The slurries were then mixed.

[0312] The slurry was prepared at 5 mg / cm 2 The coating weight (dry weight) was applied to the copper foil current collector. The electrode was then dried under ambient conditions. The dried electrode was calendered at room temperature to obtain a coating weight of 1.2–1.4 g / cm³. 3 The rolling density was determined to obtain the graphite working electrode.

[0313] Electrochemical characterization

[0314] The working electrode was evaluated using a 2025 stainless steel coin cell configured as a half-cell unit. The graphite working electrode and lithium counter electrode were dried under vacuum at 100ºC for 3 h, then transferred to an argon-filled glove box without exposure to air. The cell was assembled in the glove box with the electrolyte consisting of 1.15 M LiPF6 in EC, EMC, and VC solvent (30:70:2 v / v). After drying under vacuum at 40ºC for 2 h and transferring to the glove box, a glass fiber separator was used.

[0315] Electrochemical performance was tested by measuring the intercalation and deintercalation capacities at rates of 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 C. The electrochemical performance results are summarized in Table 3. A full charge was considered to be 5 mV relative to Li, and a full discharge was considered to be 2.0 V relative to Li.

[0316] For the first charge and discharge cycle, the DC internal resistance (DC-IR) of the battery cell is measured. The DC-IR is measured by setting the battery cell to a certain state of charge and allowing it to rest for approximately 15 minutes. A current pulse of 1 to 10 seconds is then applied through the battery cell. The difference between the open-circuit voltage (OCV) and the load voltage is then divided by the current at the end of the pulse to obtain the DC-IR value.

[0317] First cycle efficiency (FCE) is measured by comparing the first specific discharge capacity with the first specific charge capacity at a C-rate of C / 10. The first specific discharge capacity (FDC) is also provided in Table 3.

[0318] Specific charge capacity was also measured across different C-rate ranges. Lithium stripping was performed between each test charge at a C-rate of C / 2.

[0319] Table 3. Electrochemical properties of graphite samples tested in 2025 half-coin cell cells using CMC:SBR binder

[0320]

[0321] Sample F exhibited the lowest DC-IR value and the highest specific capacity across all C-rates. At higher C-rates, Sample F's specific capacity was proportionally much higher than that of the other samples. For example, at 0.2C, Sample F's specific capacity was only 20% higher on average than the other samples, while at 5C, 10C, and 20C, Sample F's specific capacity was 37%, 38%, and 42% higher than the other samples, respectively.

[0322] Multivariate correlation analysis of the physical and electrochemical properties of graphite samples A through F revealed a strong correlation between the fast charging capability and DC-IR of the battery cells and the tap density of the graphite powder used to prepare the electrodes. Figure 1 The relationship between specific capacitance and tap density at 20C magnification is plotted (top figure) and the relationship between specific capacitance and tap density at first DC-IR (bottom figure).

[0323] This indicates that the tap density is less than 0.8 g / cm³. 3 Graphite particles are best suited for achieving very fast cell cycle rates (e.g., 10C or 20C) because electrodes incorporating these particles have low DC-IR and high specific capacity at high C-rates.

[0324] The charging voltage characteristic curves were also analyzed in the C-rate range using battery cells including samples A and F. The results are shown in... Figure 2 The figure shows the relationship between cell voltage and specific charge capacity for samples A and F. It can also be seen that, at different C-rates, the voltage characteristic curve of sample F is much flatter and more consistent, indicating that the energy barrier for lithium intercalation is less dependent on the degree or rate of lithium intercalation. Comparing the lithium intercalation characteristic curves of high-tap-density graphite and low-tap-density graphite, it is considered that lithium diffusion is easier in low-tap-density electrodes because the electrode potential is less dependent on the lithium concentration in the electrode.

[0325] To avoid being bound by theory, it is believed that low tap density graphite powder provides more voids in the electrolyte to transport lithium through the electrode body, thereby leading to improved lithium diffusion.

[0326] Furthermore, anisotropic particle orientation in the electrode can lead to higher rate capability, while isotropic orientation (e.g., the presence of large, thin flakes parallel to the current collector) will cause ion transport obstruction in the direction perpendicular to the current collector. For the same pore volume (i.e., the same electrode density), larger particles will exhibit greater tortuosity in the direction perpendicular to the current collector plane.

[0327] Particle D 50 Size distribution and aspect ratio are the reasons for low tap density.

[0328] The anisotropy of particle orientation in the electrode is likely the reason for its high-rate cycling performance.

[0329] Other anode particle mixtures

[0330] Other graphite electrode active material slurries were prepared using 96.5 wt.% dry graphite powder, 1 wt.% C65 / CNT (0.95 / 0.05 w / w), and 2.5 wt.% CMC:SBR (1:1.5) binder, where wt.% is dry weight. In this example, the dry graphite powder used was a 1:1 weight mixture of sample F and sample G (as described above). These components were dispersed in approximately 50 ml of deionized water to obtain a 50 wt.% solid dispersion in water. The slurries were then mixed.

[0331] The slurry was prepared at 5 mg / cm 2 The coating weight (dry weight) was applied to the copper foil current collector. The electrode was then dried at 85ºC. The dried electrode was calendered at room temperature to obtain a coating weight of 1.2–1.4 g / cm³. 3 The rolling density was determined to obtain the graphite working electrode.

[0332] The lithium foil counter electrode was prepared as described above.

[0333] As described above, the working electrode was evaluated using a 2025 stainless steel coin cell with a half-cell configuration. Electrochemical performance was tested as described above. The electrochemical performance results are summarized in Table 3 and graphically presented in Figures 3a and 3b.

[0334] Figure 3a shows that the charge rate capacity of the anode formed by the mixture of samples F and G is very similar to that of sample F at rates from 0.2 to 10 C. The charge rate capacity of the anode formed by the mixture of samples F and G is also greater than that of sample G at all tested C-rates.

[0335] Figure 3b shows that the discharge rate capacity of the anode formed by the mixture of samples F and G is slightly higher than that of samples F and G alone when used at discharge rates from 0.1 to 2C. At higher discharge rates of 5C and 10C, the discharge rate capacity of the anode formed by the mixture of samples F and G is similar to that of sample F, but still greater than that of sample G.

[0336] A mixture of samples F and G offers similar or better charge / discharge capacity benefits, while having a lower BET surface area and tap density than sample F overall. Therefore, a bimodal mixture of samples F and G provides similar or better electrochemical properties with greater volumetric capacity and energy density.

[0337] Other anode adhesives

[0338] The alternative graphite electrode was prepared using the method described above for graphite samples A to F, but with 2.5 wt.% PVDF binder instead of CMC:SBR binder. This electrode was then assembled into a 2025-type stainless steel coin cell in a half-cell configuration, as described above.

[0339] The electrochemical performance of the battery cell was tested by measuring the insertion and extraction capacities at rates of 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20C to determine the specific discharge capacity at these different rates. The results are shown in Table 4.

[0340] Table 4. Electrochemical properties of graphite samples tested in 2025 half-coin cells using PVDF binder

[0341]

[0342] A multivariate correlation analysis was performed between tap density and specific discharge capacity, and Figure 4 Results for electrodes using CMC:SBR and PVDF adhesives are shown.

[0343] Figure 4The study shows that the observed correlation increases with charge rate capability; that is, the faster the charge rate required for graphite, the lower the required tap density. This correlation is observed for both PVDF and CMC:SBR binders. Not wanting to be bound by theory, it is assumed that ion transport becomes a limiting factor at high charge rates; therefore, it is understandable that lower powder tap density has a beneficial effect on the ion transport capability of the electrode, and thus the correlation strengthens as the charge rate increases.

[0344] Different adhesives and adhesive systems may have varying degrees of adhesive and cohesive strength, electrolyte swelling, and insulation properties, which can affect the resistance or impedance of the battery cell. Some adhesives and adhesive systems may also affect electrode porosity and the availability of electrolyte in contact with the particle surface. If the cohesive and adhesive strengths are poor, the anode particles may become electrically isolated during cycling, leading to capacity loss and increased impedance.

[0345] Example 2 - Cathode Test

[0346] Two samples (samples LCO-A and LCO-B) of dry LCO powder were prepared using lithium cobalt oxide (LCO) particles. NCM811 particles were also prepared.

[0347] Physicochemical characterization of LCO particles

[0348] The physicochemical properties of the particles in samples LCO-A, LCO-B and NCM811 were analyzed.

[0349] The BET surface area of ​​samples LCO-A, LCO-B, and NCM811 was measured using ISO 9277:2022. The BET surface area measurement results are shown in Table 5.

[0350] The D10, D50, and D90 particle sizes of samples LCO-A, LCO-B, and NCM811 were measured using laser diffraction according to ISO 13320:2020. The particle lengths were measured and analyzed to obtain the particle size distribution, from which the D10, D50, and D90 values ​​were calculated. The size distribution was calculated on a volumetric basis. The results are shown in Table 5.

[0351] Equation (II) was also used to compare the D90, D50, and D10 particle sizes, which represents the proportion of the particle size distribution (the difference between the D90 and D10 particle sizes) to the D50 particle size. The “S” value in Equation (II) for each sample is shown in Table 5.

[0352] Table 5. Physicochemical properties of graphite anode (sample F) and LCO cathode samples (LCO-A and LCO-B)

[0353]

[0354] The D50 of sample LCO-A is much larger than that of LCO-B, and therefore its BET surface area is also much lower. The D50 of LCO-A is more than 4 times greater than that of graphite sample F. The D50 of LCO-B is less than 2 times greater than that of graphite sample F. The D50 of NCM811 is approximately 2.7 times greater than that of graphite sample F.

[0355] Electrode preparation

[0356] The graphite anode for sample F was prepared as described above in Example 1.

[0357] LCO cathodes were prepared by combining 95 wt.% LCO, 3 wt.% conductive carbon, and 2 wt.% PVdF to form a slurry, which was then coated onto aluminum foil. The electrodes were dried at room temperature. The dried electrodes were then calendered at room temperature to obtain a 3.6 g / cm³ electrode. 3 The rolling density.

[0358] The NCM811 cathode was prepared in the same manner.

[0359] Electrochemical characterization

[0360] The LCO electrode was evaluated using a 2025 stainless steel coin cell cell configured with a half-cell unit. The graphite working electrode (sample F) and the LCO counter electrode (LCO-A or LCO-B) were dried under vacuum at 100ºC for 3 h, then transferred to an argon-filled glove box without exposure to air. The cell unit was assembled in the glove box with the electrolyte consisting of 1.15 M LiPF6 in EC, EMC, and VC solvent (70:30:2 v / v / w). After drying under vacuum at 40ºC for 2 h and transferring to the glove box, a glass fiber diaphragm was used.

[0361] Electrochemical performance was tested by measuring the intercalation and deintercalation capacities at rates of 0.2, 0.5, 1, 2, 5, 10, and 20 C. 4.3 V was considered a full charge, and 2.8 V was considered a full discharge. Capacity retention was determined as a percentage of the initial charge capacity at 0.5 C and a percentage of the initial discharge capacity at 0.2 C.

[0362] Table 6 summarizes the electrochemical performance results.

[0363] Table 6. Capacity retention at high rates for LCO-A and LCO-B cathodes and sample F graphite anode tested in 2025 half-coin cell cells.

[0364]

[0365] Figure 5 Capacity retention (%) during charging and discharging at C-rates of 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 C-rates is also shown. Capacity retention is measured by comparing the initial charge / discharge capacity (at a C-rate of 0.2) with the charge / discharge capacity at the new C-rate.

[0366] Figure 5 The results show that LCO-B outperforms LCO-A in both charge and discharge capacity retention across all charge rates. The difference between LCO-B and LCO-A is greatest at high rates, especially at high charge rates.

[0367] The NCM811 cathode and graphite sample F anode were tested in a monolayer 12 mAh pouch cell. Long-term electrochemical performance was tested by measuring the insertion and extraction capacities at a charge rate of 12C and a discharge rate of 1C.

[0368] Figure 8 The capacity retention (compared to the initial cell capacity) after approximately 1200 cell cycles is shown. At high charge rates, the cell retains approximately 85% of its capacity after 1000 cycles.

[0369] It is considered advantageous if the fast charging rate capability of the cathode matches that of the graphite anode. This embodiment demonstrates that using smaller LCO or NCM cathode particles is more suitable for fast charging. Specifically, particle size D 50 It is the D of graphite anode material 50 The LCO cathode, which is less than three times larger, provides exceptionally fast charging and good capacity retention at high charge (discharge) rates.

[0370] References

[0371] Numerous publications have been cited above to more fully describe and disclose the invention and prior art. Full citations of these references are provided below. The entirety of each of these references is incorporated herein by reference.

[0372] CN110649256B

[0373] CN111725485B

[0374] CN112397691A

[0375] CN 113140697

[0376] US 2023 / 0016746

[0377] CN 107910483

[0378] KR 1020230131294

[0379] US 7749659

[0380] WO 2021 / 125755

Claims

1. An electrochemical cell unit having a working electrode, a counter electrode, and an electrolyte, wherein... The working electrode comprises a working electrode active material, and the working electrode active material comprises particles with a particle length D50 by volume. w Graphite particles, The counter electrode comprises a counter electrode active material, and the counter electrode active material comprises particles with a particle length D50 by volume. c Graphite particles, of which D50 w and D50 c Satisfying equation (Ia): D50 c = C 50 × D50 w (Ia) Where C 50 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

2. The electrochemical battery cell according to claim 1, wherein C 50 It is 1 to 6, preferably 1.2 to 4, more preferably 1.3 to 3, and even more preferably 1.4 to 2.

3. The electrochemical cell cell according to claim 1 or 2, wherein the working electrode active material comprises particles having a particle length D10 by volume D10. w The graphite particles, and the active material for the counter electrode comprises particles with a particle length D10 by volume D10. c Particles, of which D10 w and D10 c Satisfaction Equation (Ib): D10 c = C 10 × D10 w (One) Where C 10 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

4. The electrochemical battery cell according to claim 3, wherein C 10 It is 1 to 6, preferably 1.2 to 4, more preferably 1.3 to 3, and even more preferably 1.5 to 2.

5. The electrochemical cell cell according to any one of claims 1 to 4, wherein the working electrode active material comprises particles having a particle length D90 by volume. w The graphite particles, wherein the active material for the counter electrode comprises particles having a particle length D90 by volume D90. c The particles, and of which D90 w and D90 c Satisfaction Equation (Ic): D90 c = C 90 × D90 w (Ic) Where C 90 It is 6 or smaller, preferably 4 or smaller, more preferably 3 or smaller, and even more preferably 2 or smaller.

6. The electrochemical battery cell according to claim 5, wherein C 90 It is 1 to 6, preferably 1.1 to 4, more preferably 1.2 to 3, and even more preferably 1.2 to 2.

7. The electrochemical cell unit according to any one of claims 1 to 6, wherein the particle length distribution width S of the graphite particles is... w It is 1.6 or greater, wherein the distribution width is defined by equation (IIa): S w = (D90 w - D10 w ) / (D50 w )(Iia) Among them, D90 w and D10 w The D90 and D10 particle lengths are the graphite particles by volume.

8. The electrochemical battery cell according to claim 7, wherein S w It is 1.65 or greater, preferably 1.7 or greater, more preferably 1.75 or greater.

9. The electrochemical battery cell according to any one of claims 1 to 8, wherein the counter electrode active material comprises a particle length distribution width S. c For particles of 1.6 or smaller, the distribution width is defined by formula (Iib): S c = (D90 c - D10 c ) / (D50 c )(Iib) Among them, D90 c and D10 c The D90 and D10 particle lengths, by volume, are the active material particles for the electrode.

10. The electrochemical battery cell according to claim 9, wherein S c It is 1.5 or less, preferably 1.4 or less, more preferably 1.35 or less.

11. The electrochemical cell unit according to any one of claims 1 to 10, wherein for the graphite particles: (i) D50 w It is 1 to 20 µm, preferably 2 to 10 µm, more preferably 3 to 7 µm, and even more preferably 3.5 to 4 µm; (ii) D10 w It is 5 µm or smaller, preferably 4 µm or smaller, more preferably 3 µm or smaller, and even more preferably 2 µm or smaller; and / or (iii) D90 w It is 30 µm or smaller, preferably 20 µm or smaller, more preferably 15 µm or smaller, and even more preferably 9 µm or smaller.

12. The electrochemical cell unit according to any one of claims 1 to 11, wherein the graphite particles have: (i) 0.8 g / cm 3 Or smaller, preferably 0.7 g / cm³ 3 or smaller, more preferably 0.65 g / cm 3 or smaller tap density; and / or (ii) 1.2 to 1.8 g / cm³ 3 Preferably, the concentration is 1.3 to 1.6 g / cm³. 3 The rolling density.

13. The electrochemical cell unit according to any one of claims 1 to 12, wherein the BET surface area of ​​the graphite particles is 4 m². 2 / g or greater, preferably 5 m 2 / g or greater, more preferably 6 m 2 / g or greater, where the BET surface area is measured according to ISO 9277:2022.

14. The electrochemical battery cell according to any one of claims 1 to 13, wherein the electrode active material comprises graphite particles having a bimodal particle length distribution.

15. The electrochemical cell cell according to claim 14, wherein the first group of graphite particles has a first mode particle length of 2 to 6 µm, more preferably 3 to 5 µm, and even more preferably 3.5 to 4 µm, and the second group of graphite particles has a second mode particle length of 6 to 10 µm, more preferably 7 to 9 µm, and even more preferably 7.5 to 8 µm.

16. The electrochemical cell cell according to claim 14 or 15, wherein the first group of graphite particles has a particle length D50 by volume. w1 The second group of graphite particles has a particle length D50 by volume. w2 D50 w1 and D50 w2 Satisfying equation (IIIa): D50 w1 = E 50 × D50 w2 (IIIa) Where E 50 It is 3 or smaller, preferably 2.5 or smaller, more preferably 2 or smaller.

17. The electrochemical cell unit according to claim 16, wherein E 50 It is 1 to 3, preferably 1.5 to 2.5, and more preferably 1.8 to 2.

2.

18. The electrochemical cell cell according to any one of claims 1 to 17, wherein for the particles of the counter electrode active material: (i) D50 c It is 2 to 50 µm, preferably 3 to 30 µm, more preferably 4 to 20 µm, and even more preferably 5 to 10 µm; (ii) D10 c It is 8 µm or smaller, preferably 6 µm or smaller, more preferably 5 µm or smaller, and even more preferably 4 µm or smaller; and / or (iii) D90 c It is 6 to 80 µm, preferably 8 to 60 µm, more preferably 9 to 40 µm, and even more preferably 10 to 15 µm.

19. The electrochemical battery cell according to any one of claims 1 to 18, wherein the active material particles of the counter electrode are lithium cobalt oxide (LCO), lithium nickel manganese cobalt oxide (NMC), nickel cobalt aluminum oxide (NCA), or a combination thereof, preferably LCO, NCM, or a combination thereof.

20. The electrochemical cell cell according to any one of claims 1 to 19, wherein the working electrode and / or the counter electrode comprises a binder, wherein the binder is PVDF, CMC, SBR, or a mixture thereof, preferably wherein the binder comprises a mixture of CMC and SBR.

21. The electrochemical cell cell according to any one of claims 1 to 20, wherein, based on the total mass of the working electrode, the working electrode and / or the counter electrode comprises 90 wt.% or more, preferably 94 wt.% or more, more preferably 96 wt.% or more of electrode active material particles.

22. The electrochemical battery cell according to any one of claims 1 to 21, further comprising a separator.

23. The electrochemical battery cell according to any one of claims 1 to 22, wherein the electrochemical battery cell is rechargeable and / or dischargeable, such as rechargeable, at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

24. A method for charging and / or discharging an electrochemical battery cell according to any one of claims 1 to 23 at a C-rate of 5C or greater, preferably 10C or greater, more preferably 20C or greater.

25. The method of claim 24, wherein the method comprises cycling the electrochemical cell unit to charge and discharge, and (i) After 1000 cycles at a C-rate of 1C, the discharge capacity retention is 90% or greater, and / or (ii) After 2000 cycles at a charge rate of 6C and a discharge rate of 1C, the specific discharge capacity retention is 80% or greater.

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