Cathode active material blend

Abstract

The present disclosure concerns a cathode active material blend comprising a lithium rich transition metal oxide LixMnyNizCotO2 wherein 1.05 ≤ x ≤ 2.0; 0.5 ≤ y ≤ 1.0; 0 < z ≤ 0.5; 0 ≤ t ≤ 0.1 and Fe1-qMnqPO4, wherein 0 ≤ q ≤ 0.8, wherein the mass ratio MR of Fe1-qMnqPO4 to lithium rich transition metal oxide ranges from 1:99 to 50:50. The present disclosure further concerns a cathode, and a battery incorporating this cathode active material blend.

Description

DescriptionTitleCathode active material blendTechnical Field

[0001] The present disclosure concerns a cathode active material blend comprising a lithium rich transition metal oxide LixMnyNizCotO2 and Fei.qMnqPO4, a cathode for a lithium ion secondary battery comprising the cathode active material blend and a battery comprising such a cathode.Description of related art

[0002] Energy storage systems such as rechargeable batteries are necessary for quickly storing and releasing high amounts of energy to adjust power output to demand. The same battery technology goes into electric vehicles, which run on stored electrical energy and reduce pollution compared to conventional vehicles with internal combustion engines. To meet proper demands, these batteries need to store high levels of energy with minimal weight, charge and discharge at fast rates, and go through many cycles without diminishing in performance. These requirements are respectively referred to as high energy density, rate capability, and cyclability, and the demands must be reached while the batteries remain affordable and safe. Particularly because of their high energy density and rate capability, many kinds of lithium-ion batteries (LIBs) are widely studied to meet these needs. The capacity and energy density of LIBs however remains limited by the available cathode active materials.

[0003] Lithium-rich transition metal oxide is one promising cathode active material for lithium-ion batteries due to its low cost originated from relatively lower Co content. However, batteries based on these oxides present low initial coulombic efficiency (ICE) and high irreversible capacity losses upon the first cycling. A low ICE, that is a low ratio of the charge extracted from a battery during its first discharge cycle to the charge input during the first charge cycle indicates that a smaller proportion of the charge input is utilized effectively, which is not desirable for battery efficiency and longevity. This also means that a large anode is necessary for the first charge cycle and that this anode is not used to its full extent in subsequent cycles, leading ultimately to a low volumetric capacity of the battery.

[0004] Z. Wang et al. I Journal of Power Sources 236 (2013) 25-32 disclose a FePO4 coated Li1.2Mn0.4Ni0.13Co0.13O2 cathode material showing ICE value of 85.1%. However such coating processes are relatively complicated and the ICE value is still limited.Summary

[0005] The present disclosure concerns a cathode active material blend comprising a lithium rich transition metal oxide LixMnyNizCotO2 wherein 1.052.0; 0.51.0 ; 0 =£ z =£ 0.5; 0 0.1 and Fei.qMnqPO4 wherein 0qs= 0.8; wherein the mass ratio of Fei. qMnqPC>4 to lithium rich transition metal oxide ranges from 1:99 to 60:40.

[0006] The inventors have found that in a lithium secondary battery such a cathode active material blend yields significantly increased ICE values. Thus a larger proportion of the charge input is utilized effectively, which is desirable for battery efficiency. Furthermore the anode may be used to a fuller extent leading therefore to a higher volumetric capacity of the battery.

[0007] The present disclosure further concerns a cathode for a secondary battery comprising a current collector, a cathode material layer disposed on the current collector, the cathode material layer comprising a. a cathode active material blend according to an embodiment or combination of embodiments of the present disclosure; b. at least one binder; and c. at least one carbon conductive agent.

[0008] The present disclosure further concerns a lithium ion secondary battery, comprising: a. a cathode, b. an anode, c. a separator film, and d. an electrolyte, wherein the cathode is a cathode for a secondary battery according to an embodiment or combination of embodiments of the present disclosure.Brief description of the figures

[0009] Fig 1. XRD image of examples and comparative examples. LFP = LiFePO4, HLM = lithium rich transition metal oxide, FP = FePO4 .

[0010] Fig 2. Charge-discharge curve of examples and comparative examplesDetailed description

[0011] The term "about" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / -20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1 % or less of and from the specified value, in so farsuch variations are appropriate to perform in the present disclosure. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed.

[0012] As used herein, the term “and / or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items, can be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0013] “at%” signifies atomic percentage. The at% or “atomic percent” of a given element means a percentage of atoms of said element among all atoms in a claimed composition. Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) provides weight percent (wt%) of each element included in a material whose composition is determined by this technique. Conversion from wt% to at%, as is well known to the person skilled in the art, is as follows: at% of a first element Ei (Eati) in a material can be converted from a given wt% of said first element Ei (Ewti) in said material by applying the following formula,b. wherein Eawiis a standard atomic weight (molecular weight) of the first element Ei, Ewti is wt% of an Ithelement Ei, EaWiis a standard atomic weight (molecular weight) of said Ithelement Ei, and n is an integer which represents the number of types of all elements included in the material.

[0014] Here within a range “from X to Y” or “between X and Y” includes the endpoints X and Y.

[0015] The terms “comprises”, “comprising” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0016] “D50” as used herein refers to a particle size at 50% of cumulative volume% distribution when measured by laser scattering method. The method of measuring D50 by laser scattering method is described herein below.

[0017] In the following detailed description, preferred embodiments are described in detail to enable practice of the present disclosure. Although the present disclosure is described withreference to these specific preferred embodiments, it will be understood that the present disclosure is not limited to these preferred embodiments. To the contrary, the present disclosure includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description. Unless otherwise indicated, it is not meant that the alternatives, modifications, and equivalents described herein are understood as separate, non-combinable, embodiments. That is, provided it is technically feasible, the different parts of the present disclosure may be combined with one another.

[0018] In the cathode active material blend of the present disclosure, x may range from 1.05 to 1.4.

[0019] In the cathode active material blend of the present disclosure, y may range from 0.5 to 0.75.

[0020] In the cathode active material blend of the present disclosure, z may range from 0.25 to 0.5.

[0021] In the cathode active material blend of the present disclosure, t may range from 0 to 0.05.

[0022] In the cathode active material blend of the present disclosure, Fei.qMnqPO4 may be such that 0 < qs= 0.8. The presence of Mn may lead to an increase of energy density of the blend.

[0023] In the cathode active material blend of the present disclosure, the mass ratio MR of Fei. qMnqPO4 to lithium rich transition metal oxide ranges from 1 :99 to 50:50; Increasing the relative amount of Fei-qMnqPC>4 reduces the specific capacity of the first charge cycle, while increasing the ICE value. Preferably MR is at least 10:90, more preferably at least 20:80 to have a significant impact on ICE. Advantageously, MR is not more than 50:50, advantageously not more than 45:55, not more than 40:60, not more than 35:65, not more than 30:70, or not more than 25:75 in order to retain a higher specific capacity. Furthermore MR may be adapted in order to keep ICE at a value of about 100%.

[0024] In the cathode active material blend of the present disclosure the lithium rich transition metal oxide has a particle size distribution (PSD) value D50 ranging from 1 pm to 20 pm, alternately from 1.5 pm to 15 pm, alternately form 2 pm to 15 pm. The lithium rich transition metal oxide may essentially be a powder. The particle size distribution of this powder may be measured in particular by laser diffraction particle size analysis. PSD value D50 is defined as the particle size at 50% of the cumulative volume% distributions.

[0025] In the secondary battery cathode of the present disclosure, the cathode active material layer may have a thickness of 10 pm to 250 pm. Thinner cathode layers (closer to 10 pm) may facilitate faster ion transport and better rate capability due to reduced diffusion distances, but may limit the total amount of active material and thus reduce overall capacity. Thicker cathode layers (up to 250 pm) allow for more active material, potentially increasing energy density, but may suffer from slower ion diffusion and reduced rate performance, especially at high charge / discharge rates.

[0026] In the secondary battery cathode of the present disclosure, the cathode active material layer may comprise, relative to the total weight of the cathode active material layer, 1 wt% to 10 wt% of one or more carbon conductive agents , 1 wt% to 10 wt% of one or more binders, and 80 wt% to 95 wt% of cathode active material blend.

[0027] In the secondary battery cathode of the present disclosure, the cathode active material layer may comprise, relative to the total weight of the cathode active material layer, 1 wt% to 10 wt% of one or more carbon conductive agents, in particular selected from acetylene black, conductive carbon black, carbon fiber, carbon nanotube, and / or ketjen black.

[0028] In the secondary battery cathode of the present disclosure, the cathode active material layer may comprise, relative to the total weight of the cathode active material layer, 1 wt% to 10 wt% of one or more binders in particular selected from polyvinyl alcohol, polyurethane, polyacrylate, polyvinylidene fluoride, styrene butadiene rubber, epoxy resin, vinyl acetate resin and chlorinated rubber.

[0029] In the lithium ion secondary battery of the present disclosure, the anode may comprise a current collector comprising soft carbon, hard carbon, artificial graphite, natural graphite, silicon, a silicon oxy compound, a silicon carbon composite, lithium titanate, lithium and / or one or more of metals capable of forming an alloy with lithium. Lithium titanate, lithium, and alloys of lithium with one or more of metals capable of forming an alloy with lithium may advantageously provide additional lithium ions and thus more lithium may be introduced to the cathode during discharge than was extracted during its first charge, possibly leading to ICE values exceeding 100%.

[0030] In the lithium ion secondary battery of the present disclosure, the electrolyte may comprise a solvent comprising one or more solvents selected from ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and one or more solutes selected from LiPFe, LiBF4, LiBOB, LiAsFe, Li(CF3SC>2)2N, LiCF3SC>3, and LiCICL.

[0031] In the lithium ion secondary battery of the present disclosure, the separator film may comprises one or more selected from polyethylene, polypropylene, nonwoven fabric, and polyfiber material.

[0032] The present disclosure further concerns the use of the battery of the present disclosure comprising a cathode active material in an electrically powered device or system selected from the group consisting of: a portable computer, a tablet, a mobile phone, a telecommunication device, a power tool, mobile machinery, a robotic device, an energy storage system, an uninterruptible power supply system, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an extended-range electric vehicle, a fuel cell electric vehicle, a two-wheeler transportation system, a rail vehicle, a marine vessel, an aircraft, an aerospace system.

[0033] The use of the battery of the present disclosure comprising a cathode active material in the above-listed electrically powered devices and systems enables efficient and reliable energy delivery across a wide range of operational environments. The integration of such batteries into consumer electronics (e.g., portable computers, tablets, mobile phones, telecommunication devices) provides compact and lightweight energy sources that support high energy density and long operational life, thereby enhancing user experience and device portability.

[0034] In industrial applications such as power tools, mobile machinery, and robotic devices, the battery enables high discharge rates and robust performance under variable load conditions, contributing to improved productivity and operational flexibility. The use in energy infrastructure systems, including energy storage systems and uninterruptible power supply (UPS) systems, ensures stable and scalable energy management, supporting grid resilience and backup power reliability.

[0035] In transportation systems, the battery supports electrification of mobility platforms, including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), extended-range electric vehicles (EREVs), and fuel cell electric vehicles (FCEVs). These applications benefit from the battery’s ability to deliver consistent power output, fast charging capability, and thermal stability, which are critical for safety and performance in both passenger and freight transport. The inclusion of two-wheeler transportation systems, rail vehicles, marine vessels, aircraft, and aerospace systems demonstrates the versatility of the battery across diverse propulsion architectures and regulatory environments.EXAMPLES and EXPERIMENTAL TESTS

[0036] The invention is described below in greater details with reference to examples, but the invention is not limited in any way by these examples, as long as it does not exceed the scope and spirit of the present invention. The following analysis are used in all Examples.

[0037] Powder X-ray Diffraction (XRD). XRD patterns are recorded on a Bruker D8 Advance A25 X-ray diffractometer in the 3-352-theta range. Scan speed is set to 0.02 degrees per 5 seconds. The collected XRD patterns comprise KAIpha Mo radiations with typical wavelengths KAIphal =0.7093 A. The incident beam optic setup comprises a 6-degree divergence slit (DS) and 2.5 degree vertical Soller slit. The diffracted beam optic setup includes a 2.5 degree vertical Soller slit. The detector used is a LYNXEYE XE-T (1D mode) with a 4.075 degrees PSD opening. To prevent fluctuations the temperature is kept near room temperature all the time.

[0038] Coin cell preparation. The method comprises forming a slurry comprising a positive electrode active material powder, a conductive material (carbon black, C65, Imerys), and a binder (PVDF, Solvay) in a weight ratio of 84:8.0:8.0, respectively, in a solvent (NMP, Thermo Fisher). The slurry is homogenized using a disperser (IKA UltraTurrax T25). A small amount of pure cathode active material blend is added to the slurry during stirring to reduce the viscosity. The homogenized slurry is then uniformly applied to one side of an aluminum foil substrate using a doctor blade coater with a gap of 250 pm. The coated foil is subsequently dried in a vacuum oven at a temperature of 70 °C under vacuum condition overnight. Following the drying step, the coated foil is pressed by a 14 mm disk using a calendaring tool and then subjected to a second drying process in a vacuum oven at a temperature of 120 °C for 2 h to ensure complete removal of the solvent from the electrode film.

[0039] The coin cell is assembled within an argon-filled glovebox to prevent contamination. A separator (Whatman glass fiber filter) is placed between the positive electrode and a piece of lithium foil, which serves as the negative electrode. An electrolyte solution comprising 1M LiPFe in a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 1:1 is added between the separator and the electrodes. The coin cell is then sealed to prevent electrolyte leakage, completing the assembly process.

[0040] Coin cell testing method. The tests for discharge capacity (DQ) and irreversible capacity (Qirr) are performed using an MOG2 potentiostat-galvanostat (Bio-logic). The electrode loading is approximately 9.5 mg / cm2. The discharge capacity for the first cycle (DQ1) is measured within the voltage range of 4.7-2.0 V at a rate of 1C (expressed in mAh / g) at a temperature of 25°C.

[0041] Example 1. A positive electrode active material labelled as EX1 is prepared according to the following steps: a. Step 1) LFP delithiation: 5 g of LiFePC>4 is mixed with 15.09 g of sodium persulfate at room temperature overnight. The mixture is then washed, filtered, and dried at 70 °C overnight. b. Step 2) Blending: the dried mixture from step 1) is mixed with Lii.i25Nio.3i2Mno.56302 (D50=7 pm) in a mass ratio of 10:90 to obtain EX1.

[0042] The prepared examples, EX1 , are analyzed using X-ray Diffraction (XRD) and coin cell test to evaluate their characteristics, and electrochemical performance.

[0043] Example 2. A positive electrode active material labelled as EX2 is prepared according to the following steps: a. Step 1) LFP delithiation: 5 g of LiFePC>4 is mixed with 15.09 g of sodium persulfate at room temperature overnight. The mixture is then washed, filtered, and dried at 70 °C overnight. b. Step 2) Blending: the dried mixture from step 1) is mixed with Lii.i25Nio.3i2Mno.56302 (D50=7 pm) in a mass ratio of 25:75 to obtain EX2.

[0044] The prepared examples, EX2, are analyzed using X-ray Diffraction (XRD) and coin cell test to evaluate their characteristics, and electrochemical performance.

[0045] Example 3. A positive electrode active material labelled as EX3 is prepared according to the following steps: a. Step 1) LFP delithiation: 5 g of LiFePC>4 is mixed with 15.09 g of sodium persulfate at room temperature overnight. The mixture is then washed, filtered, and dried at 70 °C overnight. b. Step 2) Blending: the dried mixture from step 1) is mixed with Lii.i25Nio.3i2Mno.56302 (D50=7 pm) in a mass ratio of 50:50 to obtain EX3.

[0046] The prepared examples, EX3, are analyzed using X-ray Diffraction (XRD) and coin cell test to evaluate their characteristics, and electrochemical performance.

[0047] Comparative example 1. A positive electrode active material labelled as CEX1 comprised only of a material having a formula of Lii.i25Nio.3i2Mno.56302.

[0048] The prepared examples, CEX1 , are analyzed using X-ray Diffraction (XRD) and coin cell test to evaluate their characteristics, and electrochemical performance.

[0049] The summary of the blending process for the examples and comparative examples can be found in Table 2. Figure 1 shows that during blending there is no formation of LiFePC>4 (LFP) as there are no corresponding peaks in the XRD.

[0050] Table 1. Summary of the blending process for the preparation of positive electrode active material.

[0051] Table 2. Summary of the electrochemical properties of examples and comparative examples

[0052] Table 2 summarizes the electrochemical properties with variation in the blend ratio. It could be observed that when introducing a lower specific capacity material like FePC>4 (170 mAh / g) into a high lithium manganese-based electrode active material, the overall specific capacity decreases accordingly yet at the same time the efficiency of the cycle increases dramatically and can even surpass 100% meaning that during the first cycle, more lithium was introduced to the positive electrode during discharge than extracted during its first charge. This is possible due to the lithium metal negative electrode providing a quasi-infinite lithium reservoir.

[0053] Figure 2 illustrates the initial cycle performance for all tested examples, highlighting both the first-cycle coulombic efficiency and the corresponding discharge specific capacity. Across all electrode samples, a high-voltage plateau is observed near 4.6 V, characteristic of the high-lithium manganese-based active material. During discharge, a second plateau appears around 3.45 V, corresponding to the LiFeP04level. Between these voltage regions, a sloped voltage profile is evident. As the proportion of FeP04increases within the blend, its electrochemical signature becomes increasingly prominent.

Claims

Claims

1. Cathode active material blend comprising a lithium rich transition metal oxide LixMnyNizCotO2 wherein 1.052.0; 0.51.0 ; 0 < z =£ 0.5; 0 =£ t =£ 0.1 andFei-qMnqPO4, wherein 00.8 , wherein the mass ratio MR of Fei.qMnqPC>4 to lithium rich transition metal oxide ranges from 1:99 to 50:50.

2. Cathode active material blend according to claim 1 wherein MR is at most 45:55, at most 40:60, at most 35:65, at most 30:70, or at most 25:75.

3. Cathode active material blend according to any one preceding claim wherein 1.05 5= x 5= 1.4.

4. Cathode active material blend according to any one preceding claim wherein 0.5 $ y $ 1.0.

5. Cathode active material blend according to any one preceding claim wherein 0.25 0.5.

6. Cathode active material blend according to any one preceding claim wherein 0 0.05.

7. Cathode active material blend according to any one preceding claim wherein the lithium rich transition metal oxide has a particle size distribution value D50 ranging from 1 pm to 20 pm, preferably from 1.5 pm to 15 pm.

8. Cathode for a secondary battery comprising a. a current collector; b. a cathode material layer disposed on the current collector, the cathode material layer comprising : i. a cathode active material blend according to any one of claims 1 to 7; ii. at least one binder; and iii. at least one carbon conductive agent.

9. Cathode according to claim 8, wherein the cathode active material layer has a thickness of 10 pm to 250 pm.

10. Cathode according to claim 8 or claim 9, wherein the cathode active material layer comprises relative to the total weight of the cathode active material layer:a. 1 wt% to 10 wt% of one or more carbon conducive agents, selected from acetylene black, conductive carbon black, carbon fiber, carbon nanotube, and ketjen black; b. 1 wt% to 10 wt% of one or more binders selected from polyvinyl alcohol, polyurethane, polyacrylate, polyvinylidene fluoride, styrene butadiene rubber, epoxy resin, vinyl acetate resin and chlorinated rubber; and c. 80 wt% to 95 wt% of cathode active material blend.

11. A lithium ion secondary battery, comprising: a. a cathode, b. an anode, c. a separator film, and d. an electrolyte, wherein the cathode is a cathode according to any one of claims 8 to 10.

12. Lithium ion secondary battery according to claim 11, wherein the anode comprises a current collector comprising soft carbon, hard carbon, artificial graphite, natural graphite, silicon, a silicon oxy compound, a silicon carbon composite, lithium titanate, lithium and / or one or more of metals capable of forming an alloy with lithium.

13. Lithium ion secondary battery according to claim 12, wherein the electrolyte comprises a solvent comprising one or more solvents selected from ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and one or more solutes selected from LiPFe, LiBF4, LiBOB, LiAsFe, Li(CF3SC>2)2N, LiCF3SC>3, and LiCICL.

14. Lithium ion secondary battery according to claim 12 or claim 13, wherein the separator film comprises one or more selected from polyethylene, polypropylene, nonwoven fabric, and polyfiber material.

15. Use of a battery according to any one of claims 11 to 14 in an electrically powered device or system selected from the group consisting of: a portable computer, a tablet, a mobile phone, a telecommunication device, a power tool, mobile machinery, a robotic device, an energy storage system, an uninterruptible power supply system, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an extended- range electric vehicle, a fuel cell electric vehicle, a two-wheeler transportation system, a rail vehicle, a marine vessel, an aircraft, and an aerospace system.

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