Phosphate-based conductive composite particle with dopamine and PVDF layer

Abstract

Phosphate-based conductive composite particle with a dopamine and a PVDF layer. The conductive composite particle is used in the electrode ground layer of a solid-state or semi-solid-state battery.The conductive composite particle comprises: a ceramic particle with high lithium ion conductivity, which conducts lithium ions through the electrode, so that the lithium ion channels are widely distributed throughout the electrode, thus providing evenly distributed lithium ion channels; a dopamine layer surrounding the outer surface of the ceramic particle; the dopamine layer consists of a plurality of copolymerized dopamine molecules; the dopamine layer and the corresponding ceramic particle form a second composite particle; a PVDF (polyvinylidene fluoride) layer is applied to the outer surface of the second composite particle; the PVDF layer consists of multiple PVDFs; the PVDF layer and the corresponding second composite particle form the conductive composite particle. The dopamine layer does not completely surround the outer surface of the ceramic particles, so that parts of the outer surface of the ceramic particle are exposed.As a result, parts of the PVDF layer touch the surface of the ceramic particle, while others touch the dopamine layer. Some of the fluoride ions (F-) in the PVDFs are ionically bonded to the lithium ions (Li-) on the outside of the ceramic particle, forming lithium fluoride (LiF). Another part of the fluoride ions (F-) in the PVDFs are hydrogen-bonded to nitrogen ions (N-) of the dopamine on the outside of the second composite particle. The PVDFs therefore form a PVDF layer that encloses the outside of the second composite particle.

Description

AREA OF INVENTION

[0001] The present invention relates to positive electrode particles and in particular a phosphate-based conductive composite particle with a dopamine and a PVDF layer. BACKGROUND OF THE INVENTION

[0002] A typical battery consists primarily of positive and negative electrodes placed in the electrolyte. In current technology, ceramic particles are added to the electrode to increase its ionic conductivity. Since the ceramic particles exhibit high lithium-ion conductivity, the lithium-ion channels within the electrode can be distributed by guiding the dispersed ceramic particles as the lithium ions pass through, resulting in a uniform distribution of lithium-ion channels throughout the electrode body. Conventionally, the surface of the ceramic particles contains many alkaline functional groups (such as OH-, Li₂O, etc.).Therefore, the positive electrode material added during electrode production exhibits strong alkalinity due to the reaction between the ceramic particles and the solvent. This leads to deterioration of the positive electrode particles within the electrode material and of the electrode material itself, complicating the manufacturing process and likely resulting in lower-than-expected electrochemical properties of the manufactured positive electrode plate. It is known from the prior art that ceramic particles can be protected by coating their outer surface with a dopamine layer. However, the dopamine layer cannot completely enclose the outer surface of the ceramic particles, leaving parts of the outer surface exposed.When several ceramic particles coated with dopamine layers are added to the electrode compound according to the current state of the art, exposed parts of the second composite particle react with the solvent in the electrode compound, causing the electrode compound to become highly alkaline. However, high alkalinity is detrimental to battery quality; therefore, a new solution to improve this deficiency is a logical step. SUMMARY OF THE INVENTION

[0003] To overcome the aforementioned shortcomings of the prior art, the object of the present invention is to provide a phosphate-based conductive composite particle comprising a dopamine layer and a PVDF layer, wherein a further PVDF layer is arranged on the outside of the ceramic particle originally enclosed by a dopamine layer as a protective layer. The PVDF layer thus provides additional protection to the second composite particle, preventing it from reacting with the solvent in the positive electrode mass and damaging it. BRIEF DESCRIPTION OF THE INVENTION Fig. shows a cross-sectional view illustrating the structure of the invention. Fig. shows an application of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0004] With regard to the Fig. The present invention provides a phosphate-based conductive composite particle with a dopamine layer and a PVDF layer. The conductive composite particle 100 is used in an electrode 10 of a solid-state or semi-solid battery. In particular, the electrode 10 represents a positive electrode of a solid-state or semi-solid battery. The electrode 10 contains an electrode substrate 11 as a carrier for the electrode material and an electrode mass layer 13 coated onto the electrode substrate 11. The electrode mass layer 13 comprises several conductive particles 100 and an electrode mass 12 with a binder. The weight fraction of the conductive composite particle 100 in the electrode mass layer 13 is between 2 wt% and 10 wt%, where wt% indicates weight percent. The particle size of each conductive composite particle 100 is less than 300 nm. Fig. The conductive composite particle 100 contains the following component: a ceramic particle 15 with a particle size of less than 100 nm. The ceramic particle 15 exhibits high lithium-ion conductivity and conducts lithium ions through the electrode 10, thereby distributing lithium-ion channels within the electrode 10. This ensures a uniform distribution of the lithium-ion channels within the electrode 10. Side reactions with the electrode suspension 12 in the electrode 10, which would otherwise result from abnormal lithium ion deposition in the electrode suspension 12, are avoided. The ceramic particle 15 consists of at least one of the following materials: ceramic oxide, garnet-structured oxide, or perovskite-structured oxide. The lithium-ion conductivity of the ceramic oxide is greater than 10 -5 cm 2 / s (diffusion coefficient). The ceramic oxide consists of LAGP (lithium aluminum germanium phosphate) with a NASICON structure (sodium (Na) superion conductor). The garnet-structured oxide can be LLZO (Li7La3Zr2O). 12 The ceramic particle 15 can be lithium lanthanum zirconium oxide or the perovskite oxide LLTO (lithium lanthanum titanium oxide). The ceramic particle 15 can be formed by combining the above-mentioned materials in any desired ratio. Furthermore, the ceramic particle 15 can consist of at least one of the following materials: LLZO (Li7La3Zr2O) 12 ), Ga-LLZO (gallium-doped LLZO), Cu-LLZO (copper-doped LLZO), Ta-LLZO (tantalum-doped LLZO), Sr-LLZO (strontium-doped LLZO) or Al-LLZO (aluminium-doped LLZO). If the ceramic particle 15 consists of LAGP, the LAGP is made of Li 1+x Al x Ge 2-x (PO4)3 or Li 1+x+y Al x Ge 2-x-y-z M y N z(PO4)3 selected where 0.1≤x≤0.8, 0≤y≤0.2, 0≤z≤0.2, M a trivalent cation (such as scandium cation (Sc 3+ ), Yttrium cation (Y 3+ ), Gallium cation (Ga 3+ ), Indium cation (In 3+ ) or lanthanum cation (La 3+ )) and N a tetravalent cation (such as zirconium cation (Zr) 4+ ), silicon cation (Si 4+ ) or tin cation (Sn 4+ )) is. A dopamine layer 35 surrounds an outer surface of the ceramic particle 15. The dopamine layer 35 consists of several copolymerized dopamine molecules. As in Fig. As shown, the dopamine layer 35 and the associated ceramic particle 15 form a second composite particle 110. The mechanism by which the copolymerized dopamine molecules bond with the ceramic particle 15 is known and therefore will not be explained in detail here. For example, it could be a dehydrated copolymerization reaction in which an OH ion binds to the ceramic particle 15 and links to the OH bond of the dopamine layer 35. The OH ion is connected to the ceramic particle 15 via a hydrogen bond.

[0005] A PVDF (polyvinylidene fluoride) layer 41 is applied to the outer surface of the second composite particle 110. The PVDF layer 41 consists of several PVDFs. As shown in Fig.The PVDF layer 41 and the corresponding second composite particle 110 are shown to form the conductive composite particle 100. The dopamine layer 35 is between 2 nm and 15 nm thick, and the PVDF layer 41 is between 10 nm and 100 nm thick. However, the surface of the ceramic particles exhibits many alkaline functional groups (such as OH-, Li₂O, etc.). Therefore, during electrode fabrication, when the ceramic particles are added to the positive electrode mass, the mixture becomes highly alkaline due to the reaction between the ceramic particles and the solvent. This leads to a deterioration in the quality of the positive electrode particles and the positive electrode mass itself, complicating the fabrication process and resulting in poorer electrochemical properties of the fabricated positive electrode plate.In the prior art, it is known that ceramic particles are protected by coating their outer surface with the dopamine layer 35. However, the dopamine layer 35 cannot completely enclose the outer surface of the ceramic particles, so that parts of the outer surface remain exposed. In the present invention, the dopamine layer 35 also does not completely enclose the outer surface of the ceramic particles, so that parts of the outer surface remain exposed. Consequently, parts of the PVDF layer 41 contact the surface of the ceramic particles 15, while other parts of the PVDF layer 41 contact the dopamine layer 35. When the ceramic particles enclosed by the dopamine layer 35 (referring to the second composite particle 110 mentioned above) are added to the positive electrode, the electrode material reacts with exposed parts of the second composite particle 110 and the solvent of the positive electrode material, making it strongly alkaline.Therefore, in the present invention, the outer surface of the second composite particle 110 is additionally enclosed with a PVDF layer 41 to provide further protection. This prevents it from reacting with the solvent of the positive electrode material and consequently does not impair its quality. Some of the fluoride ions (F-) in the PVDFs are bound to the lithium ions (Li-) on the outer surface of the ceramic particle 15 by ionic bonding, forming lithium fluoride (LiF). Another portion of the fluoride ions (F-) in the PVDFs are bound to nitrogen ions (N-) of the dopamine on the outer surface of the second composite particle 110 via hydrogen bonds. Thus, the PVDFs form the PVDF layer 41, which encloses the outer surface of the second composite particle 110.

[0006] A phosphate-based conductive composite particle thus consists of a dopamine layer and a PVDF layer. This conductive composite particle is used in the electrode mass layer of a solid-state or semi-solid-state battery. The conductive composite particle comprises a ceramic particle with high lithium-ion conductivity, which conducts lithium ions through the electrode, resulting in widely distributed lithium-ion channels and thus a uniformly distributed lithium-ion channel structure; a dopamine layer encasing the outer surface of the ceramic particle; this dopamine layer consists of several copolymerized dopamine molecules; the dopamine layer and the corresponding ceramic particle form a second composite particle; and a PVDF (polyvinylidene fluoride) layer applied to the outer surface of this second composite particle; the PVDF layer consists of multiple PVDFs.In describing the present invention, it is obvious that it can be varied in many ways. Such variations do not constitute a departure from the inventive concept, and all modifications obvious to a person skilled in the art fall within the scope of the following claims.

Claims

[1] Phosphate-based conductive composite particle with a dopamine and a PVDF layer. The conductive composite particle is used in the electrode mass layer of a solid-state or semi-solid battery.The conductive composite particle comprises: a ceramic particle with high lithium-ion conductivity, which conducts lithium ions through the electrode, resulting in widely distributed lithium-ion channels within the electrode; a dopamine layer encasing the outer surface of the ceramic particle; the dopamine layer consists of numerous copolymerized dopamine molecules; the dopamine layer and the corresponding ceramic particle form a second composite particle; a PVDF (polyvinylidene fluoride) layer is applied to the outer surface of the second composite particle; the PVDF layer consists of multiple PVDFs; the PVDF layer and the corresponding second composite particle form the conductive composite particle. The dopamine layer does not completely encase the outer surface of the ceramic particle, leaving portions of the ceramic particle's outer surface exposed.As a result, parts of the PVDF layer contact the surface of the ceramic particle, while other parts contact the dopamine layer. Some of the fluoride ions (F-) in the PVDFs are bonded to the lithium ions (Li-) on the outer surface of the ceramic particle via ionic bonding, forming lithium fluoride (LiF). Another portion of the fluoride ions (F-) in the PVDFs are bonded via hydrogen bonds to the nitrogen ions (N-) of the dopamine on the outer surface of the second composite particle. The PVDFs therefore form a PVDF layer that surrounds the outer surface of the second composite particle. [2] Phosphate-based conductive composite particle with a dopamine and PVDF layer according to claim 1, wherein the particle size of the conductive composite particle is less than 300 nm. [3] Phosphate-based conductive composite particle with a dopamine and a PVDF layer according to claim 1, wherein the weight fraction of the conductive composite particle in the electrode mass layer is between 2 and 10 weight percent. [4] Phosphate-based conductive composite particles with a dopamine and a PVDF layer according to claim 1, wherein the ceramic particle has a particle size of less than 100 nm. [5] Phosphate-based conductive composite particle with the dopamine and PVDF layer according to claim 1, wherein the ceramic particle consists of at least one of the following materials: ceramic oxide, garnet-structured oxide or perovskite-structured oxide; and the lithium ion conductivity of the ceramic oxide is higher than 10 -5 cm 2 / s (diffusion coefficient) is. [6] Phosphate-based conductive composite particles with a dopamine and a PVDF layer according to claim 5, wherein the ceramic oxide is LAGP and consists of Li 1+xAl x Ge 2-x (PO4)3 or Li 1+x+y Al x Ge 2-x-y-z M yN -(PO4)3 is selected, where 0.1≤x≤0.8, 0≤y≤0.2, 0≤z≤0.2 and M is a trivalent cation and N is a tetravalent cation. [7] Phosphate-based conductive composite particles with a dopamine and a PVDF layer according to claim 6, wherein the trivalent cation is a scandium cation (Sc 3+ ), Yttrium cation (Y 3+ ), Gallium cation (Ga 3+ ), Indium cation (In 3+ ) and lanthanum cation (La 3+ ); and the tetravalent cation is selected from the zirconium cation (Zr). 4+ ), silicon cation (Si 4+ ) or tin cation (Sn 4+ ) is selected. [8] Phosphate-based conductive composite particles with a dopamine and a PVDF layer according to claim 1, wherein the thickness of the dopamine layer is between 2 nm and 15 nm. [9] Phosphate-based conductive composite particles with a dopamine and a PVDF layer according to claim 1, wherein the thickness of the PVDF layer is between 10 nm and 100 nm.

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