Single-layer dielectric thin film with ceramic particles embedded in organic material in a battery structure

Abstract

A single-layer dielectric thin film with ceramic particles embedded in organic material in a battery structure; wherein a solid or semi-solid lithium battery comprises a negative electrode, a positive electrode, and the dielectric thin film layer connected between the negative electrode and the positive electrode; A dielectric thin film comprising: A polymer material as a base material for the dielectric thin film consisting of a mixture of PVDF-HFP (polyvinylidene fluoride hexafluoropropylene copolymer), HNBR (hydrogenated nitrile butadiene rubber) and SN (succinonitrile); The SN in the polymer material acts as a plasticizer. The SN added to the PVDF-HFP disperses the polymer structure and reduces its crystallization. The SN dissociates the lithium salts of the dielectric thin film and promotes ionic conductivity. Lithium salts dispersed in the polymer material lower the energy level of the lithium ions transferred in the polymer material and increase their stability and conductivity. A variety of ceramic composite particles dispersed in the polymer material increase the ionic conductivity and strength of the dielectric thin film, with each of the ceramic composite particles comprising the following: A ceramic particle with high lithium-ion conductivity serves to guide and distribute the lithium ions as they pass through the dielectric thin film. This allows the ceramic particle to form uniformly distributed lithium-ion channels within the dielectric thin film. A dopamine layer surrounds the outer surface of the ceramic particle, thus forming the first particle. The dopamine layer consists of several copolymerized dopamine molecules. A PVDF (polyvinylidene fluoride) layer surrounds the outside of the first particle. wherein the composite ceramic particles are dispersed in the polymer material; the lithium salts added to the polymer material serve to increase the conductivity of the lithium ions and the density of the lithium ions.

Description

AREA OF INVENTION

[0001] The invention relates to a dielectric thin film in a battery and in particular to a single-layer dielectric thin film with ceramic particles which are enclosed in a battery structure of organic material. BACKGROUND OF THE INVENTION

[0002] According to the current state of the art, a solid-state or semi-solid lithium battery consists of a negative (-) electrode, a positive (+) electrode, and a dielectric thin film arranged between them. The negative electrode comprises a negative electrode compound that acts as a binder, in which several negative electrode particles are dispersed. Similarly, the positive electrode consists of a positive electrode compound with positive electrode particles dispersed therein. The dielectric thin film serves as both electrical insulation and the connection between the negative and positive electrodes.

[0003] Current state-of-the-art dielectric thin films utilize ceramic particles. However, these are hygroscopic and form slightly alkaline byproducts when exposed to moisture. These byproducts react with the PVDF-HFP used in the thin film, which can lead to polymer degradation and, in extreme cases, a short circuit in the battery.

[0004] To improve the process, it is proposed to coat the ceramic particles with a hydrophobic dopamine layer to prevent water ingress. However, this dopamine layer does not completely cover the surface of the ceramic particles, leaving areas unprotected. At these exposed areas, the ceramic particles react with the polymer material, impairing the quality and stability of the dielectric thin film. SUMMARY OF THE INVENTION

[0005] In order to overcome the aforementioned shortcomings of the prior art, the invention is based on the objective of providing a single-layer dielectric thin film comprising ceramic particles which are coated with an organic layer.

[0006] In conventional thin films, the ceramic particles form slightly alkaline byproducts which react with the PVDF-HFP used in the thin film and thereby cause its decomposition.

[0007] The invention solves this problem by coating the ceramic particles with a dopamine layer. This coating acts as an additional protective layer, separating the PVDF-HFP matrix from direct contact with the ceramic particles and thus preventing the formation of decomposition reactions. When the ceramic composite particles produced in this way are introduced into the dielectric thin film, they do not react with the polymer material, so that decomposition of the thin film is reliably prevented. BRIEF DESCRIPTION OF THE IMAGES Fig. shows a schematic view illustrating the structure of the invention. Fig. shows a cross-sectional view which shows the structure of the composite ceramic particle according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] With reference to the Fig. The invention relates to a single-layer dielectric thin film 30 comprising ceramic particles coated with organic material and arranged in a battery structure. A solid-state or semi-solid-state lithium battery comprises a negative electrode 10, a positive electrode 20, and the dielectric thin film 30, which is arranged between the negative electrode 10 and the positive electrode 20. As described in Fig. As shown, the negative electrode 10 consists of a negative electrode compound serving as a binder in which several negative electrode particles are dispersed. In a preferred embodiment, these particles are silicon carbide (SiC) coated with a tin (Sn) layer. The outer surface of the negative electrode particles is able to absorb lithium ions and conduct them uniformly into the negative electrode. However, some of the lithium ions react with the negative electrode particles, thereby reducing the number of usable lithium ions. This leads to a reduction in the overall capacity of the lithium battery in the long term.

[0009] The positive electrode 20 comprises a positive electrode mass serving as a binder and several positive electrode particles dispersed therein. The positive electrode mass and the positive electrode particles react with the lithium ions passing through the positive electrode 20, thereby consuming usable lithium ions.

[0010] Referring to Fig. The dielectric thin film 30, connected between the negative electrode 10 and the positive electrode 20, serves both as insulation and as a connection between the negative electrode 10 and the positive electrode 20. The thickness of the dielectric thin film 30 is between 10 µm and 18 µm.

[0011] The dielectric thin film 30 contains the following elements: A polymer material 321 serves as the base material of the dielectric thin film 30. The polymer material 321 consists of a mixture of PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer), HNBR (hydrogenated nitrile butadiene rubber), and SN (succinonitrile). The polymer material 321 also contains PDADMA-TFSI (poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide). In the polymer material 321, the weight ratio of PVDF-HFP, HNBR, and SN is 1:0.0625–0.625:0.125–12.8. The weight ratio of PVDF-HFP, HNBR, and SN is A:B:C, where B is 0.0625 to 0.625 times A and C is 0.125 to 12.8 times A. In this specification, the same uses as defined above have the same meaning.

[0012] The SN in polymer material 321 acts as a plasticizer. The SN added to the PVDF-HFP disperses the structure of the polymer material 321 and reduces its crystallization. The SN serves to dissociate lithium salts (i.e., lithium salts 322, as described below) of the dielectric thin film 30 and promotes the conductivity of the ions.

[0013] The lithium salts 322 are dispersed in the polymer material 321. These lithium salts 322 consist of a mixture of LiFSI (F₂LiNO₄S₂, lithium bis(fluorosulfonyl)imide), LiTSFI (LiN(CF₃SO₂)₂, lithium bis(trifluoromethanesulfonyl)imide), and LiCl. In the dielectric thin film 30, the weight ratio of LiFSI, LiTSFI, and LiCl is 1:2:0.1. The lithium salts 322 serve to lower the energy level of the lithium ions transferred in the polymer material. Furthermore, the lithium salts 322 also increase the stability and conductivity of the lithium ions in the polymer material 321. The weight ratio of the lithium salts 322 to the polymer material 321 ranges from 1:3 to 9.

[0014] Several ceramic composite particles 100 are dispersed in polymer material 321. The ceramic composite particles 100 serve to increase the ionic conductivity and the strength of the dielectric thin film 30. The weight fraction of the ceramic composite particles 100 in polymer material 321 is between eight and 20 wt.%.

[0015] Referring to the Fig. Each of the ceramic composite particles comprises 100 of the following elements: A ceramic particle 32 with high lithium-ion conductivity serves to guide and distribute the lithium ions as they pass through the dielectric thin film 30. This allows the ceramic particle 32 to form uniformly distributed lithium-ion channels in the dielectric thin film 30. The particle size of the ceramic particle 32 is less than 100 nm. A dopamine layer 34 surrounds the outer surface of the ceramic particle 32, forming a first particle 35. The dopamine layer 34 consists of a multitude of copolymerized dopamine molecules. The thickness of the dopamine layer 34 is between 2 nm and 15 nm. The method of combining the copolymerized dopamine molecules with the ceramic particle 32 is known in the prior art; therefore, the details of the combination are not described here. A PVDF (polyvinylidene fluoride) layer 36 encloses the outer surface of the first particle 35. The thickness of the PVDF layer 36 is between 10 nm and 100 nm. The size of the ceramic composite particle 100 is less than 300 nm.

[0016] The ceramic particle 32 consists of at least one of the following materials: ceramic oxides, oxides with a garnet structure, and oxides with a perovskite structure. The lithium ion conductivity of the ceramic oxides is greater than 10 -5 cm 2 / s (diffusion coefficient).

[0017] The ceramic oxides are LAGP (lithium aluminum germanium phosphate) with a NASICON structure (sodium (Na) superion conductor). The oxides with a garnet structure can be LLZO (Li7La3Zr2O). 12 The ceramic particle 32 can be formed by combining the above-mentioned materials in any desired ratio. These materials can be lithium lanthanum zirconium oxide or the perovskite-structured oxides LLTO (lithium lanthanum titanium oxide).

[0018] The ceramic particle 32 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) and Al-LLZO (aluminium-doped LLZO).

[0019] If the ceramic particles 32 consist of LAGPs, the LAGPs are 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.

[0020] In the dielectric thin film 30, the polymer material 321 serves to disperse and support the material within the dielectric thin film 30. The ceramic particles 100 added to the dielectric thin film 30 rapidly conduct the lithium ions, thus achieving high conductivity. As the lithium ions pass through the dielectric thin film 30, the ceramic particles 32, with their high lithium-ion conductivity, facilitate the passage of the lithium ions through the dielectric thin film 30 and distribute lithium ion channels within it. The ceramic particles 32 prevent side reactions between the lithium ions and the dielectric thin film 30. Furthermore, the lithium salts 322 added to the polymer material 321 increase the conductivity and density of the lithium ions.

[0021] The invention thus relates to a single-layer dielectric thin film in a battery structure, wherein the battery structure comprises a negative electrode, a positive electrode and a dielectric thin film arranged between the negative and the positive electrode, characterized in that the dielectric thin film contains a polymer material as a base material, lithium salts dispersed therein and several ceramic composite particles dispersed therein, each ceramic composite particle consisting of a ceramic particle, a dopamine layer surrounding the ceramic particle and a PVDF (polyvinylidene fluoride) layer enclosing the dopamine layer.

[0022] In describing the 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 protection of the following claims.

Claims

[1] A single-layer dielectric thin film with ceramic particles embedded in organic material in a battery structure; wherein a solid or semi-solid lithium battery comprises a negative electrode, a positive electrode and the dielectric thin film layer connected between the negative electrode and the positive electrode; A dielectric thin film comprising: A polymer material as a base material for the dielectric thin film consisting of a mixture of PVDF-HFP (polyvinylidene fluoride hexafluoropropylene copolymer), HNBR (hydrogenated nitrile butadiene rubber) and SN (succinonitrile); The SN in the polymer material acts as a plasticizer. The SN added to the PVDF-HFP disperses the polymer structure and reduces its crystallization. The SN dissociates the lithium salts of the dielectric thin film and promotes ionic conductivity. Lithium salts dispersed in the polymer material lower the energy level of the lithium ions transferred in the polymer material and increase their stability and conductivity. A variety of ceramic composite particles dispersed in the polymer material increase the ionic conductivity and strength of the dielectric thin film, with each of the ceramic composite particles comprising the following: A ceramic particle with high lithium-ion conductivity serves to guide and distribute the lithium ions as they pass through the dielectric thin film. This allows the ceramic particle to form uniformly distributed lithium-ion channels within the dielectric thin film. A dopamine layer surrounds the outer surface of the ceramic particle, thus forming the first particle. The dopamine layer consists of several copolymerized dopamine molecules. A PVDF (polyvinylidene fluoride) layer surrounds the outside of the first particle. wherein the composite ceramic particles are dispersed in the polymer material; the lithium salts added to the polymer material serve to increase the conductivity of the lithium ions and the density of the lithium ions. [2] Single-layer dielectric thin film according to claim 1, characterized by that the ceramic particles consist of at least one of the following materials: ceramic oxides, garnet-structured oxides, or perovskite-structured oxides, wherein the lithium ion conductivity of the ceramic oxides is higher than 10 -5 cm 2 / s (diffusion coefficient) is. [3] Single-layer dielectric thin film according to claim 2, characterized by that the ceramic oxides are LAGP (lithium aluminum germanium phosphate) with a NASICON structure (sodium superion conductor). [4] Single-layer dielectric thin film according to claim 2, characterized by that the oxides with garnet structure LLZO (Li7La3Zr2O 12, lithium lanthanum zirconium oxide) or the oxides with perovskite structure LLTO (lithium lanthanum titanium oxide). [5] Single-layer dielectric thin film according to claim 1, characterized by that the ceramic particles 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). [6] Single-layer dielectric thin film according to claim 1, wherein the ceramic particles are formed from LAGPs and selected from 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, where 0.1≤x≤0.8, 0≤y≤0.2, 0≤z≤0.2, M is a trivalent cation and N is a tetravalent cation. [7] Single-layer dielectric thin film according to claim 6, wherein the trivalent cation is selected from scandium cation (Sc3+ ), Yttrium cation (Y 3+ ), Gallium cation (Ga 3+ ), Indium cation (In 3+ ) and lanthanum cation (La 3+ ); The tetravalent cation is formed from the zirconium cation (Zr 4+ ), silicon cation (Si 4+ ) and tin cation (Sn 4+ ) selected. [8] Single-layer dielectric thin film according to claim 1, wherein the thickness of the dielectric thin film is between 10 µm and 18 µm. [9] Single-layer dielectric thin film according to claim 1, wherein the weight ratio of PVDF-HFP, HNBR and SN in the polymer material is 1:0.0625-0.625:0.125-12.

8. [10] Single-layer dielectric thin film according to claim 1, wherein the polymer material additionally contains PDADMA-TFSI (poly(diallyldimethylammonium)-bis(trifluoromethanesulfonyl)imide). [11] Single-layer dielectric thin film according to claim 1, characterized by, that the lithium salts are a mixture of LiFSI (lithium bis(fluorosulfonyl)imide, F2LiNO4S2), LiTSFI (lithium bis(trifluoromethanesulfonyl)imide, LiN(CF3SO2)2) and LiCl, wherein the weight ratio of LiFSI:LiTSFI:LiCl in the dielectric thin film is 1:2:0.

1. [12] Single-layer dielectric thin film according to claim 1, characterized by , that the weight ratio of lithium salts to polymer material is in the range of 1:3 to 1:

9. [13] Single-layer dielectric thin film according to claim 1, characterized by that the weight fraction of the composite ceramic particles in the polymer material is between eight wt.% and 20 wt.%. [14] Single-layer dielectric thin film according to claim 1, characterized by , that the size of the ceramic particles is less than 100 nm, the size of the composite ceramic particles is less than 300 nm, the thickness of the PVDF layer is between 10 nm and 100 nm, and the thickness of the dopamine layer is between 2 nm and 15 nm.

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