Indium-containing negative electrode, and electrochemical device and electronic device comprising same

Abstract

The invention discloses an indium-containing negative electrode and an electrochemical device and an electronic device comprising the same, the indium-containing negative electrode comprises a negative electrode current collector, a negative electrode active material layer, a metal lithium layer and a metal indium layer, the negative electrode active material layer is located between the negative electrode current collector and the metal lithium layer, the metal lithium layer is located between the negative electrode active material layer and the metal indium layer, the negative electrode active material layer comprises indium powder, based on the mass of the negative electrode active material layer, the mass ratio of the indium powder is w%, the surface density of the metal indium layer is p mg / cm < 2 >, and w * p is larger than or equal to 5 and smaller than or equal to 50. According to the indium-containing negative electrode, the electronic conductivity of the negative electrode and the cycle capacity retention ratio of a sulfide all-solid-state battery can be improved, and the volume expansion rate of the negative electrode can be reduced.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more specifically, to indium-containing anodes and electrochemical and electronic devices containing them. Background Technology

[0002] All-Solid-State Batteries (ASSBs), one of the electrochemical devices, are considered the ultimate direction for next-generation energy storage technology due to their high safety and theoretical energy density. However, the commercialization of ASSBs faces two major challenges: first, the severe interfacial side reactions and lithium dendrite growth between the highly active lithium metal anode and the sulfide solid electrolyte [such as the lithium-sulfur-phosphorus-chloride fast ion conductor (Li6PS5Cl)]; and second, the low intrinsic electronic / ionic conductivity, severe volume expansion during cycling, and unstable interfacial contact with the solid electrolyte present in high-capacity silicon anodes. These problems lead to low electronic conductivity and high volume expansion rate of the anode, as well as low cycle capacity retention of ASSBs.

[0003] Therefore, developing new indium-containing anodes to improve the electronic conductivity of the anode, the cycle capacity retention of sulfide all-solid-state batteries, and reduce the volume expansion rate of the anode is of great significance. Summary of the Invention

[0004] The purpose of this application is to address the problems of low electronic conductivity of the negative electrode in sulfide all-solid-state batteries, as well as low cycle capacity retention and high volume expansion rate of sulfide all-solid-state batteries, and to provide an indium-containing negative electrode and an electrochemical device and electronic device containing therein.

[0005] To achieve the above objectives, this application provides an indium-containing anode, comprising an anode current collector, an anode active material layer, a lithium metal layer, and an indium metal layer. The anode active material layer is located between the anode current collector and the lithium metal layer, and the lithium metal layer is located between the anode active material layer and the indium metal layer. The anode active material layer comprises indium powder, and based on the mass of the anode active material layer, the mass percentage of indium powder is w%, and the areal density of the indium metal layer is p mg / cm³. 2 , 5≤w×p≤50.

[0006] The indium-containing anode of this application controls the mass percentage of indium powder (w%) and the areal density of the metallic indium layer (p mg / cm³). 2 Satisfying the formula "5≤w×p≤50" can improve the electronic conductivity of the negative electrode and the cycle capacity retention rate of sulfide all-solid-state batteries, as well as reduce the volume expansion rate of the negative electrode.

[0007] Specifically, in the negative electrode active material layer, indium powder undergoes an alloying reaction with lithium ions during the initial cycling phase of the electrochemical device to form a LiIn alloy with high electronic conductivity. The Li / In alloy interface layer formed by the lithium metal layer and the indium metal layer is a macroscopic, dense, and highly conductive layer, providing the main channel for current collection and lithium ion interfacial exchange. The indium metal layer is the direct contact site for current collection and lithium ion interfacial exchange. When the mass percentage of indium powder (w%) and the areal density of the indium metal layer (p mg / cm³) are... 2 When the formula "5≤w×p≤50" is satisfied, the LiIn alloy particles in the negative electrode active material layer will form a stable rigid network structure between the negative electrode active material (such as silicon active material) particles, which can promote the transport of electrons and ions. It works together with the Li / In alloy interface layer formed by the indium metal layer to form a continuous and seamless mixed conductive network from the inside (negative electrode active material layer) to the outside (Li / In alloy interface layer) of the indium-containing negative electrode, which can effectively improve the electronic conductivity of the negative electrode. At the same time, the rigid network structure formed by the LiIn alloy particles and the continuous and seamless mixed conductive network composed of the Li / In alloy interface layer can also effectively stabilize the interface between the indium-containing negative electrode and the sulfide solid electrolyte, suppress the interfacial side reactions between the indium-containing negative electrode and the sulfide solid electrolyte, and stably and quickly transfer lithium ions from the outside (Li / In alloy interface layer) to the inside (negative electrode active material layer) of the indium-containing negative electrode, thereby helping to reduce the volume expansion rate of the negative electrode and improve the cycle capacity retention rate of the sulfide all-solid-state battery.

[0008] In some implementations, 12 ≤ w × p ≤ 36.

[0009] In some implementations, 2.0 ≤ w ≤ 15.0.

[0010] In some implementations, 1.0 ≤ p ≤ 4.0.

[0011] In some embodiments, the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (0.5-4):1.

[0012] In some embodiments, the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (1.2-3):1.

[0013] When the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer satisfies Li:In=(1.2-3):1, it is beneficial to further improve the electronic conductivity of the negative electrode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as to further reduce the volume expansion rate of the negative electrode.

[0014] Specifically, in this application, the Li / In alloy interface layer composed of the lithium metal layer and the indium metal layer contains multiple thermodynamically stable intermetallic compound phases, such as the LiIn phase and the Li3In phase. These two phases can create a broad and flat voltage plateau in the range of 0.55-0.70V for the indium-containing anode. Since the working potential of this voltage plateau is much higher than the deposition potential of lithium metal (0V), the precipitation of lithium dendrites is completely avoided thermodynamically. Moreover, the working potential of this voltage plateau forms a safe "buffer band" between the lithium metal (0V) and the lower limit of the stability window of the sulfide solid electrolyte (approximately 0.7-1.0V), effectively preventing the sulfide solid electrolyte from being reduced and decomposed due to excessively low anode potential. This further improves the interfacial stability between the indium-containing anode and the sulfide solid electrolyte, thereby helping to further reduce the volume expansion rate of the anode and improve the cycle capacity retention rate of the sulfide all-solid-state battery. When the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (1.2-3):1, the Li / In alloy interface layer will be completely or mainly in the thermodynamically stable region where the LiIn phase and Li3In phase coexist. This will further help to reduce the volume expansion rate of the negative electrode and improve the cycle capacity retention rate of the sulfide all-solid-state battery. At the same time, it can also improve the conductivity of the hybrid conductive network (composed of LiIn alloy particles in the negative electrode active material layer and the Li / In alloy interface layer) as mentioned above, thereby further improving the electronic conductivity of the negative electrode.

[0015] In some embodiments, the voltage plateau is 0.55-0.70V when the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In=(1.2-3):1.

[0016] In some embodiments, the thickness of the indium layer is 1-15 μm.

[0017] In some implementations, the lithium metal layer is made of elemental lithium.

[0018] In some implementations, the indium layer is made of elemental indium.

[0019] In some implementations, the indium powder is made of elemental indium.

[0020] In some embodiments, the average particle size of the indium powder is 200-800 mesh.

[0021] In some embodiments, the negative electrode active material layer further includes at least one of the following: negative electrode active material, negative electrode conductive agent, and negative electrode binder.

[0022] In some embodiments, the negative electrode active material includes a silicon active material.

[0023] In some embodiments, the silicon-active material includes at least one of Si materials, silicon-carbon (Si-C) composite materials, and silicon-oxygen (Si-O) composite materials.

[0024] In some embodiments, the Si material is elemental silicon and / or a silicon-based alloy.

[0025] In some embodiments, the Si material is silicon powder and / or silicon ingot.

[0026] In some embodiments, the silicon-carbon (Si-C) composite material is a material containing both Si and C elements.

[0027] In some embodiments, the silicon-carbon (Si-C) composite material is SiC.

[0028] In some embodiments, the silicon-oxygen (Si-O) composite material is a material containing Si and O elements.

[0029] In some embodiments, the silicon-oxygen (Si-O) composite material is SiO2. x x = 1.0 - 2.0.

[0030] In some embodiments, the average particle size Dv50 of the silicon active material is 300-2500 nm.

[0031] This application also provides an electrochemical device comprising any of the indium-containing negative electrode, positive electrode, and electrolyte described herein, wherein the positive electrode comprises a positive electrode active material.

[0032] In some embodiments, the mass of indium per unit area in the indium-containing anode is a mg / cm³. 2 The mass of the positive electrode active material per unit area in the positive electrode is b mg / cm³. 2 , 0.03≤a / b≤0.50.

[0033] In some implementations, 0.05 ≤ a / b ≤ 0.30.

[0034] In this application, when the mass of indium per unit area in the indium-containing negative electrode is a mg / cm³ 2 The mass of positive electrode active material per unit area in the positive electrode, b mg / cm³ 2 When the condition “0.05≤a / b≤0.30” is met, the indium powder and metallic indium layer in the electrochemical device can play their respective roles more fully, thereby further improving the electronic conductivity of the negative electrode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as further reducing the volume expansion rate of the negative electrode.

[0035] In this application, the indium element in "mass of indium element per unit area in indium-containing anode" includes the indium element in the metallic indium layer and the indium element in the indium powder in the anode active material layer.

[0036] In some implementations, 0.12 ≤ a / b ≤ 0.20.

[0037] In some implementations, 1.0 ≤ a ≤ 5.0.

[0038] In some implementations, 10.0 ≤ b ≤ 30.0.

[0039] In some implementations, the positive electrode also includes a sulfide solid electrolyte.

[0040] In some embodiments, the electrolyte includes a sulfide solid electrolyte.

[0041] In some embodiments, the sulfide solid electrolyte includes Li6PS5Cl, Li6PS5Br, and Li 10 GeP2S 12 Li 10 SnP2S 12 Li4SiS4, Li7P3S 11 Li6PS5I, Li 10 SiP2S 12 At least one of them.

[0042] In some implementations, the electrochemical device can be a sulfide all-solid-state battery.

[0043] This application also provides an electronic device that includes the electrochemical device described above.

[0044] Compared with the prior art, the beneficial effects of this application are as follows: The indium-containing anode of this application controls the mass percentage of indium powder (w%) and the areal density of the metallic indium layer (p mg / cm³). 2 Satisfying the formula "5≤w×p≤50" can improve the electronic conductivity of the negative electrode and the cycle capacity retention rate of sulfide all-solid-state batteries, as well as reduce the volume expansion rate of the negative electrode.

[0045] Specifically, in the negative electrode active material layer, indium powder undergoes an alloying reaction with lithium ions during the initial cycling phase of the electrochemical device to form a LiIn alloy with high electronic conductivity. The Li / In alloy interface layer formed by the lithium metal layer and the indium metal layer is a macroscopic, dense, and highly conductive layer, providing the main channel for current collection and lithium ion interfacial exchange. The indium metal layer is the direct contact site for current collection and lithium ion interfacial exchange. When the mass percentage of indium powder (w%) and the areal density of the indium metal layer (p mg / cm³) are... 2When the formula "5≤w×p≤50" is satisfied, the LiIn alloy particles in the negative electrode active material layer will form a stable rigid network structure between the negative electrode active material (such as silicon active material) particles, which can promote the transport of electrons and ions. It works together with the Li / In alloy interface layer formed by the indium metal layer to form a continuous and seamless mixed conductive network from the inside (negative electrode active material layer) to the outside (Li / In alloy interface layer) of the indium-containing negative electrode, which can effectively improve the electronic conductivity of the negative electrode. At the same time, the rigid network structure formed by the LiIn alloy particles and the continuous and seamless mixed conductive network composed of the Li / In alloy interface layer can also effectively stabilize the interface between the indium-containing negative electrode and the sulfide solid electrolyte, suppress the interfacial side reactions between the indium-containing negative electrode and the sulfide solid electrolyte, and stably and quickly transfer lithium ions from the outside (Li / In alloy interface layer) to the inside (negative electrode active material layer) of the indium-containing negative electrode, thereby helping to reduce the volume expansion rate of the negative electrode and improve the cycle capacity retention rate of the sulfide all-solid-state battery.

[0046] When the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer satisfies Li:In=(1.2-3):1, it is beneficial to further improve the electronic conductivity of the negative electrode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as to further reduce the volume expansion rate of the negative electrode.

[0047] Specifically, in this application, the Li / In alloy interface layer composed of the lithium metal layer and the indium metal layer contains multiple thermodynamically stable intermetallic compound phases, such as the LiIn phase and the Li3In phase. These two phases can create a broad and flat voltage plateau in the range of 0.55-0.70V for the indium-containing anode. Since the working potential of this voltage plateau is much higher than the deposition potential of lithium metal (0V), the precipitation of lithium dendrites is completely avoided thermodynamically. Moreover, the working potential of this voltage plateau forms a safe "buffer band" between the lithium metal (0V) and the lower limit of the stability window of the sulfide solid electrolyte (approximately 0.7-1.0V), effectively preventing the sulfide solid electrolyte from being reduced and decomposed due to excessively low anode potential. This further improves the interfacial stability between the indium-containing anode and the sulfide solid electrolyte, thereby helping to further reduce the volume expansion rate of the anode and improve the cycle capacity retention rate of the sulfide all-solid-state battery. When the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (1.2-3):1, the Li / In alloy interface layer will be completely or mainly in the thermodynamically stable region where the LiIn phase and Li3In phase coexist. This will further help to reduce the volume expansion rate of the negative electrode and improve the cycle capacity retention rate of the sulfide all-solid-state battery. At the same time, it can also improve the conductivity of the hybrid conductive network (composed of LiIn alloy particles in the negative electrode active material layer and the Li / In alloy interface layer) as mentioned above, thereby further improving the electronic conductivity of the negative electrode.

[0048] In this application, when the mass of indium per unit area in the indium-containing negative electrode is a mg / cm³ 2 The mass of positive electrode active material per unit area in the positive electrode, b mg / cm³ 2 When the condition “0.05≤a / b≤0.30” is met, the indium powder and metallic indium layer in the electrochemical device can play their respective roles more fully, thereby further improving the electronic conductivity of the negative electrode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as further reducing the volume expansion rate of the negative electrode. Attached Figure Description

[0049] Figure 1 The diagram shows the specific capacity and voltage relationship of the indium-containing negative electrode in Example 9 during the discharge process. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] <General Definition> The term "area density of indium layer" refers to the mass of indium per unit area in an indium layer.

[0052] The term "average particle size Dv50" refers to the particle size value that corresponds to a cumulative volume percentage of 50% in a particle group.

[0053] The embodiments of this application may omit unnecessary detailed descriptions. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0054] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0055] In this application, a list of items connected by the term "at least one of" can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another instance, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.

[0056] In the following description, all figures disclosed in this application are approximate values, regardless of whether the terms "about" or "approximately" are used in conjunction. They may vary by 1%, 2%, 5%, or sometimes 10% to 20%. Whenever a range of values ​​with a lower limit (RL) and an upper limit (RU) is disclosed, any values ​​falling within that range are specifically disclosed. Specifically, the following values ​​within this range are specifically disclosed: R = RL + k * (RU - RL), where k is a variable with a 1% increment from 1% to 100%, i.e., k is 1%, 2%, 3%, 4%, 5%, ..., 50%, 51%, 52%, ..., 95%, 96%, 97%, 98%, 99%, or 100%. Furthermore, any range of values ​​defined by the two R values ​​as defined above are also specifically disclosed.

[0057] In this application, numerical ranges are involved. Unless otherwise specified, the numerical ranges mentioned above are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form a range not explicitly stated.

[0058] Throughout this specification, references to "implementation," "partial implementation," "one implementation," "some implementations," "another implementation," "specific implementation," or "partial implementation" mean that at least one implementation or embodiment in this application includes the specific features, structures, materials, or characteristics described in that implementation or embodiment.

[0059] I. Indium-containing anode This application provides an indium-containing anode, comprising an anode current collector, an anode active material layer, a lithium metal layer, and an indium metal layer. The anode active material layer is located between the anode current collector and the lithium metal layer, and the lithium metal layer is located between the anode active material layer and the indium metal layer. The anode active material layer includes indium powder, and based on the mass of the anode active material layer, the indium powder accounts for w% of the total mass. The areal density of the indium metal layer is p mg / cm³. 2 , 5≤w×p≤50.

[0060] The indium-containing anode of this application controls the mass percentage of indium powder (w%) and the areal density of the metallic indium layer (p mg / cm³). 2 Satisfying the formula "5≤w×p≤50" can improve the electronic conductivity of the negative electrode and the cycle capacity retention rate of sulfide all-solid-state batteries, as well as reduce the volume expansion rate of the negative electrode.

[0061] Specifically, in the negative electrode active material layer, indium powder undergoes an alloying reaction with lithium ions during the initial cycling phase of the electrochemical device to form a LiIn alloy with high electronic conductivity. The Li / In alloy interface layer formed by the lithium metal layer and the indium metal layer is a macroscopic, dense, and highly conductive layer, providing the main channel for current collection and lithium ion interfacial exchange. The indium metal layer is the direct contact site for current collection and lithium ion interfacial exchange. When the mass percentage of indium powder (w%) and the areal density of the indium metal layer (p mg / cm³) are... 2When the formula "5≤w×p≤50" is satisfied, the LiIn alloy particles in the negative electrode active material layer will form a stable rigid network structure between the negative electrode active material (such as silicon active material) particles, which can promote the transport of electrons and ions. It works together with the Li / In alloy interface layer formed by the indium metal layer to form a continuous and seamless mixed conductive network from the inside (negative electrode active material layer) to the outside (Li / In alloy interface layer) of the indium-containing negative electrode, which can effectively improve the electronic conductivity of the negative electrode. At the same time, the rigid network structure formed by the LiIn alloy particles and the continuous and seamless mixed conductive network composed of the Li / In alloy interface layer can also effectively stabilize the interface between the indium-containing negative electrode and the sulfide solid electrolyte, suppress the interfacial side reactions between the indium-containing negative electrode and the sulfide solid electrolyte, and stably and quickly transfer lithium ions from the outside (Li / In alloy interface layer) to the inside (negative electrode active material layer) of the indium-containing negative electrode, thereby helping to reduce the volume expansion rate of the negative electrode and improve the cycle capacity retention rate of the sulfide all-solid-state battery.

[0062] In some implementations, w×p can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50, or fall within the range of any two of the above values.

[0063] In some implementations, 12 ≤ w × p ≤ 36.

[0064] In some implementations, 2.0 ≤ w ≤ 15.0. For example, w can be 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, or 15.0, or fall within the range of any two of the above values.

[0065] In some implementations, 1.0 ≤ p ≤ 4.0. For example, p can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0, or fall within the range of any two of the above values.

[0066] In some embodiments, the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (0.5-4):1. For example, the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, or 4:1, or fall within the range of any two of the above values.

[0067] In some embodiments, the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (1.2-3):1.

[0068] When the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer satisfies Li:In=(1.2-3):1, it is beneficial to further improve the electronic conductivity of the negative electrode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as to further reduce the volume expansion rate of the negative electrode.

[0069] Specifically, in this application, the Li / In alloy interface layer composed of the lithium metal layer and the indium metal layer contains multiple thermodynamically stable intermetallic compound phases, such as the LiIn phase and the Li3In phase. These two phases can create a broad and flat voltage plateau in the range of 0.55-0.70V for the indium-containing anode. Since the working potential of this voltage plateau is much higher than the deposition potential of lithium metal (0V), the precipitation of lithium dendrites is completely avoided thermodynamically. Moreover, the working potential of this voltage plateau forms a safe "buffer band" between the lithium metal (0V) and the lower limit of the stability window of the sulfide solid electrolyte (approximately 0.7-1.0V), effectively preventing the sulfide solid electrolyte from being reduced and decomposed due to excessively low anode potential. This further improves the interfacial stability between the indium-containing anode and the sulfide solid electrolyte, thereby helping to further reduce the volume expansion rate of the anode and improve the cycle capacity retention rate of the sulfide all-solid-state battery. When the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In = (1.2-3):1, the Li / In alloy interface layer will be completely or mainly in the thermodynamically stable region where the LiIn phase and Li3In phase coexist. This will further help to reduce the volume expansion rate of the negative electrode and improve the cycle capacity retention rate of the sulfide all-solid-state battery. At the same time, it can also improve the conductivity of the hybrid conductive network (composed of LiIn alloy particles in the negative electrode active material layer and the Li / In alloy interface layer) as mentioned above, thereby further improving the electronic conductivity of the negative electrode.

[0070] In some embodiments, the voltage plateau under the condition that the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In=(1.2-3):1 is 0.55-0.70V. Exemplarily, the voltage plateau under the condition that the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In=(1.2-3):1 can be 0.55V, 0.56V, 0.57V, 0.58V, 0.59V, 0.60V, 0.61V, 0.62V, 0.63V, 0.64V, 0.65V, 0.66V, 0.67V, 0.68V, 0.69V, or 0.70V, or falls within the range of any two of the above values.

[0071] In some embodiments, the thickness of the indium layer is 1-15 μm. Exemplarily, the thickness of the indium layer can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, or 15 μm, or within a range of any two of the above values.

[0072] In some implementations, the lithium metal layer is made of elemental lithium.

[0073] In some implementations, the indium layer is made of elemental indium.

[0074] In some implementations, the indium powder is made of elemental indium.

[0075] In some embodiments, the average particle size of the indium powder is 200-800 mesh. Exemplarily, it is 200 mesh, 250 mesh, 300 mesh, 325 mesh, 350 mesh, 400 mesh, 450 mesh, 500 mesh, 550 mesh, 600 mesh, 650 mesh, 700 mesh, 750 mesh, or 800 mesh, or within the range of any two of the above values.

[0076] In some embodiments, the negative electrode active material layer further includes at least one of the following: negative electrode active material, negative electrode conductive agent, and negative electrode binder.

[0077] In some embodiments, the negative electrode active material includes a silicon active material.

[0078] In some embodiments, the silicon-active material includes at least one of Si materials, silicon-carbon (Si-C) composite materials, and silicon-oxygen (Si-O) composite materials.

[0079] In some embodiments, the Si material is elemental silicon and / or a silicon-based alloy.

[0080] In some embodiments, the Si material is silicon powder and / or silicon ingot.

[0081] In some embodiments, the silicon-carbon (Si-C) composite material is a material containing both Si and C elements.

[0082] In some embodiments, the silicon-carbon (Si-C) composite material is SiC.

[0083] In some embodiments, the silicon-oxygen (Si-O) composite material is a material containing Si and O elements.

[0084] In some embodiments, the silicon-oxygen (Si-O) composite material is SiO2. x x = 1.0 - 2.0.

[0085] In some embodiments, the average particle size Dv50 of the silicon active material is 300-2500 nm. For example, the average particle size Dv50 of the silicon active material can be 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 11200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, or 2000 nm, or fall within the range of any two of the above values.

[0086] In some embodiments, the mass percentage of the negative electrode active material is 55%-95% based on the mass of the negative electrode active material layer. For example, the mass percentage of the negative electrode active material can be 55%, 58%, 60%, 62%, 63%, 64%, 65%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%, or fall within the range of any two of the aforementioned values.

[0087] In some implementations, the mass percentage of the negative electrode active material is 70%-95%, based on the mass of the negative electrode active material layer.

[0088] In some embodiments, the negative electrode conductive agent includes at least one of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, superconducting carbon, acetylene black, Ketjen black, carbon dots, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, activated carbon, and mesoporous carbon. The negative electrode conductive agent of this application is not limited to the above materials, but also includes other materials that can be used as battery negative electrode conductive agents.

[0089] In some embodiments, other negative electrode binders may include at least one of polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyacrylamide, styrene-butadiene rubber, acrylic styrene-butadiene rubber, acrylic acid-acrylonitrile-acrylamide copolymer, acrylic acid-acrylonitrile-acrylate copolymer, acrylonitrile-butadiene rubber, nitrile rubber, acrylonitrile-styrene-butadiene copolymer, acryloyl rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyvinyl alcohol, polyvinyl acetate, polyepoxychloropropane, polyphosphazene, polyacrylonitrile, polystyrene, latex, acrylic resin, phenolic resin, epoxy resin, carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl cellulose, carboxymethyl chitosan, polyester, polyamide, polyether, polyimide, polycarboxylic acid ester, polycarboxylic acid, polyurethane, alginate, fluorinated polymer, chlorinated polymer, polyvinylidene fluoride, and poly(vinylidene fluoride)-hexafluoropropylene. Other negative electrode binders in this application are not limited to the materials described above, but also include other materials that can be used as battery negative electrode binders.

[0090] In some embodiments, the negative electrode current collector is a metal foil or a composite current collector. In some embodiments, the metal foil is a copper foil. The composite current collector may include a metal foil substrate and a conductive layer disposed on at least one side of the metal foil substrate. In some embodiments, the conductive layer may include at least one of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, activated carbon, and mesoporous carbon.

[0091] II. Electrochemical Device This application also provides an electrochemical device comprising any of the indium-containing negative electrode, positive electrode, and electrolyte described herein, wherein the positive electrode comprises a positive electrode active material.

[0092] In this application, the electrochemical device includes any device in which an electrochemical reaction occurs to interconvert chemical energy and electrical energy. In some embodiments, the electrochemical device may be a sulfide all-solid-state battery.

[0093] In some embodiments, the mass of indium per unit area in the indium-containing anode is a mg / cm³. 2 The mass of the positive electrode active material per unit area in the positive electrode is b mg / cm³. 2 , 0.03≤a / b≤0.50.

[0094] In some implementations, 0.05 ≤ a / b ≤ 0.30.

[0095] In this application, when the mass of indium per unit area in the indium-containing negative electrode is a mg / cm³ 2 The mass of positive electrode active material per unit area in the positive electrode, b mg / cm³2 When the condition “0.05≤a / b≤0.30” is met, the indium powder and metallic indium layer in the electrochemical device can play their respective roles more fully, thereby further improving the electronic conductivity of the negative electrode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as further reducing the volume expansion rate of the negative electrode.

[0096] In some implementations, a / b can be 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.32, 0.33, 0.35, 0.37, 0.38, 0.40, 0.42, 0.43, 0.45, 0.47, 0.48, or 0.50, or fall within the range of any two of the above values.

[0097] In this application, the indium element in "mass of indium element per unit area in indium-containing anode" includes the indium element in the metallic indium layer and the indium element in the indium powder in the anode active material layer.

[0098] In some implementations, 0.12 ≤ a / b ≤ 0.20.

[0099] In some implementations, 1.0 ≤ a ≤ 5.0. For example, a can be 1.0, 1.2, 1.3, 1.5, 1.7, 1.8, 2, 2.2, 2.3, 2.5, 2.7, 2.8, 3, 3.2, 3.3, 3.5, 3.7, 3.8, 4, 4.2, 4.3, 4.5, 4.7, 4.8 or 5, or fall within the range of any two of the above values.

[0100] In some implementations, 10.0 ≤ b ≤ 30.0. For example, b can be 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0, or 30.0, or fall within the range of any two of the above values.

[0101] 1. Positive electrode In some embodiments, the positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector.

[0102] In some embodiments, the positive current collector is a metal foil or a composite current collector. In some embodiments, the metal foil is aluminum foil. The composite current collector may include a metal foil substrate and a conductive layer disposed on at least one side of the metal foil substrate. In some embodiments, the conductive layer may include at least one of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, activated carbon, and mesoporous carbon.

[0103] In some embodiments, the positive electrode active material layer may include at least one of the following: positive electrode active material, positive electrode binder, positive electrode conductive agent, and sulfide solid electrolyte.

[0104] In some embodiments, the positive electrode active material is selected from LiCoO2, LiNiO2, and LiNi x Mn y O2, Li 1+ z Ni x Mn y Co 1-x-y O2, LiNi x Co y Al z The group consisting of O2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, Li2MnO3, LiFeO2, LiFePO4, LiMnPO4, and combinations thereof, wherein each x is independently 0.2 to 0.9; each y is independently 0.1 to 0.45; and each z is independently 0 to 0.2. The positive electrode active material of this application is not limited to the above-mentioned materials, but also includes other materials that can be used as positive electrode active materials.

[0105] In some embodiments, the positive electrode binder includes at least one of polyvinylidene fluoride (PVDF), poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), polytetrafluoroethylene (PTFE), polyisobutylene (PIB), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyacrylic acid, polyacrylonitrile, polyimide, polyurethane, polyvinyl butyral, polyvinylpyrrolidone (PVP), acrylic acid-acrylonitrile-acrylamide copolymer, and acrylic acid-acrylonitrile-acrylate copolymer. The positive electrode binder of this application is not limited to the above materials, but also includes other materials that can be used as battery positive electrode binders.

[0106] In some embodiments, the positive electrode conductive agent may include at least one of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, superconducting carbon, acetylene black, conductive carbon black, Ketjen black, carbon dots, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, activated carbon, and mesoporous carbon. The positive electrode conductive agent in this application is not limited to the above materials, but also includes other materials that can be used as positive electrode conductive agents in batteries.

[0107] In some embodiments, the sulfide solid electrolyte includes Li6PS5Cl, Li6PS5Br, and Li 10 GeP2S 12 Li 10 SnP2S 12 Li4SiS4, Li7P3S 11 Li6PS5I, Li 10 SiP2S 12 At least one of them.

[0108] 2. Electrolytes In some embodiments, the electrolyte includes a sulfide solid electrolyte.

[0109] In some embodiments, the sulfide solid electrolyte includes Li6PS5Cl, Li6PS5Br, and Li 10 GeP2S 12 Li 10 SnP2S 12 Li4SiS4, Li7P3S 11 Li6PS5I, Li 10 SiP2S 12 At least one of them.

[0110] III. Electronic devices This application also provides an electronic device that includes the electrochemical device described above.

[0111] The electronic device described in this application is not particularly limited and can be any electronic device known in the prior art. The electrochemical device described in this application is also not particularly limited in its use and can be used in any electronic device known in the prior art. According to some embodiments of this application, the electronic device includes, but is not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, and android robots.

[0112] IV. Testing Methods 1. Test of the mass percentage of indium powder in the negative electrode active material layer In the inert atmosphere of the glove box, the sulfide all-solid-state battery (electrochemical device) was disassembled, the indium-containing negative electrode was removed, the negative electrode active material layer was peeled off from the indium-containing negative electrode, the negative electrode active material layer was dissolved with acid (nitric acid-hydrofluoric acid mixed acid or aqua regia), and the mass percentage of indium powder in the negative electrode active material layer was measured and calculated using inductively coupled plasma optical emission spectrometry (ICP-OES).

[0113] 2. Areal density test of indium metal layer In the inert atmosphere of a glove box, disassemble the sulfide all-solid-state battery (electrochemical device), remove the indium-containing anode, peel off the composite layer of lithium metal and indium metal from the indium-containing anode, and cut a 1cm section from the composite layer. 2 For samples of a certain size, dissolve the sample in an acid (a mixture of nitric acid and hydrofluoric acid or aqua regia), and then measure and calculate the 1cm value using inductively coupled plasma optical emission spectrometry (ICP-OES). 2 The mass of indium (in mg) in a sample of a certain size, and the mass of indium relative to 1 cm³. 2 The ratio of is the areal density of the indium layer.

[0114] 3. Test of the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer. In the inert atmosphere of a glove box, disassemble the sulfide all-solid-state battery (electrochemical device), remove the indium-containing anode, peel off the composite layer of lithium metal and indium metal from the indium-containing anode, and cut a 1cm section from the composite layer. 2 For samples of a certain size, dissolve the sample in an acid (a mixture of nitric acid and hydrofluoric acid or aqua regia), and then measure and calculate the 1cm value using inductively coupled plasma optical emission spectrometry (ICP-OES). 2 The mass of lithium and indium in a sample of a certain size was determined, and the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer was obtained through further calculations.

[0115] 4. Mass test of indium per unit area in indium-containing anodes In the inert atmosphere of a glove box, disassemble the sulfide all-solid-state battery (electrochemical device), remove the indium-containing negative electrode, and cut a 1cm section from the indium-containing negative electrode. 2 For samples of a certain size, dissolve the sample in an acid (a mixture of nitric acid and hydrofluoric acid or aqua regia), and then measure and calculate the 1cm value using inductively coupled plasma optical emission spectrometry (ICP-OES). 2 The mass of indium in a sample of a certain size (in mg) is the mass of indium per unit area in an indium-containing negative electrode.

[0116] 5. Quality testing of positive electrode active material per unit area in the positive electrode In the inert atmosphere of a glove box, disassemble the sulfide all-solid-state battery (electrochemical device), remove the positive electrode, and cut a 1cm section from the positive electrode. 2 A sample of a certain size was placed in xylene to dissolve the positive electrode active material layer. The insoluble current collector was removed, and the xylene was dried at 150°C to constant weight, yielding a dried powder of the positive electrode active material layer. Thermogravimetric analysis was performed on the dried powder by heating to 600°C for 2 hours, cooling to room temperature, and weighing the residual powder, denoted as M1 (mg). Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to analyze the elemental composition and content of the residual powder. The composition of the positive electrode active material was determined by analyzing the elemental composition and content data. Based on this composition and M1, the mass M2 (mg) of the positive electrode active material was calculated. M2 is related to 1 cm⁻¹. 2 The ratio is the mass of the positive electrode active material per unit area in the positive electrode.

[0117] 6. Average particle size Dv50 test of silicon active materials At least five transverse cuts were made along the thickness direction of the negative electrode active material layer using a focused ion beam (FIB) to obtain at least five flat cross-sections. The cross-sections were then observed using a scanning electron microscope (SEM). A 30 μm × 30 μm test area was randomly selected from each cross-section, and the average particle size Dv50 of the silicon active material in the test area was measured. The arithmetic mean of the at least five cross-sections was then calculated, which is the average particle size Dv50 of the silicon active material.

[0118] 7. Electron conductivity test of indium-containing anodes The four-probe DC method is employed, specifically including: (1) The indium-containing negative electrode to be tested is stamped into a square sheet of regular size (2cm×2cm). The average thickness d (unit cm) is measured and recorded multiple times at different positions of the square sheet sample using a thickness gauge. (2) Using a four-probe tester, the four probes are arranged in a straight line with equal spacing of 1 mm. A small DC current I (unit A) of known size is injected into the square sample through the outer current probe. At the same time, the voltage drop ΔU (unit V) generated between the two probes when the current I flows is measured through the inner voltage probe. (3) Based on the measured voltage drop ΔU and injection current I, calculate the sheet resistance R of the square sheet sample using the following formula. s (Unit: Ω) R s = k×(ΔU / I); Where k is the probe coefficient, and k≈π / ln2≈4.532; Then, the electronic conductivity σ (in S / cm) of the square sheet sample (i.e., the indium-containing electrode) is calculated according to the following formula: σ = 1 / (R) s ×d).

[0119] 8. Volume expansion rate test of indium-containing anode The thickness of the indium-containing anode was measured using a laser displacement sensor and recorded as h0. A sulfide all-solid-state battery was then assembled using the indium-containing anode. After 100 charge-discharge cycles, the sulfide all-solid-state battery was disassembled, the indium-containing anode was removed, and its thickness was measured using a laser displacement sensor and recorded as h1. The volume expansion rate H (%) of the indium-containing anode was calculated using the following formula: H(%) = [(h1-h0) / h0] × 100%; The above charge-discharge cycle is as follows: In an environment of 25°C, the sulfide all-solid-state battery is charged at a constant current of 0.1 C to 4.5V, charged at a constant voltage to the cutoff current of 0.05C, and then discharged at a constant current of 0.1C to 3.0V. This constitutes one charge-discharge cycle.

[0120] 9. Cycle capacity retention test of sulfide all-solid-state batteries In a 25℃ environment, the sulfide all-solid-state battery was charged to 4.5V at a constant current of 0.1C, charged to the cutoff current of 0.05C at a constant voltage, and then discharged to 3.0V at a constant current of 0.1C. This constitutes one charge-discharge cycle. This cycle was repeated 100 times. The discharge capacity and charge capacity of the first cycle and the discharge capacity of the 100th cycle were recorded. The experiment was repeated 5 times, and the average value was taken. The cycle capacity retention rate (%) was calculated according to the following formula: Cycle capacity retention (%) = (average discharge capacity at the 100th cycle / average discharge capacity at the first cycle) × 100%.

[0121] 10. Voltage plateau test of indium-containing negative electrode A half-cell (Li | LPSCl | indium-containing anode) was assembled using lithium foil, an indium-containing anode (counter electrode), and Li6PS5Cl (LPSCl). Within a defined voltage window (for Li...),... + / Li is 0.01V-2.0V), and discharge (lithiation / alloying) and charge (delithiation / dealloying) with a constant current of 0.1C. Record the relationship between specific capacity and voltage during the discharge process. The first plateau that appears during the discharge process is the voltage plateau of the indium-containing anode. At the same time, record the range of the voltage plateau (i.e. the range between the minimum and maximum voltage of the voltage plateau), in V. V. Examples It should be noted that, in the specific embodiments of this application, a sulfide all-solid-state battery is used as an example of an electrochemical device to explain this application, but the electrochemical device of this application is not limited to a sulfide all-solid-state battery.

[0122] Unless otherwise specified, all reagents, materials, and instruments used in the following examples and comparative examples are commercially available. Furthermore, unless otherwise specified, "parts" and "%" refer to mass measurements.

[0123] In the following examples and comparative examples, the use of some reagents and materials is as follows: Indium powder, 325 mesh, Hunan Zhongcai Shengte New Material Technology Co., Ltd.; Silicon powder with an average particle size Dv50=600nm was obtained by ball milling 1μm Maclean S909158 silicon powder and then screening it. Silicon carbide (SiC), with an average particle size Dv50 of 600 nm, was obtained by ball milling 600-800 nm Maclean S799162 silicon carbide and then screening. Silica (SiO), with an average particle size Dv50 = 600 nm, was obtained by ball milling 2000 mesh Maclean S742347 silica and then screening. Tin powder, 200 mesh, T822990, McLean; Vapor-grown carbon fiber, BH, Henan Kelaiwei Nano Carbon Materials Co., Ltd.; Polyacrylic acid (PAA), P822497, McLean; Polyisobutylene (PIB), N100, BASF.

[0124] Example 1 This embodiment provides an indium-containing anode, comprising an anode current collector (copper foil), an anode active material layer, a lithium metal layer (lithium foil), and an indium metal layer (indium foil). The anode active material layer is located between the anode current collector and the lithium metal layer, and the lithium metal layer is located between the anode active material layer and the indium metal layer. The anode active material layer comprises indium powder, anode active material (silicon active material, silicon powder), anode conductive agent (vapor-grown carbon fiber, VGCF), and anode binder (polyacrylic acid, PAA). Based on the mass of the anode active material layer, the mass percentage of indium powder is w%, w=10.0, and the areal density of the indium metal layer is p mg / cm³. 2 p=2.7, w×p=27; The ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In=2:1. The thickness of the indium metal layer (indium foil) is 5μm, and the thickness of the lithium metal layer (lithium foil) is 6μm. The average particle size Dv50 of the silicon active material (silicon powder) is 600 nm. Based on the mass of the negative electrode active material layer, the mass ratio of the negative electrode active material (silicon active material, silicon powder) is 82%; the thickness of the negative electrode active material layer is 35 μm. This embodiment also provides a sulfide all-solid-state battery (electrochemical device), including the above-mentioned indium-containing negative electrode, positive electrode and electrolyte. The positive electrode includes a positive electrode active material (LiCoO2), and the electrolyte is a sulfide solid electrolyte (lithium-sulfur-phosphorus-chloride fast ion conductor, Li6PS5Cl). The mass of indium per unit area in the indium-containing anode is a mg / cm³. 2 Given a = 3.0, the mass of the positive electrode active material (LiCoO2) per unit area in the positive electrode is b mg / cm³. 2 b=20.0, a / b=0.15; The preparation method of the above-mentioned sulfide all-solid-state battery (electrochemical device) includes the following steps: 1. Preparation of indium-containing anodes (1) The negative electrode active material (silicon active material, silicon powder), indium powder, negative electrode conductive agent (vapor-grown carbon fiber, VGCF) and negative electrode binder (polyacrylic acid, PAA) were mixed in a mass ratio of 82:10:2:6. Deionized water was added, and the mixture was stirred at 2000 rpm for 120 min using a planetary mixer to obtain a negative electrode slurry with a solid content of 25 wt%. An 8µm copper foil was used as the negative electrode current collector. The negative electrode slurry was uniformly coated on one surface of the negative electrode current collector. After drying at 85℃ for 12 h, cold pressing at 30 MPa, and cutting, a negative electrode with a negative electrode active material layer on one side was obtained for later use. The thickness of the negative electrode active material layer was 25 μm. (2) In an argon-protected glove box, take 5µm thick indium foil and 6µm thick lithium foil, and use a roller press to composite the indium foil and lithium foil at 25℃ and 5MPa pressure to obtain a Li / In alloy interface layer. (3) In an argon-protected glove box, the lithium-containing side of the Li / In alloy interface layer is placed close to the negative electrode active material layer of the negative electrode prepared in step (1), and composited by a roller press at 25°C and 20 MPa pressure to obtain an indium-containing negative electrode. 2. Preparation of the positive electrode The positive electrode active material LiCoO2, sulfide solid electrolyte (lithium-sulfur-phosphorus-chloride fast ion conductor, Li6PS5Cl), positive electrode conductive agent (vapor-grown carbon fiber, VGCF), and positive electrode binder (polyisobutylene, PIB) were mixed in a mass ratio of 75:21:2:2. Pxylene (PX) was added, and the mixture was stirred evenly under vacuum to obtain a positive electrode slurry with a solid content of 45 wt%. A 9 µm aluminum foil was used as the positive electrode current collector, and the positive electrode slurry was uniformly coated onto one surface of the current collector. After drying, cold pressing, and cutting, a positive electrode with a single-sided positive electrode active material layer of 120 μm thickness was obtained.

[0125] 3. Preparation of electrolytes The electrolyte is obtained by cold pressing a lithium-sulfur-phosphorus-chloride fast ion conductor (Li6PS5Cl) into a 60μm film at 100 MPa. 4. Preparation of sulfide all-solid-state batteries (electrochemical devices) The above-prepared positive electrode, electrolyte, and indium-containing negative electrode (the indium metal layer on its surface is close to the active material layer of the positive electrode) are stacked in sequence, encapsulated in an aluminum-plastic film, and subjected to isostatic pressure at 300 MPa for 360 s to obtain a sulfide all-solid-state battery.

[0126] Examples 2-7 and Comparative Examples 1-6 The differences between Examples 2-7 and Comparative Examples 1-6 and Example 1 are the mass percentage (w%) of indium powder in the negative electrode active material layer and the areal density (p mg / cm³) of the metallic indium layer. 2 The differences are shown in Table 1, while the rest are consistent with Example 1. The mass content of the negative electrode conductive agent (vapor-grown carbon fiber, VGCF) and the negative electrode binder (polyacrylic acid, PAA) in the negative electrode active material layer remains constant. The mass ratio of indium powder to negative electrode active material (silicon powder) is adjusted to achieve the w values ​​shown in Table 1 for each example or comparative example. The thickness of the indium layer in the indium-containing negative electrode is adjusted to achieve the p values ​​shown in Table 1 for each example or comparative example. Based on this, the Li:In ratio (the ratio of the amount of lithium in the lithium layer to the amount of indium in the indium layer) is adjusted to remain constant, as shown in Table 1; the thickness of the negative electrode active material layer in the indium-containing negative electrode is adjusted to maintain the a value as shown in Table 1 for each example or comparative example. Comparative Example 6 uses tin powder with an average particle size Dv50 = 600 nm instead of indium powder in Example 1. The tin powder with an average particle size Dv50 = 600 nm is obtained by ball milling 200 mesh McLean T822990 tin powder and screening. Examples 8-11 and Comparative Example 7 Examples 8-11 and Comparative Example 7 differ from Example 1 in that the ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer (Li:In) is different, as shown in Table 2. All other aspects are the same as in Example 1. The Li:In ratio was adjusted as shown in Table 2 by adjusting the thickness of the lithium metal layer in the indium-containing anode.

[0127] Examples 12-17 The difference between Examples 12-17 and Example 1 lies in the mass of indium per unit area (a mg / cm²) in the indium-containing anode. 2 The mass of positive electrode active material per unit area in the positive electrode, b mg / cm³ 2 The differences are shown in Table 3, while the rest are consistent with Example 1. The thickness of the negative electrode active material layer in the indium-containing negative electrode was adjusted to make example a as shown in Table 3. The mass ratio of the sulfide solid electrolyte (lithium-sulfur-phosphorus-chloride fast ion conductor, Li6PS5Cl), the positive electrode conductive agent (vapor-grown carbon fiber, VGCF), and the positive electrode binder (polyisobutylene, PIB) remained constant, and the amount of positive electrode active material LiCoO2 was adjusted to make example b as shown in Table 3.

[0128] Examples 18-19 The difference between Examples 18 and 19 and Example 1 is that the types of silicon active materials are different, as shown in Table 4. All other aspects are the same as in Example 1.

[0129] Table 1. Condition parameters and performance test results for Examples 1-7 and Comparative Examples 1-6 As shown in Table 1, the indium-containing anode of this application can improve the electronic conductivity of the anode and the cycle capacity retention of the sulfide all-solid-state battery, as well as reduce the volume expansion rate of the anode.

[0130] Table 2. Condition parameters and performance test results for Examples 1, 8-11 and Comparative Example 7. Figure 1 The diagram shows the specific capacity and voltage relationship of the indium-containing negative electrode in Example 9 during the discharge process.

[0131] From Table 2 and Figure 1 It is understood that the indium-containing anode of this application can improve the electronic conductivity of the anode and the cycle capacity retention rate of the sulfide all-solid-state battery, as well as reduce the volume expansion rate of the anode.

[0132] Table 3. Condition parameters and performance test results for Examples 1, 12-17 As shown in Table 3, the indium-containing anode of this application can improve the electronic conductivity of the anode and the cycle capacity retention of the sulfide all-solid-state battery, as well as reduce the volume expansion rate of the anode.

[0133] Table 4. Condition parameters and performance test results for Examples 1, 18-19 As shown in Table 4, the indium-containing anode of this application can improve the electronic conductivity of the anode and the cycle capacity retention of the sulfide all-solid-state battery, as well as reduce the volume expansion rate of the anode.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. An indium-containing negative electrode, characterized in that, The electrode comprises a negative electrode current collector, a negative electrode active material layer, a lithium metal layer, and an indium metal layer. The negative electrode active material layer is located between the negative electrode current collector and the lithium metal layer, and the lithium metal layer is located between the negative electrode active material layer and the indium metal layer. The negative electrode active material layer includes indium powder, and the mass percentage of indium powder is w% based on the mass of the negative electrode active material layer. The areal density of the indium metal layer is p mg / cm³. 2 , 5≤w×p≤50.

2. The indium-containing negative electrode as described in claim 1, characterized in that, At least one of the following conditions (1)-(3) must be satisfied: (1) 12 ≤ w × p ≤ 36; (2)2.0≤w≤15.0； (3)1.0≤p≤4.0。 3. The indium-containing negative electrode as described in claim 1, characterized in that, At least one of the following conditions (1)-(2) must be satisfied: (1) The ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In=(0.5-4):1; (2) The negative electrode active material layer further includes at least one of the following: negative electrode active material, negative electrode conductive agent, and negative electrode binder.

4. The indium-containing negative electrode as described in claim 3, characterized in that, At least one of the following conditions (1)-(2) must be satisfied: (1) The ratio of the amount of lithium in the lithium metal layer to the amount of indium in the indium metal layer is Li:In=(1.2-3):1; (2) The negative electrode active material includes silicon active material.

5. The indium-containing negative electrode as described in claim 4, characterized in that, At least one of the following conditions (1)-(2) must be satisfied: (1) The silicon active material includes at least one of Si material, silicon-carbon composite material, and silicon-oxygen composite material; (2) The average particle size Dv50 of the silicon active material is 300-2500 nm.

6. The indium-containing negative electrode as described in claim 1, characterized in that, The voltage plateau of the indium-containing negative electrode is 0.55-0.70V under the condition that the ratio of the amount of lithium element in the lithium metal layer to the amount of indium element in the indium metal layer is Li:In=(1.2-3):

1.

7. An electrochemical device, characterized in that, It includes an indium-containing negative electrode, a positive electrode, and an electrolyte as described in any one of claims 1-6, wherein the positive electrode includes a positive electrode active material.

8. The electrochemical device as described in claim 1, characterized in that, At least one of the following conditions (1)-(3) must be satisfied: (1) The mass of indium per unit area in the indium-containing negative electrode is a mg / cm³. 2 The mass of the positive electrode active material per unit area in the positive electrode is b mg / cm³. 2 , 0.05≤a / b≤0.30; (2) The positive electrode also includes a sulfide solid electrolyte; (3) The electrolyte includes sulfide solid electrolytes.

9. The electrochemical device as described in claim 8, characterized in that, At least one of the following conditions (1)-(3) must be satisfied: (1) 0.12 ≤ a / b ≤ 0.20; (2)1.0≤a≤5.0； (3)10.0≤b≤30.0； (4) The sulfide solid electrolyte includes Li6PS5Cl, Li6PS5Br, and Li 10 GeP2S 12 Li 10 SnP2S 12 Li4SiS4, Li7P3S 11 Li6PS5I, Li 10 SiP2S 12 At least one of them.

10. An electronic device, characterized in that, Includes the electrochemical device as described in any one of claims 7-9.

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