Secondary battery

Abstract

This invention provides a secondary battery comprising a positive electrode, a negative electrode, and an electrolyte layer, wherein: the negative electrode is composed of a conductive current collector, a negative electrode active material, and a non-alkali metal monovalent ion conductor; the secondary battery is a sodium secondary battery or a lithium secondary battery. The secondary battery of this invention, such as an alkali metal secondary battery, is more stable under environmental conditions, easier to manufacture, less expensive, has improved rate performance, and significantly increased cycle life.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology. Specifically, this invention relates to a secondary battery. More specifically, this invention relates to an alkali metal secondary battery. Background Technology

[0002] Lithium / sodium alkali metal secondary batteries, as a form of chemical energy storage, are characterized by high energy density and long lifespan. With industry development, solid-state electrolytes and high specific capacity anodes have become the future directions for secondary batteries.

[0003] Sulfide and halide solid electrolytes possess excellent properties such as high ionic conductivity, making them the preferred materials for future solid-state batteries. However, alkaline ionic sulfides require stringent preparation environments and are more sensitive to moisture than other cationic electrolytes. Furthermore, solid electrolytes themselves lack electronic conductivity. To ensure stable battery operation, a relatively high proportion of electrolyte (typically >20% by weight) is needed in the electrodes to guarantee continuous ion / cell transport within the electrodes.

[0004] Currently, inorganic solid-state electrolytes can be further classified into lithium superionic conductors (LISICON), sodium superionic conductors (NASICON), argyrodite, perovskite, antiperovskite, and garnet types. Sulfide solid-state electrolytes have attracted significant attention due to their high ionic conductivity, such as Li... + Ionic conductors: LiPS5Cl, Li3PS4, LiSnS4, Li3BO3, Li4SiO4, Li7P3S 11 Sodium ion conductor Na3PS 4、 Na3SbS4, Na 11 Sn2SbS 12 .

[0005] Cu + and Ag + Early ionic conductor materials were primarily solid electrolytes that were extensively studied, commonly using Cu6PS5X and Ag6PS5X (X = Cl, Br, I), constructing related Cu structures through homogeneous ion transport. + and Ag +Secondary batteries. See JP49007169-A, CN104851473-A, and Journal of Non-Crystalline Solids, 2019, 521, 119476; Journal of Physics and Chemistry of Solids, 2003, 64, 1261; or Research progress on sodium ion sulfide solid electrolytes, Energy Storage Science and Technology, 2020, 9, 1266.

[0006] Therefore, there is an urgent need for a solid electrolyte that can be used in alkali metal secondary batteries, which is more stable and easier to prepare under environmental conditions, requires only a small amount of addition to adapt to the volume effect of the negative electrode, and significantly improves the cycle life of alkali metal secondary batteries. Summary of the Invention

[0007] The purpose of this invention is to provide a secondary battery, especially an alkali metal secondary battery, which is more stable and easier to prepare under environmental conditions, inexpensive, has improved rate performance, and significantly improved cycle life.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution.

[0009] This invention provides a secondary battery comprising a positive electrode, a negative electrode, and an electrolyte layer, wherein:

[0010] The negative electrode is composed of a conductive current collector, a negative electrode active material, and a non-alkali metal monovalent ion conductor.

[0011] The secondary battery is a sodium secondary battery or a lithium secondary battery.

[0012] The inventors of this application unexpectedly discovered that when a battery is prepared using non-alkali metal copper and / or silver ion conductors as the initial electrolyte in the negative electrode, copper and / or silver ions can be replaced by alkali metal ions during the battery formation process to form a lithium / sodium ion-conducting solid electrolyte in situ. The copper and / or silver layer formed at the electrolyte / negative electrode interface during the formation process can homogenize electron / ion transport in the negative electrode, inhibit the growth of lithium / sodium dendrites, and increase the critical current density for the operation of the alkali metal secondary battery.

[0013] Preferably, in the secondary battery of the present invention, the non-alkali metal monovalent ion conductor is capable of ionizing Cu. + Compounds of ions and / or capable of ionizing Ag + Compounds containing ions.

[0014] Preferably, in the secondary battery of the present invention, the non-alkali metal monovalent ion conductor is selected from Cu6PS5Cl, Cu6PS5Br, Cu6PS5I, Cu3PS4, and Cu7P3S.11 , CuCl, Cu2SO4, Ag6PS5Cl, Ag6PS5Br, Ag6PS5I, Ag3PS4, Ag7P3S 11 And one or more of AgCl.

[0015] Preferably, in the secondary battery of the present invention, the weight ratio of the non-alkali metal monovalent ion conductor to the negative electrode active material is non-alkali metal monovalent ion conductor: negative electrode active material = 1: (9-99).

[0016] Preferably, in the secondary battery of the present invention, the surface of the conductive current collector is modified with an inactive conductive coating.

[0017] Preferably, in the secondary battery of the present invention, the inactive conductive coating is composed of carbon-based materials, alloy materials or metals.

[0018] Preferably, in the secondary battery of the present invention, when the secondary battery is a sodium secondary battery, the negative electrode active material includes one or more of the following materials: hard carbon, soft carbon and antimony oxide; and the conductive current collector includes aluminum foil or carbon-coated aluminum foil.

[0019] Preferably, in the secondary battery of the present invention, when the secondary battery is a lithium secondary battery, the negative electrode active material includes one or more of the following materials: graphite, hard carbon, soft carbon, silicon-carbon, silicon, silicon-tin based materials; and the conductive current collector includes copper foil or carbon-coated copper foil.

[0020] Preferably, in the secondary battery of the present invention, when the secondary battery is a sodium secondary battery, the positive electrode comprises one or more of the following positive electrode active materials: sodium cobaltate, sodium manganate, sodium ferrite, sodium vanadium phosphate, and Prussian white.

[0021] Preferably, in the secondary battery of the present invention, when the secondary battery is a lithium secondary battery, the positive electrode comprises one or more of the following positive electrode active materials: NCM ternary positive electrode material, NCA ternary positive electrode material, LFP lithium iron phosphate, LMO lithium manganese oxide, LNMO lithium nickel manganese oxide, lithium-rich manganese-based positive electrode material, and lithium sulfide.

[0022] Preferably, in the secondary battery of the present invention, when the secondary battery is a sodium secondary battery, the electrolyte layer comprises, but is not limited to, Na6PS5Cl, Na6PS5Br, Na6PS5I, Na3PS4, and Na7P3S. 11 One or more of them.

[0023] Preferably, in the secondary battery of the present invention, when the secondary battery is a lithium secondary battery, the electrolyte layer includes, but is not limited to, Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3PS4, and Li7P3S. 11 One or more of them.

[0024] Preferably, in the secondary battery of the present invention, the electrolyte layer comprises Cu6PS5Cl, Cu6PS5Br, Cu6PS5I, Cu3PS4, and Cu7P3S. 11 , CuCl, Cu2SO4, Ag6PS5Cl, Ag6PS5Br, Ag6PS5I, Ag3PS4, Ag7P3S 11 And one or more of AgCl.

[0025] In some specific embodiments of the present invention, the non-alkali metal monovalent ion conductor of the present invention is prepared and composited in the negative electrode by methods such as grinding, liquid phase mixing, chemical and physical deposition, and there are no particular limitations.

[0026] The working principle of the secondary battery of the present invention is as follows:

[0027] After the positive electrode / electrolyte layer / negative electrode is stacked and pressed together, it is charged. In the negative electrode, the non-alkali metal ion conductors such as non-alkali metal copper and / or silver ions are replaced by alkali metal lithium and / or sodium ions. Copper and / or silver ions are deposited at the interface of electrolyte / negative electrode materials, and lithium and / or sodium ions continue to react with the negative electrode active material.

[0028] The present invention has the following beneficial effects:

[0029] The secondary battery of this invention exhibits higher stability under atmospheric conditions and allows for increased capacity utilization of the negative electrode active material, especially with extremely low electrolyte content (i.e., very low content of non-alkali metal monovalent ion conductors). This is primarily attributed to the Li released from the lithium / sodium-containing positive electrode through an electrochemical process. + and / or Na + Substitution of Cu in copper and / or silver ion conductors + and / or Ag + This process achieves the formation of an alternative electrolyte layer, thereby inducing the deposition of Cu and / or Ag at the electrolyte / anode interface, forming a functional interface layer that improves electronic conductivity and inhibits lithium / sodium dendrite formation. Attached Figure Description

[0030] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0031] Figure 1 This shows a scanning electron microscope (SEM) image of the negative electrode cross-section in Example 3 of the present invention, in which the interface layer was constructed by the electrochemical method.

[0032] Figure 2 A scanning electron microscope image of the negative electrode cross-section is shown in Comparative Example 2;

[0033] Figure 3 The charging curve of the secondary battery prepared in Example 3 of the present invention at a current density of 0.1C rate is shown.

[0034] Figure 4 The charging curve of the secondary battery prepared in Comparative Example 2 at a current density of 0.1C is shown. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0036] Example 1

[0037] In a dry environment with a dew point of -40℃, 10 mg of Na6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. NaCoO2 and Na6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was weighed and placed on one side of the electrolyte sheet, and kept under a pressure of 360 MPa for 10 min. Hard carbon and AgI were mixed evenly in a mortar at a mass ratio of 98:2 to form a composite negative electrode. 30 mg of this mixture was weighed and placed on the other side of the electrolyte sheet. An Al current collector was then attached to the surface, and the mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a1.

[0038] Example 2

[0039] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Graphite and AgI were mixed evenly in a mortar at a mass ratio of 98:2 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a2.

[0040] Example 3

[0041] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Silicon and Cu6PS5Cl were mixed evenly in a mortar at a mass ratio of 98:2 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a3.

[0042] Figure 1 This image shows a scanning electron microscope (SEM) photograph of the negative electrode interface constructed by the electrochemical method in Example 3 of the present invention. Figure 1 The SEM image in image a shows an intermediate layer at the electrolyte / Si anode interface. Figure 1 b)- Figure 1 Further analysis of the EDS spectra of Si, S, and Cu elements in d) reveals that, due to the presence of Li on the positive electrode side... + The Cu in Cu6PS5Cl at the negative electrode migrates towards the negative electrode side, causing Cu to... + Upon leaving the S-containing electrolyte portion, a Cu-enriched layer forms at the interface through reduction. The original Cu6PS5Cl transforms into Li6PS5Cl, thus eliminating the Cu signal in the EDS. The Cu at the interface significantly improves interfacial contact and electron transport.

[0043] Figure 3 The charging curve of the secondary battery prepared in Example 3 of the present invention at a rate of 0.1C is shown. The battery charge-discharge curve is smooth and normal, the coulombic efficiency is not abnormal, and the reversible specific capacity of the battery is 195 mAh / g.

[0044] Example 4

[0045] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Silicon and Ag7P3S11 were mixed evenly in a mortar at a mass ratio of 97:3 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and then a Cu current collector was attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a4.

[0046] Example 5

[0047] In a dry environment with a dew point of -40℃, 10 mg of Na6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. NaCoO2 and Na6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was weighed and placed on one side of the electrolyte sheet, and kept under a pressure of 360 MPa for 10 min. Hard carbon and Ag6PS5Br were mixed evenly in a mortar at a mass ratio of 95:5 to form a composite negative electrode. 30 mg of this mixture was weighed and placed on the other side of the electrolyte sheet. An Al current collector was then attached to the surface, and the mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a5.

[0048] Example 6

[0049] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Graphite and Cu7P3S... 11 Mix the electrolytes in a mortar at a mass ratio of 95:5 to form a composite negative electrode. Weigh 30 mg of the electrolyte and place it on the other side of the electrolyte sheet. Maintain the pressure at 360 MPa for 100 min. Then attach a Cu current collector to the surface and maintain the pressure at 10 MPa for 5 min. The resulting secondary battery is denoted as a6.

[0050] Example 7

[0051] In a dry environment with a dew point of -40℃, 10 mg of Cu6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Graphite and Cu6PS5I were mixed evenly in a mortar at a mass ratio of 95:5 to form a composite negative electrode. 30 mg of this mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a7.

[0052] Example 8

[0053] In a dry environment with a dew point of -40℃, 10 mg of Na6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. NaCoO2 and Na6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was weighed and placed on one side of the electrolyte sheet, and kept under a pressure of 360 MPa for 10 min. Hard carbon and Ag3PS4 were mixed evenly in a mortar at a mass ratio of 98:2 to form a composite negative electrode. 30 mg of this mixture was weighed and placed on the other side of the electrolyte sheet. An Al current collector was then attached to the surface, and the mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a8.

[0054] Example 9

[0055] In a dry environment with a dew point of -40℃, 10 mg of Na6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. NaCoO2 and Na6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was weighed and placed on one side of the electrolyte sheet, and kept under a pressure of 360 MPa for 10 min. Hard carbon and Ag6PS5Cl were mixed evenly in a mortar at a mass ratio of 95:5 to form a composite negative electrode. 30 mg of this mixture was weighed and placed on the other side of the electrolyte sheet. An Al current collector was then attached to the surface, and the mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a9.

[0056] Example 10

[0057] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Silicon and Cu6PS5Br were mixed evenly in a mortar at a mass ratio of 9:1 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a10.

[0058] Example 11

[0059] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Silicon and Cu2SO4 were mixed evenly in a mortar at a mass ratio of 97:3 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as a11.

[0060] Comparative Example 1

[0061] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Graphite and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 95:5 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as b1.

[0062] Comparative Example 2

[0063] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of the mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Silicon and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 98:2 to form a composite negative electrode. 30 mg of the mixture was placed on the other side of the electrolyte sheet, and then a Cu current collector was attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as b2.

[0064] Figure 2 A scanning electron microscope (SEM) image of the negative electrode interface in Comparative Example 2 of the present invention is shown. Figure 2 The SEM image in (a) shows good contact between the electrolyte and the interface. Figure 2 b)- Figure 2 Further analysis of the EDS spectra of Si and S elements in c) reveals that there is no intermediate interface layer, and the interfaces between the Si and S regions are clearly distinguishable.

[0065] Figure 4 The charging curve of the secondary battery prepared by Comparative Example 2 of the present invention is shown at a 0.1C rate. The battery charge-discharge curve is normal, but due to the low electrolyte content, the reversible specific capacity of the battery is only 67 mAh / g.

[0066] Comparative Example 3

[0067] In a dry environment with a dew point of -40℃, 10 mg of Li6PS5Cl was weighed and placed in a 10 mm diameter PTFE sleeve, and kept under a pressure of 360 MPa for 10 min to obtain a solid electrolyte sheet. LiNi 0.8 Co 0.1 Mn 0.1 O2 and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite positive electrode. 30 mg of this mixture was placed on one side of the electrolyte sheet and kept under a pressure of 360 MPa for 10 min. Silicon and Li6PS5Cl were mixed evenly in a mortar at a mass ratio of 7:3 to form a composite negative electrode. 30 mg of this mixture was placed on the other side of the electrolyte sheet, and a Cu current collector was then attached to the surface. The mixture was kept under a pressure of 100 MPa for 5 min. The resulting secondary battery is denoted as b3.

[0068] Secondary battery short circuit test

[0069] The secondary batteries of Examples 1-12 and Comparative Examples 1-3 were subjected to constant current charging at a current density of 2 mA / cm² in dry environments with a dew point of 25°C and -40°C. 2 After charging for one hour, observe the voltage of the secondary battery. If the voltage is 0V, it is determined to be in a short-circuit state.

[0070] First reversible specific capacity and 100-cycle capacity retention test

[0071] In a dry environment with a dew point of -40°C, the secondary battery of the example was first pre-charged and discharged at a rate of 0.1C under a test pressure of 100 MPa and an environment of 60°C, and the first reversible specific capacity was recorded. Subsequently, a low-rate charge-discharge cycle of 0.2C was performed, and the capacity retention rate of the 100th cycle was calculated based on the ratio of the discharge capacity of the first 0.2C cycle to that of the 100th cycle.

[0072] Table 1. First-time reversible capacity and capacity retention after 100 cycles for the examples and comparative examples

[0073] Serial Number Electrolyte layer Positive electrode active material Negative electrode active material + current collector The electrolyte in the negative electrode (i.e., a non-alkali metal monovalent ion conductor). Electrolyte content (wt%) in the negative electrode First reversible specific capacity (mAh / g) Capacity retention rate after 100 cycles (%) a1 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al AgI 2 144 82 a2 <![CDATA[Li6PS5Cl]]> NCM Graphite + Cu AgI 2 182 91 a3 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Cu6PS5Cl]]> 2 195 93 a4 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Ag7P3S 11 ]]> 3 196 88 a5 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al <![CDATA[Ag6PS5Br]]> 5 144 87 a6 <![CDATA[Li6PS5Cl]]> NCM Graphite + Cu <![CDATA[Cu7P3S 11 ]]> 5 181 94 a7 <![CDATA[Cu6PS5Cl]]> NCM Graphite + Cu <![CDATA[Cu6PS5I]]> 5 179 93 a8 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al <![CDATA[Ag3PS4]]> 2 146 91 a9 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al <![CDATA[Ag6PS5Cl]]> 5 142 96 a10 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Cu6PS5Br]]> 10 130 91 a11 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Cu2SO4]]> 3 179 90 b1 <![CDATA[Li6PS5Cl]]> NCM Graphite + Cu <![CDATA[Li6PS5Cl]]> 5 53 78 b2 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Li6PS5Cl]]> 2 67 73 b3 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Li6PS5Cl]]> 30 80 92

[0074] Note: The term "electrolyte content in the negative electrode (wt%)" in Table 1 refers to the weight percentage of the non-alkali metal monovalent ion conductor based on the total weight of the electrolyte (i.e., non-alkali metal monovalent ion conductor) and the negative electrode active material.

[0075] Table 1 shows that the alkali metal secondary battery of the present invention can effectively exert the reversible capacity of the battery with a very low content (5%). As can be seen from the comparison of b2 and b3, if a conventional electrolyte such as Li6PS5C1 is added to the negative electrode, its content needs to be increased to a very high percentage (e.g., to 30%) in order to achieve a high initial capacity and subsequent cycle stability.

[0076] Table 2 High-current short-circuit conditions in the examples and comparative cases

[0077] Serial Number Electrolyte types Positive electrode active material Negative electrode active material + current collector Non-alkali metal monovalent ionic conductors High current short circuit a1 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al AgI No short circuit a2 <![CDATA[Li6PS5Cl]]> NCM Graphite + Cu AgI No short circuit a3 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Cu6PS5Cl]]> No short circuit a4 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Ag7P3S 11 ]]> No short circuit a5 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al <![CDATA[Ag6PS5Br]]> No short circuit a6 <![CDATA[Li6PS5Cl]]> NCM Graphite + Cu <![CDATA[Cu7P3S 11 ]]> No short circuit a7 <![CDATA[Cu6PS5Cl]]> NCM Graphite + Cu <![CDATA[Cu6PS5I]]> No short circuit a8 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al <![CDATA[Ag3PS4]]> No short circuit a9 <![CDATA[Na6PS5Cl]]> <![CDATA[NaCoO2]]> Hard carbon + Al <![CDATA[Ag6PS5Cl]]> No short circuit a10 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Cu6PS5Br]]> No short circuit a11 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Cu2SO4]]> No short circuit b1 <![CDATA[Li6PS5Cl]]> NCM Graphite + Cu <![CDATA[Li6PS5Cl]]> Short circuit b2 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Li6PS5Cl]]> Short circuit b3 <![CDATA[Li6PS5Cl]]> NCM Silicon + Cu <![CDATA[Li6PS5Cl]]> Short circuit

[0078] Table 2 shows that the alkali metal secondary battery of the present invention has an effect on improving the negative electrode rate and exhibits advantages in short-circuit resistance during charging.

Claims

1. A secondary battery comprising a positive electrode, a negative electrode, and an electrolyte layer, wherein: The negative electrode is composed of a conductive current collector, a negative electrode active material, and a non-alkali metal monovalent ion conductor. The secondary battery is a sodium secondary battery or a lithium secondary battery.

2. The secondary battery according to claim 1, wherein, The non-alkali metal monovalent ion conductor is capable of ionizing Cu. + Compounds of ions and / or capable of ionizing Ag + Compounds containing ions.

3. The secondary battery according to claim 1, wherein, The non-alkali metal monovalent ionic conductor is selected from Cu6PS5Cl, Cu6PS5Br, Cu6PS5I, Cu3PS4, and Cu7P3S. 11 , CuCl, Cu2SO4, Ag6PS5Cl, Ag6PS5Br, Ag6PS5I, Ag3PS4, Ag7P3S 11 And one or more of AgCl.

4. The secondary battery according to claim 1, wherein, The weight ratio of the non-alkali metal monovalent ion conductor to the negative electrode active material is non-alkali metal monovalent ion conductor : negative electrode active material = 1 : (9-99).

5. The secondary battery according to claim 1, wherein, The surface of the conductive current collector is modified with an inactive conductive coating.

6. The secondary battery according to claim 5, wherein, The inactive conductive coating is composed of carbon-based materials, alloy materials, or metals.

7. The secondary battery according to claim 1, wherein, When the secondary battery is a sodium secondary battery, the negative electrode active material includes one or more of the following materials: hard carbon, soft carbon, and antimony oxide; and the conductive current collector includes aluminum foil or carbon-coated aluminum foil.

8. The secondary battery according to claim 1, wherein, When the secondary battery is a lithium secondary battery, the negative electrode active material includes one or more of the following materials: graphite, hard carbon, soft carbon, silicon-carbon, silicon, silicon-tin based materials; and the conductive current collector includes copper foil or carbon-coated copper foil.

9. The secondary battery according to claim 1, wherein, When the secondary battery is a sodium secondary battery, the positive electrode contains one or more of the following positive electrode active materials: sodium cobaltate, sodium manganate, sodium ferrite, sodium vanadium phosphate, and Prussian white.

10. The secondary battery according to claim 1, wherein, When the secondary battery is a lithium secondary battery, the positive electrode contains one or more of the following positive electrode active materials: NCM ternary positive electrode material, NCA ternary positive electrode material, LFP lithium iron phosphate, LMO lithium manganese oxide, LNMO lithium nickel manganese oxide, lithium-rich manganese-based positive electrode material, and lithium sulfide. Preferably, when the secondary battery is a sodium secondary battery, the electrolyte layer comprises Na6PS5Cl, Na6PS5Br, Na6PS5I, Na3PS4, and Na7P3S. 11 One or more of them; Preferably, when the secondary battery is a lithium secondary battery, the electrolyte layer comprises Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3PS4, and Li7P3S. 11 One or more of them; Preferably, the electrolyte layer comprises Cu6PS5Cl, Cu6PS5Br, Cu6PS5I, Cu3PS4, and Cu7P3S. 11 , CuCl, Cu2SO4, Ag6PS5Cl, Ag6PS5Br, Ag6PS5I, Ag3PS4, Ag7P3S 11 And one or more of AgCl.

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