A high energy density lithium battery and applications thereof

Abstract

The embodiment of the present application relates to a kind of high energy density lithium battery and its application.High energy density lithium battery includes: positive electrode structure, lithium-containing negative electrode structure, liquid electrolyte or solid electrolyte;Positive electrode structure includes positive electrode active material Li x M y O z S m F n And / or its composite;The mass ratio of positive electrode active material in positive electrode structure is greater than or equal to 92%, and the positive electrode active material surface load is greater than or equal to 20 mg / cm 2 ;Positive electrode structure also includes conductive carbon;Lithium-containing negative electrode structure includes negative electrode material, and the thickness of negative electrode material ranges from 5 to 160 μm;The mass of active lithium contained in the unit area of single side of lithium-containing negative electrode structure is greater than or equal to 0.26 mg / cm 2 ;The ratio of the mass of electrolyte and / or solid electrolyte to battery capacity is 0.5-2.0 g / Ah;High energy density lithium battery has wide potential electrochemical window, wherein the upper limit of charge cut-off voltage is between 4.5 V and 5.8 V, and the lower limit of discharge cut-off voltage is between 0.5 V and 2.0 V;Under wide potential electrochemical window, the mass energy density of high energy density lithium battery is 500-1300 Wh / kg, and the volume energy density is 900-2500 Wh / L.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a high-energy-density lithium battery and its applications. Background Technology

[0002] Lithium-ion batteries boast the highest energy density among all commercially available batteries and are widely used in consumer electronics, electric vehicles, and large-scale energy storage. In recent years, the rapid development of various industries has placed higher demands on the energy density and safety performance of batteries.

[0003] The comprehensive evaluation of lithium-ion battery performance includes factors such as mass energy density, volumetric energy density, cycle performance, rate performance, safety, temperature adaptability, engineering index, cost, self-discharge rate, and service life. Among these, energy density is the most important, corresponding to the duration of operation per unit power of the energy-consuming equipment. Currently, the highest energy density of commercially available lithium-ion battery cells can reach around 360Wh / kg. However, with the increasing demand for longer driving range in electric vehicles and the expansion of commercial lithium-ion batteries in applications such as electric aircraft (e.g., electric and hybrid aircraft), battery energy density needs to be above 500Wh / kg to achieve practical value. Therefore, high-energy-density batteries are the future trend. However, how to achieve even higher energy density lithium-ion battery cells is a pressing technical problem that needs to be solved in the commercialization process.

[0004] From a materials perspective, theoretically, lithium metal has the highest energy density among anodes. The cathode material determines the overall energy density of the battery system. To achieve an energy density of over 500 Wh / kg, theoretically calculated potential cathodes include: air-based cathodes such as fluorine and oxygen; non-rechargeable primary cathode materials such as fluorinated graphite; phase-transition cathode materials such as MnO2 and FeS2; sulfur cathodes; and LiCoO2 and Li(Ni)2 cathodes. x Co y Mn z O2, Li 1+x M 1-x Lithium oxide cathodes, such as O2 and Li2MnO3, are examples. Among these types of cathodes, lithium oxide cathodes have lower energy densities at conventional charge-discharge voltages compared to the other types. Phase-transition lithium-free cathode materials have high energy densities but poor cycle performance. Primary batteries with high energy densities, such as fluorinated graphite, cannot undergo charge-discharge cycles. Lithium-air and lithium-sulfur batteries are frequently mentioned in published research papers, but they also have some problems. The following section will analyze lithium-sulfur and lithium-air batteries in detail.

[0005] When only considering the positive and negative electrode materials, the theoretical capacity of lithium-sulfur batteries is 2654 Wh / kg, but this is still far from practical application, and some unresolved issues remain, such as the poor electronic conductivity of sulfur and lithium sulfide (insulators, 10). -30 The lithium-air battery exhibits several challenges, including low energy density (S / cm), the shuttle effect of lithium polysulfides (dissolution of active materials, self-discharge, low energy efficiency), and problems with metallic lithium (low chemical stability, safety, uneven deposition of solvents such as lithium dendrites, dead lithium, and pulverization). Technically, this cathode suffers from difficulties in achieving high loading rates, excessive electrolyte injection, poor electrode structure and rate capability, and significant volume expansion. Low cathode loading and high electrolyte injection make it difficult to increase energy density, while low rate capability and large volume changes result in extremely poor cycle performance, making it difficult to achieve the energy density levels of lithium-ion batteries. Lithium-air batteries have a higher theoretical capacity, reaching 5217 Wh / kg, and lithium fluoride even reaches 6294 Wh / kg. However, their practical application is more difficult than that of lithium-sulfur batteries. The energy density of lithium-air battery devices is also difficult to increase, and they suffer from low energy efficiency (excessive polarization), poor cycle performance, and low rate capability. The redox reaction of the air electrode occurs on the carrier, and factors such as the carrier's quality, morphology, pore size, porosity, and specific surface area significantly affect the energy density, rate capability, and cycle performance of lithium-air batteries. The discharge products Li₂O₂ and Li₂O can block oxygen diffusion channels, significantly increasing the polarization voltage (>1V) and thus reducing energy density. The redox and decomposition reactions of charge-discharge products during lithium-air battery discharge are difficult and require catalyst assistance. Lithium-air batteries operate in open environments, where water vapor in the air permeates to the negative electrode, corroding metallic lithium and affecting the battery's discharge capacity and lifespan. Carbon dioxide reacts with discharge products to form lithium carbonate, which has very poor electrochemical reversibility. Generally, oxygen-selective permeation membranes are developed to prevent water vapor permeation and electrolyte evaporation, but adding a permeation membrane further reduces the battery's energy density. Adding additional gas protection, generation, or supply devices will lead to even greater reductions in energy density. Therefore, both lithium-sulfur batteries and lithium-air batteries present their own challenges and difficulties in practical use, necessitating the exploration of alternative solutions.

[0006] Currently, common lithium-containing oxide cathodes are charged and discharged within a relatively narrow voltage range. This is to ensure cycle stability and lifespan while meeting basic energy density requirements, and also to meet the power demands of electrical appliances. However, the energy density they can achieve is relatively low. There have been a few reports on charging and discharging lithium-containing cathode materials over a wider voltage range. For example, Yujuan Zhao et al. (Investigation on the Overlithiation Mechanism of LiCoO2 Cathode for Lithium Ion Batteries) compared the charge and discharge cycles of lithium cobalt oxide cathodes under multiple voltage ranges, including 1.0-4.3V, 1.2-4.3V, 2.0-4.3V, and 3.0-4.3V. Their study found that charging and discharging lithium cobalt oxide cathode materials undergo irreversible phase transitions within a wide potential cutoff voltage range. Therefore, existing battery systems have significant problems in charging and discharging over a wider voltage range. They cannot achieve reversible charging and discharging cycles over a wide voltage range that have practical value, and thus cannot achieve high-energy-density battery systems. This severely limits the commercial application of lithium-ion batteries, especially in the field of electric aircraft.

[0007] Therefore, while existing lithium-ion, lithium-sulfur, and lithium-air battery material systems possess high energy densities, their overall performance is limited by manufacturing processes, making it difficult to achieve a practically usable battery system with high energy density. As for lithium-ion batteries, currently commercially available batteries only achieve an energy density of 360Wh / kg, which is insufficient to meet the demands of long-range electric vehicles or electric aircraft. Achieving higher energy densities, including both mass and volumetric energy densities, remains a significant challenge for current technologies.

[0008] In summary, the existing battery systems are currently unable to achieve the actual production of high-quality energy density cells, let alone achieve both high mass energy density and high volumetric energy density. Furthermore, it is difficult to achieve stable cycle performance. Summary of the Invention

[0009] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is how to improve the mass energy density and volumetric energy density of lithium battery cells. The purpose is to provide a high energy density lithium battery and its application. Through the construction of a new battery system and the optimization and improvement of process design parameters, ultra-high mass energy density and volumetric energy density can be achieved.

[0010] Therefore, in a first aspect, embodiments of the present invention provide a high energy density lithium battery, comprising: a positive electrode structure, a lithium-containing negative electrode structure, a liquid electrolyte and / or a solid electrolyte;

[0011] The positive electrode structure includes the positive electrode active material Li. x M y O z S m F n And / or its composite materials, wherein 1 / 4≤x / z≤2, 1 / 2≤x / y≤6, 0≤m / y≤5 / 2, 0≤n / y≤3, and M is one or more of Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Ni, Co, Mn, Cu, Fe, Ga, Ge, As, Se, Mo, Zn, Y, Zr, Nb, Tc, Ru, Pb, Pd, Rh, Ag, Cd, Sb, Ba, La, Ta, W, Os, and Pb, wherein when M is only Na, Mg, K, Ca, Co, Ba, Rh, or Os, m and n are not simultaneously 0; the mass ratio of the positive electrode active material in the positive electrode structure is ≥92%, and the surface loading of the positive electrode active material is ≥20 mg / cm³. 2 ;

[0012] The positive electrode structure also includes conductive carbon;

[0013] The lithium-containing anode structure includes an anode material, which comprises one or more of metallic lithium, lithium alloy, composite metallic lithium, pre-lithiated silicon-based anode, and pre-lithiated carbon-based anode; wherein the thickness of the anode material ranges from 5 to 160 μm; and the mass of active lithium contained in a unit area on one side of the lithium-containing anode structure is ≥0.26 mg / cm³. 2 ;

[0014] The mass ratio of the electrolyte and / or solid electrolyte to the battery capacity is 0.5-2.0 g / Ah;

[0015] The high-energy-density lithium battery has a wide potential electrochemical window, wherein the upper limit of the charging cutoff voltage is between 4.5V and 5.8V, and the lower limit of the discharging cutoff voltage is between 0.5V and 2.0V; within the wide potential electrochemical window, the high-energy-density lithium battery has a gravimetric energy density of 500-1300Wh / kg and a volumetric energy density of 900-2500Wh / L.

[0016] Preferably, after the first discharge cycle of the high-energy-density lithium battery under the wide potential electrochemical window, the active lithium content in the lithium-containing anode structure is reduced by more than 10% compared to the active lithium content in the original lithium-containing anode structure before the first discharge cycle.

[0017] Preferably, the upper limit of the charging cutoff voltage of the wide potential electrochemical window is between 4.62V and 5.0V, and the lower limit of the discharging cutoff voltage is between 1.0V and 1.5V.

[0018] Preferably, the conductive carbon has an electronic conductivity of 10. 2 Conductive carbon with a strength of S / cm or higher; preferably, the conductive carbon includes one or more of carbon nanotubes, graphene, conductive carbon black, carbon fiber, and conductive graphite; preferably, the content of the conductive carbon is ≥0.005wt%.

[0019] Preferably, the composite material of the positive electrode active material further includes one or more of the following: oxides, fluorides, sulfides, polymers, ionic conductors, and weak acids;

[0020] Preferably, the oxide includes one or more of the following: manganese dioxide, magnesium oxide, lanthanum oxide, zirconium oxide, tungsten oxide, tin oxide, aluminum oxide, titanium oxide, cerium oxide, and niobium oxide; the fluoride includes one or more of the following: fluorinated graphite, iron fluoride, copper fluoride, titanium fluoride, chromium fluoride, cobalt fluoride, and bismuth fluoride; the sulfide includes one or more of the following: cobalt sulfide, nickel sulfide, sublimed sulfur, molybdenum sulfide, sodium sulfide, and magnesium sulfide; the polymer includes one or more of the following: polyacrylonitrile, polyphosphazene, polyurethane, and polycarbonate; the ionic conductor includes one or more of the following: lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich layered oxide, lithium nickel manganese oxide, lithium aluminum titanium phosphate, and aluminum phosphate; and the weak acid includes one or more of the following: ammonium bicarbonate, ammonium carbonate, oxalic acid, benzoic acid, boric acid, and citric acid.

[0021] Preferably, the positive electrode active material Li x M y O z S m F n In the given conditions, 1≤x≤2, 0<y≤1, 2≤z≤6, 0<m≤1 / 2, 0<n≤1, and M is two or more of Ni, Co, Mn, Al, Cu, Fe, Mg, Ti, Zn, Cr, V, Zr, and Nb; preferably, the compaction density of the electrode sheet in this positive electrode structure is >2.2 g / cm³. 3 .

[0022] Preferably, the positive electrode structure and the negative electrode structure each further include a current collector, which includes one or more of copper foil, aluminum foil, stainless steel foil, titanium foil, or flexible composite current collector;

[0023] Preferably, the thickness of the copper foil is ≤9μm, the thickness of the aluminum foil is ≤15μm, the thickness of the stainless steel foil is ≤10μm, and the thickness of the titanium foil is ≤9μm;

[0024] Preferably, the flexible composite current collector is an ultralight flexible composite current collector, which consists of an intermediate layer containing a polymer and multiple conductive layers, wherein the multiple conductive layers include at least two conductive layers located on both sides of the intermediate polymer layer.

[0025] More preferably, the intermediate polymer layer comprises one or more of a dense film, a porous film, or a fiber film, with a thickness of 1-20 μm; the conductive layer is made of one or more of a metallic conductive material, a non-metallic conductive material, or a composite conductive material, with a thickness of 0.005-3 μm.

[0026] Preferably, the intermediate polymer layer is made of one or more of PET, PP, PE, and PI; the conductive layer is made of one or more of conductive carbonaceous materials, conductive ceramics, Al, Cu, Ni, Ti, Sn, Ag, Au, Fe, and stainless steel.

[0027] Preferably, a passivation layer is provided between the negative electrode material and the current collector interface of the negative electrode; the passivation layer includes one or more of elemental metals, carbonaceous materials, and metal oxides, and has a thickness of 10 nm-2 μm;

[0028] Preferably, the passivation layer is a lithium-loving passivation layer, which can be prepared on the surface of the negative electrode current collector by any one of magnetron sputtering, electrochemical deposition, chemical vapor deposition, physical vapor deposition or solution impregnation.

[0029] Preferably, the solid electrolyte includes one or more of the following: polymer solid electrolyte, inorganic solid electrolyte, and composite solid electrolyte formed by polymer and inorganic compound;

[0030] The polymer solid electrolyte comprises one or more of the following: polyolefins, polyethers, polynitriles, polyesters, polyacrylates, polycarbonates, polyurethanes, polyureas, polysulfones, and polysiloxane electrolytes; preferably, the polymer solid electrolyte comprises one or more of the following: polyethylene oxide, polypropylene oxide, polyethylene glycol dimethyl ether, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, polyvinyl chloride, polymethyl methacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, polystyrene, polyvinylidene fluoride-hexafluoropropylene, polyvinyl alcohol, polyvinyl alcohol formal, polymethyl methacrylate, polyethylene glycol methacrylate, and polyetheramines.

[0031] The inorganic solid electrolyte includes one or more of the following: oxide, sulfide, halide, phosphate, nitride, NASICON type, LISICON type, garnet type, perovskite type, and anti-perovskite type electrolytes; preferably, the inorganic solid electrolyte includes: Li 1+x Al x Ti2-x (PO4)(0≤x≤0.5), Li 1+x Al x Ge 2-x (PO4)(0≤x≤0.5), LLZO and its modified derivatives, Li 7-x La3Zr 2-x Ta x O 12 (0≤x≤2), Li3Zr2Si2(PO4) 12 LLTO and its modified derivatives, LiPON, Li3N, Li3OCl, Li 10 GeP2S 12 LiPS and its modified derivatives, Li₂ZrCl₆, Li₃InCl₆, Li₃YCl₆, Li x ScCl 3+x (1≤x≤4), Li3ErCl6;

[0032] In the composite solid electrolyte, the polymer is the polymer solid electrolyte, and the inorganic compound includes the inorganic solid electrolyte and / or inert inorganic materials; preferably, the inert inorganic materials include Al2O3, SiO2, TiO2, ZrO2, BaTiO3, and SrBi4Ti4O. 15 One or more of the following: carbon nanotubes;

[0033] Preferably, the solid electrolyte further comprises a lithium salt;

[0034] Preferably, the solid electrolyte is a composite solid electrolyte composed of a polyester electrolyte and the inorganic compound;

[0035] The electrolyte comprises: a lithium salt used as an electrolyte, a solvent, and additives;

[0036] Preferably, the electrolyte is a high-voltage resistant liquid electrolyte with an electrochemical window oxidation potential ≥ 4.5V;

[0037] Preferably, the solvent is an ester solvent, and the additive is one or more of the following: carbonates, sulfonamide salts, carboxylic acid esters, sulfates, sulfites, sulfonyl lactones, borate esters, nitriles, and inorganic salts.

[0038] Preferably, the amount of electrolyte injected is in the range of 0.8 g / Ah to 1.8 g / Ah.

[0039] Preferably, the lithium battery further includes a separator, which includes one or more of the following: polyethylene separator, polypropylene separator, composite separator formed of double or multiple layers of polyethylene and polypropylene, polyaramid separator, cellulose separator, polyvinylidene fluoride separator, and polyimide separator.

[0040] Preferably, the diaphragm has a single-sided coating or a double-sided coating, wherein the double-sided coating is a symmetrical or asymmetrical coating; the coating material includes one or more of inorganic ion conductor materials, inorganic lithiophilic materials, polymer materials, or organic-inorganic composite materials; the coating material is in the form of powder particles or a thin film, and the coating thickness is 0.02μm-10μm;

[0041] Preferably, the inorganic material in the inorganic ionic conductor material, inorganic lithiophilic material, or organic-inorganic composite material includes one or more of oxides, phosphates, and silicon-carbon composite materials;

[0042] Preferably, the inorganic ionic conductor material includes one or more of LATP, LLZO, LiPON, LiPO3, and Li3N, and the inorganic lithiophilic material includes one or more of Si / C, Ag / C, Al2O3, and SiO2.

[0043] Preferably, the organic material in the polymer material or organic-inorganic composite material includes one or more of the following: PVDF, PVDF-HFP, PEO, PAN, PTFE, PMMA, PCA, PDMS, PEG, PEGMEA, PEGDA, PEC, PPC, PTMC, PVC, PCL, and PI;

[0044] Preferably, the organic-inorganic composite material includes PEO+LLZO, PEO+LAGP, PVDF+LLZO, PVDF+LLTO, PAN+LLZO, and PEO+SiO2 composite materials.

[0045] Preferably, the lithium battery further includes a lightweight encapsulation material, and preferably, the lightweight encapsulation material includes one or more of metals, alloys, polymers, and polymer-metal composite materials;

[0046] The high-energy-density lithium battery cell packaging form includes one or more of the following: button type, pouch type, cylindrical type, prismatic type, ellipsoidal type, spherical curved strip type, ribbon type, and linear type.

[0047] Preferably, the operating temperature range of the high-energy-density lithium battery is within -80℃ to 100℃; more preferably, it is 60℃ to 100℃, or -80℃ to -10℃.

[0048] Secondly, embodiments of the present invention provide a lithium battery pack or lithium battery module, including the high energy density lithium battery described in the first aspect above.

[0049] The high-energy-density lithium battery provided in this invention achieves the synergistic use of high-energy-density cathode materials and high-capacity lithium-containing anode materials through the combination of a cathode structure with a wide potential electrochemical window and a lithium-containing anode structure, thus constructing a high-energy-density battery material system. The cathode material of this invention has a crystal structure with strong extensibility and contains additional lithium storage sites, allowing lithium ions to continue entering tetrahedral sites after completely filling the octahedral sites. This enables the active lithium content in the lithium-containing anode to play a role, matching the expanded lithium capacity of the cathode material. While increasing the material capacity, it still maintains good reversibility, synergistically achieving a material-level energy density improvement. During charge-discharge cycles, this cathode material can continuously compensate for the loss of active lithium, extending the cycle performance of the cell system. The cathode system of this invention is a thick electrode system. By adopting the cathode system of this invention, due to its specific monoclinic / trigonal composite layered structure, in addition to the material itself having certain electronic conductivity characteristics, it can also promote the stability of the dispersion of conductive carbon mixed in the cathode structure, and can construct a good electronic conductivity network when conductive carbon is added. Furthermore, due to the additional lithium storage sites in the positive electrode structure, a negative electrode with a high lithium content can be used. Therefore, the active lithium content in the lithium battery system of this invention can exceed 0.26 mg / cm³. 2 With the above-described positive and negative electrode system, the present invention can meet the corresponding requirements using only a small amount of electrolyte. Furthermore, the lithium battery of the present invention has a wide potential electrochemical window, within which it exhibits high-quality energy density and volumetric energy density, and good electrochemical performance. Attached Figure Description

[0050] Figure 1 Li, the positive electrode material synthesized in this invention 1.2 N i 0.13 Co 0.13 Mn 0.54 O2 and Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2S 0.01 F 0.02 Charge-discharge cycle performance curves;

[0051] Figure 2 The above are charge-discharge cycle curves of the battery system shown in Example 1 in different charge-discharge ranges.

[0052] Figure 3 This is a graph showing the cycle performance of battery systems with different composite cathode materials in Example 2;

[0053] Figure 4 This is a charge-discharge curve of a battery system in Example 3 where the negative electrode and the negative electrode current collector have different passivation layers;

[0054] Figure 5 The above are charge-discharge curves of battery systems with different flexible composite current collectors in Example 4.

[0055] Figure 6 The graph shows the electrochemical performance of the soft-pack batteries with different coating layers in Example 5.

[0056] Figure 7 This is a graph showing the battery capacity curves when different electrolytes are used in Example 6;

[0057] Figure 8 This is a graph showing the electrochemical performance of the battery system prepared in Example 7 under charge-discharge cycles at 60°C.

[0058] Figure 9 This is a graph showing the capacity curve of the soft-pack battery after the coating thickness of the positive electrode material increased in Example 8.

[0059] Figure 10 This is a graph showing the capacity curves of the soft-pack batteries with different liquid injection volumes in Example 9;

[0060] Figure 11 This is a graph showing the capacity curves of pouch cells with different electrolytes added to the cathode material in Example 10.

[0061] Figure 12 This is a capacity curve of the soft-pack battery in Example 11;

[0062] Figure 13 This is a capacity curve of the soft-pack battery in Example 12;

[0063] Figure 14 The charge-discharge curves of the coin cell with mesophase carbon microspheres as the negative electrode in Comparative Example 1 are shown.

[0064] Figure 15 The charge-discharge curves of the battery system in Comparative Example 2, which uses a low proportion of positive electrode active material, low areal loading, and a silicon anode, are shown.

[0065] Figure 16 The charge-discharge curves of the battery system using lithium cobalt oxide cathode in Comparative Example 3 are shown. Detailed Implementation

[0066] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0067] This invention provides a high-energy-density lithium battery that can achieve ultra-high mass energy density and volumetric energy density. It should be noted that, in the context of this invention, the lithium battery is a lithium secondary battery, including lithium metal batteries and lithium-ion batteries.

[0068] During the research process, the applicant discovered that the key material components in lithium batteries play a crucial role. Comprehensively considering the multi-component system of lithium batteries is a technological path to achieving higher specific energy and greater safety. In batteries geared towards practical application, achieving high energy density in lithium battery cells is limited by both battery material and process parameter design. Simply improving the specific energy of battery materials or only improving battery process parameter design cannot achieve ultra-high specific energy rechargeable batteries. Therefore, to achieve a practical ultra-high energy density battery, this invention considers multiple factors, including improving the properties of individual materials, improving individual process technologies, the coupling effect between materials, matching materials and process technologies, and the compatibility between process parameter design and process parameters. Through substantial improvements to various important influencing factors in material and process parameter design, the high energy density battery of this invention has been realized.

[0069] In terms of materials, the single factors affecting battery energy density include the energy carried per unit mass / volume of active materials such as the positive and negative electrodes, and the mass or volume ratio of inactive materials such as electrolytes, conductive carbon, binders, current collectors, and encapsulation materials. Improving energy density can be achieved by increasing the specific capacity of the positive and negative electrode active materials, expanding the relative average voltage between the positive and negative electrodes, reducing the impurity content of the active materials, and improving the kinetic properties of inactive materials such as electronic and ionic conductivity. Because the materials contained in batteries are extremely complex, there are coupling effects between different materials, such as capacity matching between positive and negative electrode materials, compatibility between the positive electrode active material and the binder / conductive carbon, stability of the positive electrode-separator interface, interaction between the electrolyte and the positive and negative electrodes, and stability of the negative electrode-separator interface. Therefore, while improving the performance of each individual component material, it is also necessary to consider the interactions between different materials.

[0070] In terms of process design, the applicant considered that influencing factors generally include the ratio of active material / conductive carbon / binder, electrode thickness, compaction density, the N / P ratio of the negative electrode capacity to the positive electrode capacity, the amount of electrolyte injected or solid electrolyte used, the areal density of the separator, the mass of the current collector, the tabs, and the encapsulation materials. The core is to reduce the content of inactive materials while maintaining the electrochemical performance of the active materials. Therefore, methods such as increasing electrode thickness, increasing the proportion of active material in the electrode, increasing compaction, reducing the N / P ratio, reducing the amount of electrolyte injected, and using lighter current collectors, tabs, and encapsulation materials can be employed.

[0071] To overcome the bottleneck in the energy density of current commercial lithium batteries, this invention designs and optimizes battery system and process parameters based on battery material systems and cell technology, thereby achieving lithium batteries with ultra-high quality energy density and volumetric energy density.

[0072] Therefore, this invention provides a high-energy-density lithium battery, comprising: a positive electrode structure, a lithium-containing negative electrode structure, a liquid electrolyte and / or a solid electrolyte;

[0073] The positive electrode structure includes the positive electrode active material Li x M y O z S m F n And / or its composite materials, wherein 1 / 4≤x / z≤2, 1 / 2≤x / y≤6, 0≤m / y≤5 / 2, 0≤n / y≤3, and M is one or more of Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Ni, Co, Mn, Cu, Fe, Ga, Ge, As, Se, Mo, Zn, Y, Zr, Nb, Tc, Ru, Pb, Pd, Rh, Ag, Cd, Sb, Ba, La, Ta, W, Os, and Pb, wherein when M is only Na, Mg, K, Ca, Co, Ba, Rh, or Os, m and n are not simultaneously 0; more preferably, the positive electrode active material is Li x M y O z S m F n In the given information, 1≤x≤2, 0<y≤1, 2≤z≤6, 0<m≤1 / 2, 0<n≤1, and M is two or more of Ni, Co, Mn, Al, Cu, Fe, Mg, Ti, Zn, Cr, V, Zr, and Nb.

[0074] In cathode materials, the molar ratio of lithium to oxygen satisfies 1 / 4 ≤ x / z ≤ 2. This can be any value within the above range, such as 1 / 4, 1 / 2, 3 / 5, 4 / 5, 1, 6 / 5, 3 / 2, 2, etc., but is not limited to the listed values; other unlisted values ​​within this range also apply. Materials with lithium-oxygen molar ratios within the above range exhibit high specific energy when used as cathode materials in batteries, effectively improving the specific energy of the battery system without affecting cycle performance.

[0075] In cathode materials, the molar ratio of lithium to element M satisfies 1 / 2 ≤ x / y ≤ 6. This can be any value within the above range, such as 1 / 2, 3 / 5, 1, 5 / 3, 2, 3, 4, 5, 6, etc., but is not limited to the listed values; other unlisted values ​​within this range also apply. Materials with a lithium-to-element M molar ratio within the above range, when used as cathodes, can achieve both high energy density and good cycle performance.

[0076] In the cathode material, the molar ratio of sulfur to M satisfies 0 ≤ m / y ≤ 5 / 2. This ratio can be any value within the above range, such as 0.001, 0.01, 0.1, 0.5, 1, 1.5, 2, 2.5, etc., but is not limited to the listed values; other unlisted values ​​within this range also apply. A sulfur to M molar ratio within the above range can stabilize the material structure and improve cycle performance.

[0077] In the cathode material, the molar ratio of fluorine to metal (M) satisfies 0 ≤ n / y ≤ 3. This ratio can be any value within the above range, such as 0.001, 0.01, 0.1, 0.2, 0.5, 0.8, 1, 2, 2.5, 3, etc., but is not limited to the listed values; other unlisted values ​​within this range also apply. A fluorine-to-M molar ratio within the above range helps stabilize the material structure and improves cycle performance.

[0078] The mass ratio of positive electrode active material in the positive electrode structure is ≥92%, and the areal loading of positive electrode active material is ≥20 mg / cm³. 2 ;

[0079] To increase the capacity per unit area of ​​the positive electrode, the active material accounts for more than 92% of the total mass of the electrode material. Specifically, it can be 92%, 93%, 94%, 95%, 96%, 97%, or 97.5%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0080] To improve the capacity per unit area of ​​the positive electrode, the coating thickness of the active material can be increased, resulting in an active material surface loading of ≥20 mg / cm². 2 Specifically, it could be: 20.0 mg / cm³ 2 25.0 mg / cm 2 30.0 mg / cm 2 35.0 mg / cm 2 40.0 mg / cm 2 However, this does not apply to all values ​​listed; other unlisted values ​​within the same range also apply.

[0081] When using composite materials, the aforementioned positive electrode active material Li x M y O z S m F n In addition to containing the positive electrode active material Li x M y O z S m F n In addition, it also includes modified materials for composite with positive electrode active materials, including one or more of oxides, fluorides, sulfides, polymers, ionic conductors, and weak acids.

[0082] The oxides include one or more of the following: manganese dioxide, magnesium oxide, lanthanum oxide, zirconium oxide, tungsten oxide, tin oxide, aluminum oxide, titanium oxide, cerium oxide, and niobium oxide; the fluorides include one or more of the following: fluorinated graphite, iron fluoride, copper fluoride, titanium fluoride, chromium fluoride, cobalt fluoride, and bismuth fluoride; the sulfides include one or more of the following: cobalt sulfide, nickel sulfide, sublimed sulfur, molybdenum sulfide, sodium sulfide, and magnesium sulfide; the polymers include one or more of the following: polyacrylonitrile, polyphosphazene, polyurethane, and polycarbonate; the ionic conductors include one or more of the following: lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich layered oxide, lithium nickel manganese oxide, lithium aluminum titanium phosphate, and aluminum phosphate; the weak acids include one or more of the following: ammonium bicarbonate, ammonium carbonate, oxalic acid, benzoic acid, boric acid, and citric acid.

[0083] By adding modifying substances such as oxides, fluorides, sulfides, polymers, ionic conductors, and weak acids to the main active materials of composite materials, the cycle performance and safety performance of cathode materials can be further improved.

[0084] These modifying materials used for composite material modification can be added at the early, middle, and late stages of positive electrode active material synthesis, or at the finished product stage. Methods for adding modifying materials include: liquid-phase methods, such as co-precipitation and sol-gel methods; solid-phase methods, such as ball milling and sand milling; and gas-phase methods, such as chemical vapor deposition and physical vapor deposition. To maximize the high specific capacity advantage of the positive electrode active material, the content of the added modifying material can be 0-50% of the mass of the composite positive electrode material, for example: 1%, 2%, 5%, 8%, 10%, 20%, 30%, 40%, 50%, etc., but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0085] Because the positive electrode structure of this invention is a thick electrode structure, while traditional positive electrode sheets cannot achieve the preparation of large-area uniform thick electrodes due to factors such as the state of the positive electrode active material, slurry viscosity, and the proportion of conductive carbon. Due to the addition of composite positive electrode materials, this invention allows for a wider range of adjustable viscosity during slurry preparation, and the slurry exhibits stronger fluidity at high viscosities compared to homogeneous materials. The pH of the slurry is also more controllable. Furthermore, the unique microstructure of the composite positive electrode material also provides lubrication during the coating process.

[0086] The positive electrode structure also includes conductive carbon; specifically, the conductive carbon has an electronic conductivity of 10. 2 Conductive carbon with a strength of S / cm or higher; preferably, the conductive carbon includes one or more of carbon nanotubes, graphene, conductive carbon black, carbon fiber, and conductive graphite; preferably, the content of the conductive carbon is ≥0.005wt%.

[0087] The conductive carbon is preferably carbon nanotubes (CNTs), including one or more of single-walled and multi-walled carbon nanotubes. CNTs have high electronic conductivity, with a conductivity > 10. 3 It has a surface area of ​​S / cm and also has a high specific surface area.

[0088] The positive electrode structure with the active material ratio and areal loading of this invention is a thick electrode structure. Due to its high tortuosity and high ion diffusion path, the thick electrode will lead to a significant increase in battery polarization, making it impossible for the battery to perform normal charge and discharge cycles. By using conductive carbon with high conductivity, especially carbon nanotubes with high conductivity, a good conductive network is constructed to ensure the normal conductivity of the positive electrode, thereby ensuring that the lithium battery can perform normal charge and discharge cycles.

[0089] The combination of a cathode material with the aforementioned structure and a lithium-containing anode system can fully leverage the advantages of high capacity. Furthermore, during charge-discharge cycling within a wide potential window, it can receive active lithium from the anode at the end of the first discharge cycle, minimizing irreversible structural changes and ensuring the stability of the cathode material structure. This achieves asymmetric charge-discharge in the first cycle, significantly improving the battery's energy density. In subsequent charge-discharge cycles, the cathode material can continuously compensate for the loss of active lithium, thus ensuring the stability of cycle performance.

[0090] The lithium-containing anode structure includes an anode material, which may be one or more of metallic lithium, lithium alloy, composite metallic lithium, pre-lithiated silicon-based anode, or pre-lithiated carbon-based anode; wherein the thickness of the anode material ranges from 5 to 160 μm; preferably, the mass of active lithium contained in a unit area on one side of the lithium-containing anode structure is ≥0.26 mg / cm². 2 .

[0091] The aforementioned lithium metal can be one or more forms selected from lithium foil, lithium sheet, lithium rod, lithium wire, lithium strip, and lithium film. Using a lithium metal anode maximizes the specific capacity of the anode.

[0092] The aforementioned lithium alloy refers to an alloy material containing metallic lithium. To improve the specific capacity of the negative electrode active material and reduce the electrode thickness to promote ion transport, the lithium alloy negative electrode can be an alloy formed from one or more of Li and Sn, Sb, Si, Al, Mg, B, Zn / Na, Ca, and C. However, the solutions to achieve the present invention are not limited to the listed metals or non-metals; other unlisted elements that can further improve the specific capacity of the lithium alloy negative electrode are also applicable.

[0093] The aforementioned composite lithium metal refers to a mixture of inactive materials or partially active materials with lithium metal. To further improve the long-term cycle stability of the negative electrode active material, it is necessary to composite lithium metal. For example, one specific form of composite lithium metal is the preparation of a composite metal of Li and a carbon framework. However, the solutions that can realize the present invention are not limited to carbon frameworks; composite metal forms that can further improve the cycle stability of the negative electrode are also applicable. Composite lithium metal improves the cycle stability of the negative electrode by appropriately reducing the lithium content and reserving space for the deposition and dissolution of lithium metal in advance, thereby mitigating the volume change of the negative electrode.

[0094] The aforementioned pre-lithiated silicon-based or pre-lithiated carbon-based anodes refer to anodes in which some active lithium metal is added in advance to silicon-based or carbon-based anode materials or electrodes, forming anodes with partial delithiation capacity in their original state (uncharged / discharged state). Pre-lithiated silicon-based or carbon-based anodes are a type of lithium-containing anode, where the pre-placed lithium can compensate for the lithium required for a wide potential range of the positive electrode, while also mitigating the consumption of active lithium during the formation of the solid electrolyte interphase (SEI), thereby improving the cycle life of the anode.

[0095] To ensure that the negative electrode has an areal loading that matches that of the positive electrode, the thickness of the lithium-containing negative electrode active material layer ranges from 5 to 160 μm. Specifically, it can be any value within the above range, such as 5 μm, 6 μm, 8 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0096] Preferably, to ensure that the negative electrode has a matching areal loading with the positive electrode and to guarantee the construction of a high-energy-density battery system, the mass of active lithium loaded per unit area on one side of the lithium-containing negative electrode is ≥0.26 mg / cm². 2 Specifically, it can be any value within the above range, for example: 0.26 mg / cm³. 2 0.28 mg / cm 2 0.30 mg / cm 2 0.32 mg / cm 2 0.34 mg / cm 2 0.36 mg / cm 2 0.38 mg / cm 2 0.40 mg / cm 2 This applies to, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0097] The positive electrode structure and negative electrode structure of the present invention also include a current collector, which is one of an ultra-thin current collector or a flexible composite current collector. The ultra-thin current collector includes one or more of copper foil, aluminum foil, stainless steel foil, and titanium foil.

[0098] To reduce the mass ratio of the current collector in the entire electrode sheet, it is necessary to control the thickness of the metal foil. Preferably, the thickness of the copper foil is ≤9μm, the thickness of the aluminum foil is ≤15μm, the thickness of the stainless steel foil is ≤10μm, and the thickness of the titanium foil is ≤9μm.

[0099] To further reduce the mass proportion of the current collector in the entire electrode sheet, the flexible composite current collector is preferably an ultra-light flexible composite current collector, consisting of a polymer-containing intermediate layer and multiple conductive layers, wherein the multiple conductive layers include at least two conductive layers located on either side of the intermediate polymer layer. In a preferred embodiment, a polymer-containing intermediate layer and conductive layers on both sides can be used.

[0100] The current collector of the present invention is preferably a flexible composite current collector, wherein the intermediate polymer layer comprises one or more of a dense thin film, a porous thin film, or a fiber thin film; in order to reduce the mass ratio of inactive materials in the positive and negative electrode structures, the thickness of the intermediate polymer layer is 1-20 μm, for example, it can be: 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable. The conductive layer is made of one or more of a metallic conductive material, a non-metallic conductive material, or a composite conductive material. The composite conductive material includes various forms such as metal-metal composite, metal-non-metal composite, and non-metal-non-metal composite, but is not limited to the listed material types, and other commonly used conductive materials not listed are also applicable. The thickness of the conductive layer is preferably 0.005-3μm, for example, it can be: 0.005μm, 0.008μm, 0.01μm, 0.03μm, 0.05μm, 0.08μm, 0.1μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0101] In a preferred embodiment, the intermediate polymer layer is made of one or more of polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and polyimide (PI); the conductive layer is made of one or more of conductive carbonaceous materials, conductive ceramics, Al, Cu, Ni, Ti, Sn, Ag, Au, Fe, and stainless steel.

[0102] Since the composite current collector of this invention has a polymer layer in the middle, the conductive layers on both sides cannot be directly interconnected to conduct electrons. Therefore, the polymer of the composite current collector is preferably porous or fibrous. During the formation of the conductive layer, conductive channels can be formed inside the porous or fibrous film to facilitate the conduction of the conductive layers on both sides. The flexible composite current collector based on the above scheme has the lightest mass, which is beneficial to improving the energy density of the battery system.

[0103] Furthermore, in a preferred embodiment, the lithium battery of the present invention has a passivation layer between the negative electrode material and the current collector interface of the negative electrode. The passivation layer comprises one or more of elemental metals, carbonaceous materials, and metal oxides, with a thickness of 10 nm to 2 μm, which can be any specific value within the above range, such as 10 nm, 50 nm, 100 nm, 200 nm, 500 nm, 1 μm, or 2 μm. Preferably, the passivation layer is a lithium-affinity passivation layer, and particularly preferably, the passivation layer material is one or more of carbon, silicon, aluminum, and silver.

[0104] This invention aims to suppress the growth of lithium dendrites in the negative electrode during cycling, ensuring battery safety performance, and optimizing the design and structure by introducing a passivation layer at the interface between the negative electrode material and the negative electrode current collector. This passivation layer is prepared on the surface of the negative electrode current collector using any one of the following methods: magnetron sputtering, electrochemical deposition, chemical vapor deposition, physical vapor deposition, or solution impregnation.

[0105] In the positive electrode structure of this invention, the compaction density of the electrode sheet is >2.2 g / cm³. 3 To reduce the porosity of the positive electrode sheet and thus ensure improved conductivity and ion mobility even with low electrolyte usage, the compaction density of the positive electrode sheet needs to be maintained within a certain range. Therefore, through process parameter optimization, the final compaction density of the positive electrode sheet was determined to be >2.2 g / cm³. 3 For example, it could be: 2.3g / cm³ 3 2.4g / cm 3 2.6g / cm 3 2.8g / cm 3 3.0g / cm 3 However, this is not limited to the listed values; other unlisted values ​​within this range also apply. The high-density cathode of this invention is suitable for battery systems using trace amounts of electrolyte, ensuring normal charge-discharge cycling and significantly improving the energy density of the battery system.

[0106] Therefore, the mass ratio of the electrolyte and / or solid electrolyte to the battery capacity of this invention is optimized to 0.5-2.0 g / Ah through process parameters. As an inactive substance, reducing the mass of the electrolyte can directly increase the battery's energy density. Generally, a decrease in electrolyte content prevents the positive electrode material from being wetted, thus preventing the battery from undergoing normal charge-discharge cycles. This invention, through the establishment of a positive and negative electrode structure system, enables normal charge-discharge cycling even with trace amounts of electrolyte in the lithium battery system.

[0107] On the one hand, this invention reduces porosity by increasing the compaction density of the electrode, thereby reducing the required electrolyte volume. This is to reduce the porosity of the positive electrode sheet. On the other hand, the positive electrode material synthesized in this invention has the aforementioned structural formula, and in a preferred embodiment, it possesses a special sulfidated and fluorinated surface structure. This structure can chemically bond with salt or solvent molecules in the electrolyte, significantly increasing the wettability and wetting rate of the electrolyte after contact with it during battery assembly, forming a capillary effect in electrode electrolyte injection and reducing the injection volume. The capillary effect of conductive carbon can further reduce the injection volume. Simultaneously, the stable interface of the positive electrode can reduce interfacial side reactions during battery cycling, reducing electrolyte consumption and improving electrolyte retention. This invention employs a trace electrolyte combined with a high compaction density positive electrode structure, ensuring that the battery system proposed in this invention can undergo normal charge-discharge cycling and significantly improving the energy density of the battery system.

[0108] The lithium battery system of this invention can use liquid electrolyte and / or solid electrolyte.

[0109] Under the condition of using an electrolyte in the lithium battery system of the present invention: the electrolyte includes: lithium salt, solvent and additives used as electrolyte.

[0110] The lithium salt in the electrolyte can be selected from one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalate)borate (LiBOB), lithium difluorooxalateborate (LiODFB), and lithium peroxygenate (LiCIO4), and the lithium salt accounts for 10wt%-20wt% of the total mass of the electrolyte.

[0111] The electrolyte is a high-voltage resistant liquid electrolyte with an electrochemical window oxidation potential ≥4.5V. To ensure that the electrolyte does not decompose under high voltage and to form a stable positive electrode-electrolyte interface (CEI) or solid electrolyte interface (SEI) film, an ester solvent is used. Preferably, one or more of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl methyl carbonate (EMC), and / or fluorides of the above solvents are used, and preferably two or three of the above organic solvents are used. The above organic solvents account for 40wt%-85wt% of the total mass of the lithium battery electrolyte.

[0112] To improve the cycle life, safety, and rate performance of batteries, electrolyte additives are one or more of the following: carbonates, sulfonamide salts, carboxylic acid esters, sulfates, sulfites, sulfonyl lactones, borate esters, nitriles, and inorganic salts.

[0113] Preferably, the additive can be one or more of the following substances: vinylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, dialkyl carbonate, dibutyl carbonate, tributyl carbonate, vinyl sulfate, propylene sulfate, vinyl sulfite, propylene sulfite, butene sulfite, 4-methyl ethylene sulfate, 4-methyl ethylene sulfite, 4-methyl vinyl sulfite, 1,3-propanesulfonate lactone, 1,4-butanesulfonate lactone, 1,3-(1-propene)sulfonate lactone, diethyl(cyanomethyl)phosphonate, N,N-dimethylformamide, methanedisulfonate methylene, cyclohexylbenzene, hydrogenated biphenyl oxide, tris(trimethylsilane)phosphonite, tris(trimethylsilane)boronate, N,N' - Dimethyltrifluoroacetamide, tert-butylbenzene, adiponitrile, succinic anion, 3-hexenedionitrile, 1,2-bis(2-cyanoethoxy)ethane, 1,3-phenyleneacetonitrile, sulfur dioxide, carbon dioxide, lithium fluoride, lithium carbonate, lithium nitrate, potassium perchlorate, sodium perchlorate, propenyl-1,3-sulfonyl lactone, lithium sulfide, lithium sulfite, lithium sulfate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(trimethylsilylamino)imide, lithium bis(fluorosulfonyl)imide, lithium trifluoromethanesulfonate, tri(trifluoromethanesulfonyl)methyl lithium, lithium bis(perfluoroethylsulfonyl)imide, lithium (trifluoromethanesulfonyl)(n-perfluorobutylsulfonyl)imide, lithium (trifluoromethanesulfonyl)(fluorosulfonyl)imide, dihexyl borate, trimethoxyborane, trimethylborane, TEG, and other related products. Benzene, phenylacetone, anisole, 4-methyl-o-dimethoxybenzene, 4-fluorosubstituted o-dimethoxybenzene, 2,3,5,6-tetramethyl-p-dimethoxybenzene, 2,6-di-tert-butyl-1,4-benzoquinone, o-diphenylbenzene, N-methylpyrrole, 1,2-diphenylethane, diphenyl ether, 2,5-di-tert-butyl-1,4-benzoquinone, 4-tert-butyl-o-dimethoxybenzene, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tributyl phosphate, tris(2,2,2-trifluoroethyl) phosphate, (2,2,2-trifluoroethyl)diethyl phosphate, 3-(2,2,2-trifluoro)ethoxyphosphine, di(2,2,2-trifluoroethyl)methyl phosphate, hexamethylphosphononitrile, methyl difluoroacetate, ethyl difluoroacetate, methyl Additives such as fluorobutyl ether, potassium perfluorobutyl sulfonate, trifluoromethyl phosphorous acid, methyl chloroformate, fluoromethyl vinyl carbonate, difluoromethyl vinyl carbonate, trifluoromethyl vinyl carbonate, fluoroethyl acetate, bromobutyrolactone, fluorobenzene, N-methyl-2-pyrrolidone, fluorinated carbamate, hexamethylphosphoramide, pyridine, ethanolamine, tributylamine, 4-phenylbutylamine, thiocyanate, vinyl acetate, divinyl adipate, allyl methyl carbonate, 4-(N,N-2-methylamino)pyridine, 12-crown-4-ether, 18-crown-6-ether, heptamethyldisilazane, fluorinated ethers, silane compounds, trialkyl phosphates, and trioctyl phosphate, etc., constitute 1wt%-15wt% of the total mass of the lithium battery electrolyte.

[0114] To reduce the electrolyte's mass percentage in the entire cell while ensuring stable electrochemical performance, the electrolyte injection amount is maintained at 0.8-1.8 g / Ah, depending on the electrode compaction density. For example, it can be 1.8 g / Ah, 1.6 g / Ah, 1.4 g / Ah, 1.2 g / Ah, 1.0 g / Ah, 0.8 g / Ah, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable. In the battery system of this invention, the electrolyte injection amount can be trace electrolyte.

[0115] In this system, the lithium battery of the present invention also includes a separator, which may specifically include one or more of the following: polyethylene separator, polypropylene separator, composite separator formed of double or multiple layers of polyethylene and polypropylene, polyaramid separator, cellulose separator, polyvinylidene fluoride separator and polyimide separator.

[0116] The aforementioned diaphragm is preferably an ultrathin diaphragm, which may have a single-sided coating or a double-sided coating, wherein the double-sided coating is a symmetrical or asymmetrical interface coating; the coating material includes one or more of inorganic ion conductor materials, inorganic lithiophilic materials, polymer materials or organic-inorganic composite materials; the coating material is in the form of powder particles or thin film, and the coating thickness is 0.02μm-10μm;

[0117] The inorganic materials in the above-mentioned inorganic ionic conductor materials, inorganic lithiophilic materials, or organic-inorganic composite materials preferably include one or more of oxides, phosphates, and silicon-carbon composite materials;

[0118] The aforementioned inorganic ionic conductor materials preferably include one or more of lithium aluminum titanium phosphate (LATP), lithium aluminum germanium phosphate (LLZO), lithium phosphorus oxynitride nitrogen (LiPON), LiPO3, and Li3N; the aforementioned inorganic lithiophilic materials include one or more of the following: compounds or mixtures formed by silicon and carbon in any proportion (Si / C), compounds or mixtures formed by silver and carbon in any proportion (Ag / C), Al2O3, and SiO2.

[0119] The organic materials in the above-mentioned polymer materials or organic-inorganic composite materials may preferably include one or more of the following: polyvinylidene fluoride (PVDF), a mixture of polyvinylidene fluoride and hexafluoropropylene in any proportion (PVDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA), phosphonocarboxylic acid polymer (PCA), polydimethylsiloxane (PDMS), polyethylene glycol (PEG), polyethylene glycol methyl ether acrylate (PEGMEA), polyethylene glycol diacrylate (PEGDA), polyethylene carbonate (PEC), polypropylene carbonate (PPC), polytrimethylene carbonate (PTMC), polyvinyl chloride (PVC), polycaprolactone (PCL), and polyimide (PI);

[0120] Preferred organic-inorganic composite materials include: PEO + lithium lanthanum zirconium oxide (LLZO), PEO + lithium aluminum germanium phosphate (LAGP), PVDF + LLZO, PVDF + lithium lanthanum titanate (LLTO), PAN + LLZO, and PEO + SiO2 composite materials. Here, a composite material refers to a mixture of two substances in any proportion; for example, PEO + LLZO refers to a mixture of PEO and LLZO in any proportion.

[0121] To ensure more uniform coating, the coating material is in the form of powder particles or a thin film, which can be formed by coating or plating, with a coated separator being particularly preferred. The coated separator has superior liquid retention capacity, allowing for a lower liquid electrolyte injection volume, enabling the lithium battery cell to function normally even with a low injection volume of 0.5-2.0 g / Ah. Secondly, when the electrode area load is higher, the problem of lithium dendrite formation becomes more prominent; the separator of this invention has a superior ability to inhibit lithium dendrite growth. Furthermore, the separator of this invention also has higher thermal stability and increased electrolyte wettability. To ensure the coating function and minimize the proportion of the separator in the total cell mass, the coating thickness is between 0.02μm and 10μm. It can be any value within the above range, such as 0.02μm, 0.05μm, 0.1μm, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0122] The above-mentioned diaphragm has a highly uniform and thin interfacial coating, which can reduce the mass ratio of inactive materials in the battery cell.

[0123] Under the condition that a solid electrolyte is used in the lithium battery system of the present invention: the solid electrolyte may include one or more of the following: polymer solid electrolyte, inorganic solid electrolyte, and composite solid electrolyte formed by polymer and inorganic compound;

[0124] The polymer solid electrolyte includes one or more of the following: polyolefins, polyethers, polynitriles, polyesters, polyacrylates, polycarbonates, polyurethanes, polyureas, polysulfones, and polysiloxanes; preferably, the polymer solid electrolyte includes one or more of the following: polyethylene oxide, polypropylene oxide, polyethylene glycol dimethyl ether, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, polyvinyl chloride, polymethyl methacrylate, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, polystyrene, polyvinylidene fluoride-hexafluoropropylene, polyvinyl alcohol, polyvinyl alcohol formal, polymethyl methacrylate, polyethylene glycol methacrylate, and polyetheramines.

[0125] Inorganic solid electrolytes include one or more of the following: oxide, sulfide, halide, phosphate, nitride, NASICON type, LISICON type, garnet type, perovskite type, and anti-perovskite type electrolytes; preferably, the inorganic solid electrolyte includes: Li 1+x Al x Ti 2-x (PO4)(0≤x≤0.5), Li 1+x Al x Ge 2-x (PO4)(0≤x≤0.5), LLZO and its modified derivatives, Li 7-x La3Zr 2-x Ta x O 12 (0≤x≤2), Li3Zr2Si2(PO4) 12 LLTO and its modified derivatives, LiPON, Li3N, Li3OCl, Li 10 GeP2S 12 LiPS and its modified derivatives, Li₂ZrCl₆, Li₃InCl₆, Li₃YCl₆, Li x ScCl 3+x (1≤x≤4), Li3ErCl6; where LLZO refers to lithium lanthanum zirconate, and the modified series of derivatives refers to the doping or coating of LLZO, such as the doping of tantalum; LLTO refers to lithium lanthanum titanate, and the modified derivatives refer to the doping or coating of LLTO; LPS refers to a series of lithium phosphide sulfides synthesized based on Li2S and P2S5, and the derivatives refer to the doping or coating of LPS, such as the doping of elements such as Cl and Si.

[0126] In the composite solid electrolyte, the polymer is a polymer solid electrolyte, and the inorganic compound includes inorganic solid electrolytes and / or inert inorganic materials; the inert inorganic material is a bulk inorganic material that does not conduct lithium ions; preferably, the inert inorganic material includes Al2O3, SiO2, TiO2, ZrO2, BaTiO3, and SrBi4Ti4O3. 15 One or more of the following: carbon nanotubes;

[0127] Furthermore, solid electrolytes may also contain lithium salts;

[0128] Most preferably, the solid electrolyte is a composite solid electrolyte composed of polyester electrolyte and inorganic compound. This organic-inorganic composite form overcomes the problems of low mechanical strength and low ionic conductivity of pure polymer electrolytes, while also solving the problems of interfacial contact and difficult preparation of pure inorganic solid electrolytes.

[0129] For liquid electrolytes, the injection volume can be directly controlled to obtain the ratio of electrolyte mass to battery capacity. For solid electrolytes, this invention mainly reduces the electrolyte content by decreasing the thickness of the solid electrolyte. For pure inorganic solid electrolytes, ultra-thin solid electrolytes are mainly prepared through coating, plating, sputtering, etc. For polymer solid electrolytes and polymer-inorganic composite solid electrolytes, due to their better plasticity, ultra-thin solid electrolytes are prepared through hot pressing, cold pressing, extrusion, coating, casting, stretching, rolling, etc. For mixed solid-liquid electrolytes, it is a combination of the above two, the difference being that less single liquid electrolyte is added and the solid electrolyte film is thinner. The working principle is that ion channels are formed by the intermingling of liquid and solid in the mixed solid-liquid electrolyte.

[0130] The high-energy-density lithium battery of the present invention has a wide electrochemical potential window, wherein the upper limit of the charging cutoff voltage is not lower than 4.5V, specifically between 4.5V and 5.8V, and the lower limit of the discharging cutoff voltage is not higher than 2.0V, specifically between 0.5V and 2.0V. More preferably, the upper limit of the charging cutoff voltage is between 4.62V and 5.0V, and the lower limit of the discharging cutoff voltage is between 1.0V and 1.5V.

[0131] Preferably, the upper limit of the charging cutoff voltage can be 4.5V, 4.55V, 4.6V, 4.62V, 4.65V, 4.7V, 4.75V, 4.8V, 5.0V, 5.1V, 5.2V, 5.3V, 5.4V, 5.5V, 5.6V, 5.7V, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0132] Preferably, the lower limit of the discharge cutoff voltage can be 2.0V, 1.75V, 1.5V, 1.3V, 1.25V, 1.2V, 1.0V, 0.8V, 0.5V, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0133] The positive electrode structure of the present invention has a wide potential electrochemical window, which results in a high charging cut-off voltage and a low discharging cut-off voltage for the battery system. This allows the battery system to be charged and discharged over a wider range, thereby increasing battery capacity and ultimately greatly improving the energy density of the battery.

[0134] Within a wide potential electrochemical window, high-energy-density lithium batteries exhibit a mass energy density of 500-1300 Wh / kg and a volumetric energy density of 900-2500 Wh / L.

[0135] After the first discharge cycle of the high-energy-density lithium battery under the aforementioned wide potential electrochemical window, the active lithium content in the lithium-containing anode structure is reduced by more than 10% compared to the active lithium content in the original lithium-containing anode structure before the first discharge cycle.

[0136] The battery system of the present invention, when charged and discharged within the wide voltage range, reduces the content of active lithium in the negative electrode structure by more than 10% at the end of the first discharge cycle compared to the original negative electrode structure, thereby achieving compensation of active lithium by the negative electrode. This achieves asymmetric charge and discharge of the positive electrode in the first cycle, with the discharge capacity exceeding the charging capacity, thus significantly improving the energy density of the battery.

[0137] Preferably, in the negative electrode structure, the content of active lithium is reduced to 10%-75%, such as 10%, 11%, 12%, 15%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, but not limited to the values ​​listed.

[0138] The high-energy-density lithium battery of the present invention also includes a lightweight encapsulation material; preferably, the lightweight encapsulation material includes one or more of metals, alloys, polymers, and polymer-metal composite materials.

[0139] The high-energy-density lithium battery cell of the present invention is packaged in one or more of the following forms: button, pouch, cylindrical, prismatic, ellipsoidal, spherical curved strip, ribbon, and linear.

[0140] The operating temperature range of the high-energy-density lithium battery described above is within -80℃ to 100℃; preferably 60℃ to 100℃; or -80℃ to -10℃.

[0141] The battery of the present invention can operate normally in high and low temperature environments, and can also undergo environmental transitions from low to high temperature, that is, it has good electrochemical performance and safety performance over a wide temperature range from low to high temperature.

[0142] The high-energy-density lithium battery proposed in this invention has the following advantages:

[0143] (1) The lithium battery of the present invention can construct a high energy density battery material system by combining a positive electrode structure with a wide potential electrochemical window and a lithium-containing negative electrode structure, that is, by using high specific energy positive electrode material and high capacity lithium-containing negative electrode material in synergy.

[0144] The lithium battery of this invention uses a high-energy-density cathode material, which has the ability to charge and discharge over a wide voltage range. While increasing the charge and discharge voltage range of a material is a common method to improve energy density, material performance generally deteriorates rapidly when extending the charging and discharging potential. For example, lithium cobalt oxide cathodes, when discharged to 1.0V under extended potentials, exhibit irreversible structural degradation, meaning they cannot be charged and discharged again. To achieve a wider voltage range for the cathode material, this invention employs a high-energy-density lithium-containing anode material, increasing the active lithium content per unit area to over 0.26 mg / cm². 2 This is achieved by controlling the thickness of the lithium-containing anode to be between 5-160 μm.

[0145] The high specific energy cathode material Li in this invention x M y O z S m F n Achieving reversible charge-discharge over a wider voltage range effectively improves practically valuable energy density, specifically by addressing the synergistic effect between the lithium-containing anode and cathode materials. Unlike commercially available intercalated cathodes where the initial charge capacity is always greater than the discharge capacity, the cathode material of this invention possesses a monoclinic / trigonal composite layered structure with strong crystal flexibility and additional lithium storage sites. This means that the total amount of lithium inserted during the first cycle of charge-discharge over a wide potential range is greater than the total amount of lithium extracted, which is completely contrary to existing understanding. This is because after lithium ions completely occupy the octahedral sites of this cathode structure, they can continue to enter the tetrahedral sites. Due to the good flexibility of the structure, it exhibits good reversibility while increasing the material capacity. Although the special structural characteristics of the cathode material increase the discharge capacity, i.e., increase the energy density, traditional anodes cannot be matched for complete charge-discharge, preventing the additional capacity from being utilized. Therefore, additional lithium supplementation is required, and the amount of lithium supplemented in this invention is much greater than that supplemented by typical pre-lithiation processes. Common commercial batteries employ negative electrode pre-lithiation by adding a portion of active lithium to the negative electrode in advance to compensate for efficiency losses during the first cycle and capacity decay during long-term cycling. However, there is an upper limit to the amount of lithium added; the required lithium addition amount is 0.15 mg / cm³. 2When the upper limit is exceeded, i.e., the active lithium content in the negative electrode is too high, it will cause irreversible structural changes and collapse of the positive electrode structure when it stores excessive lithium, making the battery unable to perform stable and reversible charge and discharge. On the other hand, it will lead to further deterioration of the negative electrode material and electrode structure, such as the huge volume change of silicon-based negative electrodes, and will also lead to lithium plating during charge and discharge, posing a safety hazard to the battery. In contrast, the present invention sets a lower limit for the amount of lithium replenished to the negative electrode. When the positive and negative electrodes in the present invention are matched to form a material system, the lithium-containing negative electrode must have a sufficient amount of lithium replenishment to fully utilize the energy density of the system, thereby forming a reverse asymmetric charge and discharge mode. At the same time, it can provide compensation for the loss of active lithium in subsequent cycles and extend the cycle performance of the cell system.

[0146] As mentioned earlier, in high-energy-density battery systems such as lithium-sulfur batteries and lithium-air batteries, due to the electronic insulation and electrochemical characteristics of the active material on the positive electrode side, when the mass ratio of the active material reaches more than 80%, there is too little material for electronic conduction, making it impossible to form an electronic conduction network. This results in the battery being unable to charge and discharge due to excessive polarization. The high-load capacity positive electrode process provided by this invention requires a positive electrode material surface loading of ≥20 mg / cm³. 2 The active material in the positive electrode structure accounts for ≥92% by mass, and normal charge and discharge can still be performed under these conditions. This is partly because the positive electrode material synthesized in this invention has certain electronic conductivity characteristics. The positive electrode material of this application has electronic conductivity, which makes it possible for the active material in the positive electrode to account for more than 92% by mass and for high areal loading. On the other hand, the positive electrode structure of this invention also contains materials with an electronic conductivity of 10. 2 Conductive carbon with high electronic conductivity (S / cm or higher) is used in this invention. The cathode structure of this invention forms a thick electrode system. Thick electrodes, due to their high tortuosity and long ion diffusion paths, lead to a significant increase in battery polarization, preventing normal charge / discharge or causing a substantial degradation in battery performance. This invention utilizes conductive carbon, preferably carbon nanotubes, with high conductivity, thereby constructing a good electronic conductivity network. Using high-conductivity carbon nanotubes reduces the total amount of conductive carbon black used and increases the proportion of active material in the electrode. Therefore, the improved system of this invention, achieved through improvements in the cathode structure, ensures an active material mass ratio ≥92%, thus guaranteeing a high energy density battery and achieving ≥20 mg / cm². 2 The preparation of a high areal loading cathode ensures excellent electrochemical performance of the cathode electrode.

[0147] This invention employs a trace electrolyte addition technique. Typically, commercially available batteries add more than 2.5 g / Ah of electrolyte, while in this invention, the electrolyte and / or electrolyte mass to battery capacity ratio is 0.5-2.0 g / Ah. By constructing the material systems in the positive and negative electrode structures and limiting related process parameters, the addition of trace electrolyte can meet the high energy density and charge / discharge requirements of lithium batteries. The materials used include three types of electrolyte systems: liquid electrolyte, solid electrolyte, and solid-liquid hybrid electrolyte.

[0148] Therefore, based on the construction of a high-energy-density battery material system, this invention achieves an ultra-high energy-density lithium battery through improvements in cell technology, far exceeding the energy density of currently commercially available lithium batteries. This enables the battery cells to be used in electric aircraft or long-range electric vehicles. The lithium battery cells of this invention have a mass energy density of 500-1300 Wh / kg and a volumetric energy density of 900-2500 Wh / L. Furthermore, the mass energy density can be further increased to over 600 Wh / kg, and even further, to over 700 Wh / kg. Based on the above material combination and the limitations of various battery parameters, this battery can be cycled at least 3 times, and the battery system can be cycled up to 1000 times, achieving highly reversible charge-discharge of a high-energy-density battery.

[0149] (2) In the battery system of the present invention, under the above-mentioned charge / discharge cutoff voltage, the content of active lithium in the negative electrode at the end of the first discharge cycle is reduced by more than 10% compared with the original negative electrode. For lithium-ion batteries, during charging, Li + Lithium is extracted from the positive electrode, inserted into the negative electrode via the electrolyte, and the negative electrode is in a lithium-rich state; the process is reversed during discharge. This invention, by limiting the charge and discharge cutoff voltage of the cell system, ensures that active lithium in the lithium-containing negative electrode forms Li during the first discharge cycle. + Afterwards, it exits and enters the positive electrode via the electrolyte. During the cell's discharge process, not only does the Li enter the negative electrode during charging, but it also... +The lithium-containing anode material can return to the cathode material, and some of the active lithium in the lithium-containing anode can also enter the cathode. After the first discharge cycle of the battery system of this invention, the lithium content in the anode material decreases, while the lithium content in the cathode material is higher than the initial state. Therefore, the cell of this invention, when the cathode material is fully charged and reaches its effective capacity, will have a coulombic efficiency greater than 110% in the first cycle, which is not achievable in existing battery systems. This is because the active lithium content in the lithium-containing anode plays a role, matching the expanded lithium content of the cathode material, and synergistically achieving an increase in energy density at the material level. The lithium battery cell of this invention forms an asymmetric charge-discharge cycle, mitigating the volume change effect in the first cycle, and realizing the reversibility of the cathode material structure in subsequent cycles, providing support for subsequent charge-discharge cycles. This effectively solves the structural irreversibility problem caused by the cathode material in existing battery systems under wide-potential charge-discharge conditions, thereby ensuring the charge-discharge cycle performance of the battery system in a much wider voltage range than existing technologies, effectively improving the cycle stability of the battery system, and successfully realizing a commercially viable high-energy-density battery cell.

[0150] (3) The present invention incorporates modified materials into the positive electrode material, including oxides, fluorides, sulfides, polymers, ionic conductors, weak acids and other materials, which are the structure and components of the stable interface during battery charge and discharge cycles. Under the synergistic effect of electrolyte binder and conductive carbon, the composite positive electrode undergoes volume change and interface evolution after charge and discharge. The distribution of binder and conductive carbon changes, thus making them more closely connected with the positive electrode material. A conductive network with higher electronic and ionic conductivity is constructed between the original positive electrode particles and the mixed materials. A more stable passivation interface is formed on the surface of the composite positive electrode material particles, which greatly increases the rate performance, cycle performance and safety performance of the battery material.

[0151] (4) The preferred cathode material of the present invention is Li x M y O z S m F nWhere 1≤x≤2, 0<y≤1, 2≤z≤6, 0<m≤1 / 2, 0<n≤1, and M is two or more of Ni, Co, Mn, Al, Cu, Fe, Mg, Ti, Zn, Cr, V, Zr, and Nb. The combination of a cathode material with the above-mentioned specific structure and a lithium-containing anode system can fully leverage the advantages of high capacity. Furthermore, during charge-discharge cycling over a wide potential window, it can receive active lithium from the anode, thus minimizing irreversible structural changes and ensuring the stability of the cathode material structure. This enables asymmetric charge-discharge formation in the first cycle of the cathode, significantly improving the battery's energy density. In subsequent charge-discharge cycles, the cathode material can continuously compensate for the loss of active lithium, extending the cycle performance of the cell system. In addition, the cathode material with the above structure possesses specific cathode bulk phase and surface structure, ensuring better structural stability over a wide potential range, thereby achieving reversible charge-discharge behavior. Meanwhile, the special structure of the cathode surface in this invention enhances the dispersion of conductive carbon during slurry mixing, reducing the proportion of conductive carbon used and increasing energy density. Furthermore, the cathode of this invention also considers compatibility with the electrolyte under high voltage. Due to the post-processing in the synthesis of the cathode material, it interacts with the electrolyte during charging and discharging, forming a stable passivation interface in situ on the electrode surface, further improving cycle performance. Simultaneously, this passivation interface can suppress oxygen production in the cathode material, mitigating the catalytic decomposition of the electrolyte under high voltage and reducing gas production. Therefore, the cathode of this invention achieves better cycle performance and safety while increasing energy density.

[0152] For positive electrode structures, when using liquid electrolytes, insufficient electrolyte injection significantly reduces electrode wettability, especially for thick electrodes where complete wetting may be impossible. This invention addresses this by increasing the electrode's compaction density, thereby reducing porosity and consequently decreasing the required electrolyte volume. To further reduce the porosity of the positive electrode sheet and ensure improved conductivity and ion mobility even with low electrolyte usage, the compaction density of the positive electrode sheet is maintained at >2.2 g / cm³. 3 On the other hand, the cathode material synthesized in this invention, possessing the aforementioned structural formula, exhibits a unique sulfidated and fluorinated surface structure. This structure allows it to chemically bond with salt or solvent molecules in the electrolyte. When the cathode is assembled into a battery, contact with the electrolyte significantly increases the wettability and wetting rate of the electrolyte, creating a capillary effect in electrode electrolyte injection and reducing the amount of electrolyte injected. Simultaneously, the stable interface of the cathode reduces interfacial side reactions during battery cycling, decreasing electrolyte consumption and improving electrolyte retention. This invention employs a trace electrolyte combined with the aforementioned high-density cathode structure, thereby ensuring the battery system can perform normal charge-discharge cycles and significantly improving the energy density of the battery system.

[0153] Furthermore, after the positive electrode sheet of the present invention has the above-mentioned compaction density, the conductive carbon in the positive electrode is in closer contact with the active material, thereby effectively reducing electrode impedance and battery polarization.

[0154] (5) The lithium battery of the present invention reduces the mass ratio of inactive materials in the cell through an ultra-lightweight current collector without compromising the electrochemical performance of the cell. More preferably, a flexible composite current collector is used, which combines the advantages of reduced mass and improved electrochemical performance, making it the optimal material for high-energy-density batteries. The flexible composite current collector, through single-layer or multi-layer composite construction, significantly reduces the current collector mass and effectively facilitates current transfer during battery charging and discharging. Because the composite current collector uses an intermediate polymer layer, the presence of the polymer can isolate electron transfer between the positive and negative electrodes in the event of mechanical puncture, significantly improving the safety of the lithium battery cell.

[0155] (6) The passivation layer interface between the negative electrode material and the negative electrode current collector in the lithium battery of the present invention has multiple functions. On the one hand, the lithium-loving passivation layer interface can homogenize lithium ion deposition, stabilize the interface composition and structure, and more effectively suppress lithium dendrite growth, ensuring the safety performance of the battery. On the other hand, the passivation layer is used to match the stability of the negative electrode material and the current collector under a wide voltage range, because metals in the current collector, such as copper, are more likely to dissolve at low potentials. Due to the protection of the passivation layer interface in the present invention, metal dissolution can be suppressed.

[0156] (7) This invention employs an electrolyte with a wide electrochemical window that matches the wide potential positive electrode charge / discharge cutoff voltage. By using a thinner, less mass-proportion solid electrolyte, the overall energy density of the cell can be significantly improved. A composite solid electrolyte composed of polyester polymer electrolyte and inorganic compound is preferred, as it can balance excellent ionic conductivity, mechanical properties, and improved interfacial contact. For the liquid electrolyte, a high-voltage resistant electrolyte is used to improve the interfacial stability of the positive electrode material at high potentials. At the same time, the electrolyte injection volume is less than that of traditional lithium-ion batteries. The electrolyte injection volume of this invention can be as low as 1.8 g / Ah, which can meet the requirements and further improve the energy density of the lithium battery cell.

[0157] (8) In the battery system of the present invention, the separator is a separator with symmetrical or asymmetrical interface coatings on both sides. The interface layer on the positive electrode side is used to alleviate the stability of the positive electrode under high voltage, and the interface on the negative electrode side is used to stabilize the negative electrode interface. At the same time, the interface coating of the separator can chemically bond with the negative electrode, and the close contact interface can homogenize the lithium ion deposition solvent and effectively prevent the growth of lithium dendrites. In addition, the coating layer on the separator can also significantly improve the thermal stability and increase the wettability of the electrolyte.

[0158] (9) The present invention uses lightweight packaging materials to reduce the mass of inactive substances while ensuring the sealing performance of the packaging.

[0159] (10) The lithium battery of the present invention can not only significantly improve energy density, but also have good electrochemical performance and safety performance over a wide temperature range, thereby meeting the requirements of electric vehicles and electric aircraft operating environments with large temperature variations, including large fluctuations between low temperature and high temperature environments.

[0160] The high-energy-density lithium battery described in this invention possesses ultra-high gravimetric and volumetric energy densities, making it suitable for use in lithium battery packs or modules. When applied to end products, it also exhibits high energy density, and its combined application in high-energy-density energy consumption scenarios can meet the needs of electric aircraft.

[0161] The invented lithium battery breaks through the bottlenecks of existing commercial lithium batteries in terms of gravimetric and volumetric energy density, significantly improving the energy density of lithium batteries, especially cell batteries, thereby meeting the application requirements for high energy density. The battery system of this invention has superior performance.

[0162] To better illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are for a better understanding of the present invention and are not limited to the described preferred embodiments, nor do they constitute a limitation on the content and scope of protection of the present invention. Any product identical or similar to the present invention derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art falls within the protection scope of the present invention.

[0163] The Ni used in the following examples and comparative examples 0.12 Co 0.12 Mn 0.76 The positive electrode materials, such as CO3, lithium cobalt oxide (LCO), and lithium nickel cobalt manganese oxide (NCM), were purchased from Zhongwei New Materials Co., Ltd. The electrolyte and electrolyte additives were from Suzhou Duoduo Chemical Technology Co., Ltd. The solid electrolyte, polymer electrolyte, and other related materials were from Beijing Weilan New Energy Technology Co., Ltd. The negative electrode lithium metal was from Tianjin Zhongneng Lithium Industry Co., Ltd. Unless otherwise specified, the remaining modified materials were from Beijing Innocare Technology Co., Ltd.

[0164] For any experimental steps or conditions not specified in the embodiments, the procedures or conditions described in the literature in this field can be followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available conventional reagent products.

[0165] Example

[0166] This embodiment proposes a lithium-rich oxide cathode material, Li, for high-energy-density lithium batteries. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2, denoted as lithium-rich oxide A-1, is Li. x M y O z S m F n In the given information, M represents Ni, Co, and Mn, x = 1.2, y = 0.8, z = 2, m = 0, and n = 0.

[0167] An example of a method for synthesizing lithium-rich oxide A-1 is as follows:

[0168] First, the transition metal oxide precursor Ni 0.12 Co 0.12 Mn 0.76 CO3 and lithium carbonate (lithium source) were mixed uniformly at a molar ratio of 1:1.6. The mixture was then placed in a muffle furnace and heated to 600°C. Under an oxygen atmosphere, the mixture was calcined at 600°C for 5 hours, then heated to 850°C and held for 18 hours. Finally, the temperature was lowered to 500°C and annealed for 1 hour to obtain the lithium-rich oxide cathode material 0.5Li2MnO3-0.5LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2, i.e., Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 (lithium-rich oxide A-1).

[0169] This embodiment also proposes a lithium-rich oxide cathode material, Li, for high-energy-density lithium batteries. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2S 0.01 F 0.02 This is denoted as lithium-rich oxide A-2, i.e., Li. x M y O z S m F n In the equation, M represents Ni, Co, and Mn, x = 1.2, y = 0.8, z = 2, m = 0.01, and n = 0.02.

[0170] An example of a method for synthesizing lithium-rich oxide A-2 is as follows:

[0171] First, the transition metal oxide precursor Ni 0.12 Co 0.12 Mn 0.76CO3 and lithium carbonate (lithium source) were mixed uniformly at a molar ratio of 1:1.6. The mixture was then placed in a muffle furnace and heated to 600°C. Under an oxygen atmosphere, the mixture was calcined at 600°C for 5 hours, then heated to 850°C and held for 18 hours. Finally, the temperature was lowered to 500°C and annealed for 1 hour to obtain the lithium-rich oxide cathode material 0.5Li2MnO3-0.5LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2, i.e., Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 is then sulfided in a tubular furnace filled with inert gas and elemental sulfur, followed by fluorination in a tubular furnace filled with inert gas and ammonium fluoride to obtain the cathode material Li. 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2S 0.01 F 0.02 (Lithium-rich oxide A-2).

[0172] Performance characterization of cathode materials:

[0173] Step 1. Preparation of button cell electrode sheets

[0174] This step uses a conventional laboratory coin cell preparation method: 100 mg of polyvinylidene fluoride (PVDF) is dissolved in 3 ml of N-methylpyrrolidone (NMP) and stirred to form a homogeneous solution. 800 mg of lithium-rich oxide A-1 and 100 mg of superconducting carbon black conductive agent, and 800 mg of lithium-rich oxide A-2 and 100 mg of superconducting carbon black conductive agent are added sequentially to two portions of the above solution, respectively. After stirring for 8 hours, two electrode slurries are prepared. The two electrode slurries are coated onto aluminum foil and dried at 60 °C to obtain positive electrode sheets A1 and A2, respectively.

[0175] Step 2. Button cell battery assembly

[0176] The positive electrode obtained in step 1 was punched into Φ12mm circular electrodes and dried in a vacuum drying oven at 120℃ for 12 hours. Subsequently, in a vacuum glove box, CR2016 coin cells were assembled using lithium metal sheets as negative electrodes, the prepared A1 and A2 as positive electrodes respectively, conventional commercial lithium-ion electrolytes, and conventional commercial Celgard PP / PE separators.

[0177] Step 3. Electrochemical performance testing:

[0178] The coin cell was charged to 4.8V at a current density of 25mA / g, and then discharged to 2.5V for charge-discharge cycling. The charge-discharge curves are shown below. Figure 1 As shown in Figure a, the cycle performance curve is as follows: Figure 1 As shown in b.

[0179] like Figure 1 As shown, the lithium-rich oxide A-1 material exhibits a first-cycle charge specific capacity of 325.3 mAh / g, a discharge specific capacity of 274.2 mAh / g, and an initial coulombic efficiency of 84.29%. After 100 charge-discharge cycles, the material's discharge specific capacity is 240.67 mAh / g, with a capacity retention of 87.77%. The lithium-rich oxide A-2 material exhibits a first-cycle charge specific capacity of 339.1 mAh / g, a discharge specific capacity of 301.2 mAh / g, and an initial coulombic efficiency of 88.82%. After 100 charge-discharge cycles, the material's discharge specific capacity is 277.25 mAh / g, with a capacity retention of 92.05%. Based on the electrochemical performance test results, this material demonstrates good cycle performance and specific capacity.

[0180] Example 1

[0181] A lithium battery was prepared using synthesized lithium-rich oxide A-2 as the positive electrode material. The preparation process is as follows:

[0182] Step 1. Preparation of button cell electrode sheets

[0183] This step employs a conventional laboratory coin cell preparation method: 100 mg of polyvinylidene fluoride (PVDF) is dissolved in 3 ml of N-methylpyrrolidone (NMP) and stirred to form a homogeneous solution. Then, 800 mg of lithium-rich oxide A-2 and 100 mg of superconducting carbon black are added sequentially, and the mixture is stirred for 8 hours to prepare an electrode slurry. The electrode slurry is coated onto aluminum foil and dried at 60°C to obtain the positive electrode sheet. The positive electrode active material accounts for 93%, and the areal loading is 25 mg / cm³. 2 .

[0184] Step 2. Button cell battery assembly

[0185] The positive electrode sheet obtained in step 1 was punched into multiple Φ12mm circular electrode sheets and dried in a vacuum drying oven at 120℃ for 12 hours. Subsequently, in a vacuum glove box, using a lithium metal sheet as the negative electrode, the prepared lithium-rich oxide A-2 electrode as the positive electrode, a conventional commercial lithium-ion electrolyte, and a conventional commercial Celgard PP / PE separator, three sets of CR2016 coin cells were assembled.

[0186] Step 3. Electrochemical performance testing:

[0187] Three sets of coin cells were charged to 4.8V at a current density of 25mA / g, and then discharged to 1.0V, 1.25V and 1.5V respectively for electrochemical cycling.

[0188] In this embodiment, lithium-rich oxide A-2 is used as the cathode material to construct a battery system. Its charge-discharge range is expanded by discharging to lower voltages to embed more Li ions into the cathode material lattice, thereby improving its discharge specific capacity. The electrochemical performance is obtained by comparing different discharge cutoff voltages. The charge-discharge and cycle performance curves are shown below. Figure 2 As shown in Table 1, the electrochemical performance data are presented. The discharge mass energy density is the energy density of the material (obtained from assembling a lithium-ion half-cell).

[0189]

[0190] Table 1

[0191] like Figure 2 As shown in Table 1, when the three identical battery systems were discharged to 1.0V, 1.25V, and 1.5V respectively, the initial discharge specific capacities were 442.8mAh / g, 409mAh / g, and 371.3mAh / g, respectively. Figure 2 As shown in curve (a), compared with the discharge voltage of each battery system at 2.5V, the discharge specific capacity increased by 153.8 mAh / g, 120 mAh / g, and 82.3 mAh / g, respectively. The initial coulombic efficiencies at 1.0V, 1.25V, and 1.5V were 140.57%, 129.84%, and 117.87%, respectively, all greater than 110%, while the active lithium in the negative electrode decreased by 44%, 30%, and 18%, respectively.

[0192] The reduction in active lithium content in the negative electrode can be determined using any of the following methods: 1) By disassembling parallel samples, taking the original negative electrode as a blank control, and using it simultaneously with the negative electrode from the first discharge cycle as the positive electrode, reassemble the lithium metal negative electrode into a coin cell, and test the available capacity of the positive electrode; 2) By measuring the change in lithium content before and after the first charge-discharge cycle using inductively coupled plasma atomic emission spectrometry. The data in this embodiment were obtained using method 1).

[0193] When the three identical battery systems were discharged to 1.0V, 1.25V, and 1.5V respectively, the initial discharge specific energies were 1288.9Wh / kg, 1240.5Wh / kg, and 1193.2Wh / kg. Regarding cycle performance, after 10 cycles, the remaining specific energy at the 1.0V discharge cutoff voltage was 997.6Wh / kg, the remaining specific energy at the 1.5V discharge cutoff voltage was 1025.3Wh / kg, and the remaining specific energy at the 1.25V discharge cutoff voltage was 990.5Wh / kg. Figure 2(b) It can be seen that when the discharge cutoff voltage is 1.0V, its initial discharge specific energy is significantly higher than the other two discharge cutoff voltages. After 10 cycles, its discharge specific energy is lower than 1.5V but higher than 1.25V. Therefore, in terms of capacity retention, discharging to a lower voltage of 1.0V is actually better than 1.25V. This fully demonstrates that a lower discharge cutoff voltage does not necessarily mean worse cycle performance. Rather, by constructing a positive electrode material and a lithium negative electrode battery system, a battery system with higher specific energy and better cycle performance can be obtained. Therefore, from the perspective of energy density, a 1.0V cutoff voltage can achieve a higher discharge specific energy than 1.5V and 1.25V.

[0194] The above-mentioned positive electrode material was fabricated into a large-area positive electrode sheet using the same process as that used in coin cells. Then, the above-mentioned positive electrode sheet and the lithium metal negative electrode sheet (30μm, with an active lithium content of 1.602 mg / cm²) were combined. 2 Battery cells were obtained by stacking separators of corresponding sizes in a Z-shape on a stacking machine. The cells then underwent tab welding, encapsulation, electrolyte injection, formation, secondary sealing, and capacity testing. The electrolyte injection rate for each cell was 1.5 g / Ah, ultimately yielding three sets of soft-pack full batteries. Based on the mass of the positive electrode active material, the cell capacity was 9.2 Ah. The three sets of batteries were charged to 4.8V at 1A, and then discharged to 1.0V, 1.25V, and 1.5V respectively. Calculations show that the obtained pouch battery has a mass energy density of 690.01 Wh / kg and a volumetric energy density of 1581.02 Wh / L at a discharge cutoff voltage of 1.5V; a mass energy density of 716.49 Wh / kg and a volumetric energy density of 1678.61 Wh / L at a discharge cutoff voltage of 1.25V; and a mass energy density of 760.45 Wh / kg and a volumetric energy density of 1731.82 Wh / L at a discharge cutoff voltage of 1.0V.

[0195] Example 2

[0196] In this embodiment, lithium-rich oxide A-2 is used as the main material of the cathode, and then modified materials are added to form a composite cathode material. The modified materials are lithium cobalt oxide (LiCoO2, LCO) and single-crystal nickel cobalt manganese oxide (LiNiO2). 0.6 Co 0.2 Mn 0.2LCO (NCM622), titanium fluoride (TiF3), sodium sulfide (Na2S), and zirconium oxide (ZrO2) were used as modifying materials. LCO and NCM622 were each added at 10% of the mass of the composite cathode material, while TiF3, Na2S, and ZrO2 were each added at 5% of the mass of the composite cathode material. The lithium-rich oxide A-2 and the modifying materials were combined using one of the following methods: physical manual grinding, mechanical ball milling, liquid-phase mixing, magnetron sputtering atomic layer deposition, physical / chemical vapor deposition, or electrochemical deposition to form a uniform composite material. In this embodiment, mechanical ball milling was used.

[0197] The prepared composite material was assembled into a coin cell and tested.

[0198] Steps 1 and 2 are the same as the preparation process in Example 1, except for the cathode material. The coating thickness of the lithium-rich oxide A-2+LCO composite cathode material and the lithium-rich oxide A-2+NCM622 composite cathode material is 400 μm; the coating thickness of the lithium-rich oxide A-2+TiF3 composite cathode material, the lithium-rich oxide A-2+Na2S composite cathode material, and the lithium-rich oxide A-2+ZrO2 composite cathode material is 280 μm. Five sets of batteries were obtained. Two sets of coin cells using pure lithium-rich oxide A-2 as the cathode material were then prepared using the same process as in Steps 1 and 2 of Example 1, with coating thicknesses of 280 μm and 400 μm, respectively. The active material content of the A-2+NCM622 or A-2+LCO cathode is 96.2%, and the active material content of the A-2, A-2+TiF3, A-2+Na2S, and A-2+ZrO2 cathodes is 94.2%. The areal loading of the 400μm thick electrode is 28.06 mg / cm². 2 The surface loading of the 280μm thick electrode is 20.32mg / cm². 2 .

[0199] Step 3. Electrochemical performance testing

[0200] Seven battery packs were charged to 4.8V at a current density of 25mA / g, then discharged to 2V, and subjected to charge-discharge cycles at a current density of 50mA / g; the cycle performance curves are shown below. Figure 3 As shown in Table 2, the electrochemical performance data are presented. The discharge mass energy density is the energy density of the material (obtained from assembling a lithium-ion half-cell).

[0201]

[0202] Table 2

[0203] like Figure 3As shown in a and Table 2, when lithium-rich oxide A-2 (400μm), lithium-rich oxide A-2+LCO, and lithium-rich oxide A-2+NCM622 are used as cathode materials in the battery system, the initial discharge specific capacity of lithium-rich oxide A-2 is 289.6 mAh / g and the mass energy density is 1062.35 Wh / kg when the number of cycles is less than 30; the initial discharge specific capacity of lithium-rich oxide A-2+LCO composite cathode material is 290.1 ​​mAh / g and the mass energy density is 1066.18 Wh / kg; and the initial discharge specific capacity of lithium-rich oxide A-2+NCM622 composite cathode material is 295.8 mAh / g and the mass energy density is 1068.79 Wh / kg. The discharge specific capacity and mass energy density of the lithium-rich oxide A-2+NCM622 composite cathode material are significantly higher than those of the other two cathode materials.

[0204] When the number of cycles exceeded 30, the specific capacity of all three composite cathode materials decreased significantly, but the discharge specific capacity of the lithium-rich oxide A-2+NCM622 composite cathode material remained higher than that of the other two cathode materials. After 50 cycles, the capacity retention rate of lithium-rich oxide A-2+NCM622 was 72.26%, and that of the lithium-rich oxide A-2+LCO composite cathode material was 74.98%, both higher than the capacity retention rate of 71.06% for lithium-rich oxide A-2.

[0205] The above analysis shows that the discharge specific capacity and cycle performance of the two composite cathode materials after the addition of modified materials are better than those of pure lithium-rich oxide A-2, and the comprehensive performance of the lithium-rich oxide A-2+NCM622 composite cathode material is the best.

[0206] Figure 3b shows the cycle performance of lithium-rich oxide A-2 (280μm), lithium-rich oxide A-2+ZrO2, lithium-rich oxide A-2+TiF3, and lithium-rich oxide A-2+Na2S as the cathode materials of the battery system. The lithium-rich oxide A-2 cathode material exhibits an initial discharge specific capacity of 284.7 mAh / g and a mass energy density of 1044.25 Wh / kg, with a capacity retention of 87.74% after 50 cycles. The lithium-rich oxide A-2+ZrO2 composite cathode material exhibits an initial discharge specific capacity of 294.9 mAh / g and a mass energy density of 1065.32 Wh / kg, with a capacity retention of 91.77% after 50 cycles. The lithium-rich oxide A-2+TiF3 composite cathode material exhibits an initial discharge specific capacity of 281.8 mAh / g and a mass energy density of 1036.73 Wh / kg, with a capacity retention of 93.97% after 50 cycles. The lithium-rich oxide A-2+Na2S composite cathode material exhibits an initial discharge specific capacity of 276.7 mAh / g and a mass energy density of 998.69 Wh / kg, with a capacity retention of 94.52% after 50 cycles.

[0207] Therefore, the discharge specific capacity of lithium-rich oxide A-2+ZrO2 is significantly higher than that of the other three cathode materials, while the cycling performance of lithium-rich oxide A-2+Na2S is significantly better than the other three cathode materials, maintaining a high capacity retention rate after 50 charge-discharge cycles. The discharge specific capacity and capacity retention rate after 50 cycles of lithium-rich oxide A-2+TiF3 fall between the other two composite cathode materials. Thus, all three composite cathode materials exhibit high discharge specific capacity and excellent cycling performance, but the composite cathode material with the addition of modified TiF3 demonstrates the best overall performance. Figure 3 As can be seen from b, the lithium-rich oxide A-2 (280μm) has an excellent initial discharge capacity, but its cycle performance is inferior to that of composite cathode materials. After 20 charge-discharge cycles, its discharge specific capacity is significantly lower than that of other composite cathode materials.

[0208] A pouch cell was prepared using the full-cell fabrication process described in Example 1. The cells were charged to 4.8V at a current of 1A and then discharged to 2.0V. The pouch cell with A-2+NCM622 as the positive electrode active material had an energy density of 630.58Wh / kg and a volumetric energy density of 1396.21Wh / L; the pouch cell with A-2+ZrO2 as the positive electrode active material had an energy density of 617.89Wh / kg and a volumetric energy density of 1376.35Wh / L; and the pouch cell with A-2+TiF3 as the positive electrode active material had an energy density of 615.62Wh / kg and a volumetric energy density of 1373.37Wh / L.

[0209] Example 3

[0210] The lithium-rich oxide A-2+TiF3 composite material from Example 2 was used as the positive electrode active material, and high-capacity metallic lithium was used as the negative electrode. To suppress lithium dendrite growth during cycling, the surface of the negative electrode current collector was pretreated to have a passivation layer, and then 40 μm of metallic lithium was loaded onto it. The mass of active lithium per unit area on a single-sided loading surface was 2.14 mg / cm². 2 .

[0211] Step 1 is the same as the preparation process in Example 1, wherein the coating thickness of the positive electrode active material is 500 μm.

[0212] Step 2. Preparation of negative electrode sheet for coin cell battery

[0213] First, a 10 nm lithium-affinity passivation layer was prepared on the surface of a 6 μm copper current collector by magnetron sputtering. In this embodiment, silicon, silver, and aluminum deposition layers were selected to form the passivation layer. Subsequently, 40 μm of metallic lithium was loaded onto the surface of the current collector by methods such as cold pressing, fused deposition, and electroplating under inert atmosphere protection or in a super clean room.

[0214] Step 3. Button cell assembly

[0215] The obtained positive electrode sheet was punched into a Φ12mm circular sheet, and the negative electrode sheet was punched into a Φ14mm circular sheet under an inert atmosphere. The positive electrode sheet was dried in a vacuum drying oven at 120℃ for 12 hours. Subsequently, in a vacuum glove box, the prepared positive and negative electrodes, electrolyte (conventional commercial lithium-ion electrolyte), and separator (conventional commercial Celgard PP / PE separator) were assembled into a CR2016 coin cell.

[0216] Step 4. Charge the battery to 4.8V at a current density of 25mA / g, then discharge it to 2V for the first charge-discharge cycle, and perform charge-discharge cycles at a current density of 50mA / g; the cycle performance curve is shown below. Figure 4 As shown in Table 3, the electrochemical performance data are as follows.

[0217]

[0218] Table 3

[0219] like Figure 4As shown in Table 3, when a 10nm silicon, aluminum, or silver passivation layer is formed between the negative electrode current collector and the negative electrode, even if the positive electrode active material coating thickness is 500μm, the coin cell formed by the passivated negative electrode and the relatively thick positive electrode matching current collector can still undergo normal charge-discharge cycles. When the negative electrode current collector passivation layer is silicon, aluminum, or silver, the initial discharge specific capacity of the battery is 273.3mAh / g, 280.2mAh / g, and 299.1mAh / g, respectively, with corresponding initial coulombic efficiencies of 90.77%, 92.29%, and 99.83%, respectively, all exceeding 90%. In contrast, the battery with a conventional current collector without a passivation layer has an initial discharge specific capacity of only 261.3mAh / g and an initial coulombic efficiency of only 88.67%, indicating that the battery with no passivation layer on the negative electrode has a low discharge specific capacity and the worst electrochemical performance. Among them, the coin cell corresponding to the silver passivation layer exhibits the highest first-cycle discharge specific capacity and the highest coulombic efficiency, maintaining a high discharge specific capacity of 289.1 mAh / g in the second cycle. This is because the silver passivation layer, while preventing lithium dendrite growth, also reduces the contact resistance between the negative electrode current collector and the active material, thereby improving electrode conductivity. Using the full-cell fabrication process of Example 1, the battery was charged to 4.8V at a current of 1A and then discharged to 2.0V. The pouch cell with a silver passivation layer current collector at the negative electrode has an energy density of 621.46 Wh / kg and a volumetric energy density of 1383.73 Wh / L.

[0220] Example 4

[0221] This embodiment uses the lithium-rich oxide A-2+TiF3 composite material from Example 2 as the positive electrode active material and high-specific-capacity composite lithium metal as the negative electrode material. The aim is to further reduce the mass ratio of auxiliary materials (mainly current collectors), increase the mass ratio of active materials, and fully exploit the battery energy density.

[0222] Step 1. Preparation of the positive electrode sheet

[0223] Positive electrode sheets were prepared using conventional industrial coating techniques, including processes such as binder preparation, slurry preparation, coating, baking, rolling, slitting, and die-cutting. The prepared sheets had an active material content of 97.5% and an areal loading of 34.86 mg / cm³. 2 The positive electrode sheet. The positive current collector is a 9μm ultrathin aluminum foil. The positive electrode sheet is cut to a size of 73×60mm using a die-cutting machine.

[0224] Step 2. Preparation of the negative electrode sheet

[0225] The negative electrode preparation process is the same as that in Example 3. The difference lies in the use of a flexible porous film current collector, which consists of a middle polymer layer and upper and lower copper layers. The copper layer is 1 μm thick, and the polymer materials are 10 μm thick PET, PP, and PE, respectively. The current collector is loaded with lithium metal on both sides. The negative electrode is cut to a size of 75 × 62 mm using a die-cutting machine.

[0226] Step 3. Assembly of the full battery

[0227] The positive and negative electrode sheets are stacked with a separator of corresponding size in a Z-shape on a stacking machine to obtain a battery cell. The cell then undergoes tab welding, encapsulation, electrolyte injection, formation, secondary sealing, and capacity testing to finally obtain a pouch battery. The electrolyte injection amount is within the conventional commercial range; in this embodiment, the injection amount is 2 g / Ah. Based on the positive electrode active material, the theoretical battery capacity is calculated to be 9 Ah.

[0228] Step 4. Charge the three battery banks to 4.8V at 1A, then discharge them to 2V; the charge / discharge curves are as follows. Figure 5 As shown in Table 4, the electrochemical performance data are as follows.

[0229]

[0230] Table 4

[0231] like Figure 5 As shown in Table 4, based on the test results, all pouch cells were able to fully utilize their capacity and achieve high energy densities, far exceeding those of existing commercial lithium-ion batteries. The use of different composite current collectors significantly impacted battery performance. The cell using a PP composite current collector exhibited the best electrochemical performance, with an initial discharge capacity of 8.72 Ah, a mass energy density of 632.3 Wh / kg, a volumetric energy density of 1098.5 Wh / L, and an initial coulombic efficiency of 95.40%. The cell using a PET composite current collector had an initial discharge capacity of 8.45 Ah, with mass and volumetric energy densities of 629.8 Wh / kg and 1021.5 Wh / L, respectively, but a lower initial coulombic efficiency of only 60.49%. The cell using a PE composite current collector had an initial discharge capacity of 8.69 Ah, with mass and volumetric energy densities of 630.6 Wh / kg and 1062.3 Wh / L, respectively, and an initial coulombic efficiency of 90.24%. Therefore, the use of PP and PE composite current collectors demonstrated excellent electrochemical performance. The full-cell battery with PET composite current collector has a very high charging capacity but a low discharge capacity and poor initial coulombic efficiency, resulting in the loss of some active lithium.

[0232] Compared to traditional aluminum or copper current collectors, composite current collectors have significant advantages in terms of mass, which can greatly reduce the mass ratio of the current collector in the whole battery and greatly promote the improvement of battery mass energy density and volumetric energy density.

[0233] Example 5

[0234] Using the positive and negative electrode structure system of Example 4 and the PP composite current collector as in Example 4, corresponding soft-pack lithium metal batteries were prepared according to the same process as in Example 4. The difference was that the separators were respectively used as follows: separator 1—LATP single-sided coating (coating thickness 50nm), separator 2—Al2O3 single-sided coating (coating thickness 200nm), and separator 3—uncoated separator. After optimizing the electrolyte injection amount for the coated separators, soft-pack full battery samples 5-1, 5-2, and 5-3 were obtained. The designed capacity of the soft-pack full battery was 2Ah, and the electrolyte injection amount was 2.0g / Ah. The three types of batteries were charged to 4.8V with a current of 200mA and then discharged to 2V; the charge-discharge curves are shown below. Figure 6 As shown in Table 5, the electrochemical performance data are as follows.

[0235]

[0236] Table 5

[0237] like Figure 6 As shown in Table 5, the electrochemical performance of the two batteries with different coated membranes is significantly improved compared to the uncoated batteries.

[0238] The mass energy densities of the pouch cells 5-1, 5-2, and 5-3 are 512.6 Wh / kg, 510.8 Wh / kg, and 501.5 Wh / kg, respectively, and their volumetric energy densities are 1024.8 Wh / L, 1012.5 Wh / L, and 1002.1 Wh / L, respectively. Their initial coulombic efficiencies are 98.65%, 98.58%, and 98.47%, respectively, and their capacity retention rates after 100 charge-discharge cycles are 85.5%, 82.3%, and 76.2%, respectively. It can be seen that compared with the uncoated separator, the mass energy density and volumetric energy density of the separator coated with LATP and Al2O3 are significantly improved, and the initial coulombic efficiency and capacity retention rate after 100 cycles are also improved to a certain extent. The pouch lithium metal battery with LATP single-sided coating achieves an initial coulombic efficiency of 98.65%, exhibiting the best electrochemical performance.

[0239] Example 6

[0240] This embodiment focuses on the impact of electrolyte on battery performance.

[0241] High-energy-density battery cells typically need to operate at high potentials, placing stringent demands on the stability and film-forming properties of the electrolyte. Adding appropriate additives to the electrolyte can help improve the electrochemical performance of the material. Using the lithium-rich oxide A-1 obtained in the aforementioned examples as the positive electrode active material, a corresponding coin cell was obtained using the coin cell electrode sheet and battery assembly technology of Example 1.

[0242] The difference lies in the electrolytes used: a standard commercial lithium-ion electrolyte, a standard commercial lithium-ion electrolyte with 0.01M vinylene carbonate (VC) added (denoted as electrolyte 1), and a standard commercial lithium-ion electrolyte with 0.01M lithium bis(trifluoromethanesulfonyl)imide added (denoted as electrolyte 2). The three sets of batteries were charged to 4.8V at 25mA and then discharged to 1V; the charge-discharge curves are shown below. Figure 7 As shown.

[0243] The test results show that the initial discharge behavior of the batteries obtained with the three different electrolytes remained almost unchanged, and the discharge specific capacity was very similar. After 10 cycles, the batteries obtained with electrolytes 1 and 2 showed higher discharge specific capacity compared to the electrolyte without additives, demonstrating an advantage. Specifically, the discharge specific capacity of the battery with electrolyte 2 was 9 mAh / g higher than that of electrolyte 1. These results indicate that adding additives to conventional electrolytes has almost no effect on specific energy. However, as the number of cycles increases, the battery without additives begins to fail, and its cycle performance declines. At 150 cycles, the conventional electrolyte cannot continue cycling, while the batteries with the two added electrolytes exhibit better cycle performance. The battery with electrolyte 2 showed a significantly slower degradation rate after 10 cycles. These results suggest that in the over-discharge cycling of lithium-rich batteries, adding a certain amount of additives to the electrolyte can improve the cycle stability of the battery system and enhance the matching performance between the electrolyte and the high-specific-energy positive and negative electrodes. Using the lithium metal full battery preparation process of Example 4, the pouch cell with electrolyte 2 has a mass energy density of 611.35 Wh / kg and a volumetric energy density of 1326.85 Wh / L.

[0244] Example 7

[0245] This embodiment takes into account the complex working environment of the battery. Depending on the region and time, the ambient temperature will vary significantly. Therefore, the focus is on discussing the working performance of the battery under different temperature conditions in actual applications.

[0246] A coin cell was fabricated using lithium-rich oxide A₂+TiF₃ as the composite positive electrode, lithium alloy as the negative electrode, and a conventional electrolyte with additives of 0.01 M vinylene carbonate and 0.01 M LiBF₄, along with a PP composite flexible current collector. The coin cell fabrication process was the same as described in Example 1. The fabricated coin cells were placed in a 60°C constant temperature chamber for 4 hours to allow their internal and external temperatures to equalize. They were then charged to 4.8 V at a current density of 25 mA / g, discharged to 2.0 V, and subsequently charged and discharged at a current density of 50 mA / g. The battery cycle curves are shown below. Figure 8 As shown.

[0247] Test results show that the battery can still perform normal charge-discharge cycles at 60℃. Due to the increased temperature, ion migration rate increases, battery activity increases, and the initial discharge capacity exceeds 360 mAh / g, with the material's gravimetric energy density approaching 1200 Wh / kg. With increasing charge-discharge cycles, the battery capacity decreases systematically without any significant drop. This indicates that the battery system can maintain excellent electrochemical performance over a wider temperature range.

[0248] In addition, a soft-pack battery assembled according to Example 4, using lithium-rich oxide A-2+TiF3 as the positive electrode, lithium alloy as the negative electrode, conventional electrolyte with additives of 0.01M vinylene carbonate and 0.01M LiBF4, and PP composite flexible current collector, achieved a mass energy density of 710Wh / kg and a volumetric energy density of 1600Wh / L in charge-discharge cycle tests at 60°C.

[0249] Example 8

[0250] This embodiment focuses on exploring the correlation between the battery's mass energy density and the proportion of active material. The embodiment verifies that increasing the active material loading while ensuring battery performance will continuously improve the battery's energy density.

[0251] A soft-pack lithium metal battery was prepared using lithium-rich oxide A-2 as the positive electrode active material, a composite lithium metal anode, the PE flexible composite current collector from Example 4, an electrolyte with 0.01M lithium bis(trifluoromethanesulfonyl)imide additive, the LATP-coated separator from Example 5, and the cell manufacturing technology from Example 4. The difference lies in the positive electrode coating process, where the electrode coating thickness was increased from 500 μm to 550 μm (active material ratio 97.6%, areal loading 37.26 mg / cm²). 2 While increasing the electrode thickness, the discharge cutoff voltage was further reduced to 1.25V. The battery electrolyte filling coefficient is 1.55g / Ah, and the battery design capacity is 10Ah (based on a discharge cutoff voltage of 2V).

[0252] The resulting battery was charged to 4.8V with a current of 1A, and then discharged to 1.25V; the charge-discharge curve is as follows. Figure 9 As shown in Table 6, the electrochemical performance data are as follows.

[0253]

[0254] Table 6

[0255] Test results show that the battery can still perform normal charge-discharge cycles even with increased coating thickness. Due to the lower discharge cutoff voltage, the battery releases more capacity, with the initial discharge capacity exceeding 12 Ah, a mass energy density of 721.91 Wh / kg, and a volumetric energy density of 1532.12 Wh / L. The second discharge capacity shows no significant decrease compared to the first, without any sharp drop. The charge-discharge curves from the first two tests show that the loss of active lithium at the negative electrode at the end of the first charge-discharge cycle is significantly greater than 10%. This indicates that the coating thickness and charge-discharge voltage range further improve the battery's energy density while maintaining battery performance.

[0256] Example 9

[0257] Electrolyte accounts for a significant portion of the battery's mass, and once the battery system is established, the amount of electrolyte injected directly affects the battery's energy density. This embodiment focuses on exploring the optimal amount of electrolyte, while also considering energy density and performance.

[0258] A soft-pack lithium metal battery was prepared using lithium-rich oxide A-2 as the positive electrode active material, a composite lithium metal anode, the PE flexible composite current collector from Example 4, an electrolyte with 0.01M lithium bis(trifluoromethanesulfonyl)imide additive, the LATP-coated separator from Example 5, and the cell manufacturing technology from Example 4. The difference lies in the electrolyte injection amounts: 2 g / Ah (battery 91), 1.5 g / Ah (battery 92), and 0.7 g / Ah (battery 93), respectively. The designed capacity of the battery was 10 Ah (calculated at a discharge cutoff voltage of 2V). Simultaneously, the discharge cutoff voltage of all batteries was reduced to 1.25V.

[0259] The three types of batteries were charged to 4.8V with a current of 1A, and then discharged to 1.25V; the charge-discharge curves are as follows. Figure 10 As shown in Table 7, the electrochemical performance data are as follows.

[0260]

[0261] Table 7

[0262] Test results show that when the electrolyte level is reduced from 2 g / Ah to 0.7 g / Ah, the battery cell can no longer function properly. At this point, the electrolyte cannot wet the electrodes, preventing ion transport. With an electrolyte level of 2 g / Ah, the battery's initial discharge mass energy density is 633.27 Wh / kg, and its volumetric energy density is 1268.31 Wh / L. However, with an electrolyte level of 1.5 g / Ah, the initial discharge mass energy density is 727.66 Wh / kg, and the volumetric energy density is 1654.29 Wh / L. Therefore, in both normally functioning battery sets, the loss of active lithium at the negative electrode after the first charge-discharge cycle significantly exceeds 10%. The charge-discharge results demonstrate that reducing the electrolyte level by only 0.5 g / Ah can increase the battery's energy density by 14.91%. Proper electrolyte addition is crucial for improving battery energy density.

[0263] Example 10

[0264] Electrolyte is an essential component of lithium-ion batteries; too much or too little electrolyte will negatively impact battery performance. Since electrolyte mass accounts for a significant portion of battery mass, developing high-energy-density batteries requires minimizing electrolyte usage. Introducing solid-state electrolytes can improve cell conductivity while reducing electrolyte consumption, making it a promising technological solution for increasing cell energy density.

[0265] This embodiment uses lithium-rich oxide A-1 as the positive electrode active material, a composite lithium metal anode, the PE flexible composite current collector from Example 4, an electrolyte with 0.01M lithium bis(trifluoromethanesulfonyl)imide additive, the LATP-coated separator from Example 5, and the cell manufacturing technology from Example 4 to prepare a corresponding soft-pack lithium metal battery. The difference lies in the mixing process of the positive electrode material; 5% by mass of solid polymer electrolyte PAN (denoted as electrolyte 1) and 5% by mass of solid polymer electrolyte PEO (denoted as electrolyte 2) are added to the lithium-rich oxide A-1. The designed capacity of the battery is 10Ah. Introducing the solid electrolyte reduces the electrolyte injection volume from 2g / Ah to 1.8g / Ah.

[0266] The two types of batteries were charged to 4.8V with a current of 1A, and then discharged to 2V; the charge-discharge curves are as follows. Figure 11 As shown in Table 8, the electrochemical performance data are as follows.

[0267]

[0268] Table 8

[0269] According to the test results, reducing the electrolyte concentration has a significant impact on battery energy density. The mass energy density of both types of cells exceeded 600 Wh / kg. The mass energy density of the cell with electrolyte 2 added to cathode material A-1 reached 612.5 Wh / kg, higher than the battery without solid electrolyte and with normal electrolyte filling. Its volumetric energy density also exceeded 1100 Wh / L, reaching 1185.4 Wh / L. Although the mass energy density and volumetric energy density of cathode material A-1 with electrolyte 1 were slightly lower than those with electrolyte 2 added, they still exceeded those of the normally electrolyte-filled battery. This result indicates that the introduction of solid electrolyte can significantly reduce electrolyte usage and thus improve battery energy density.

[0270] Example 11

[0271] Unlike liquid electrolyte solutions, solid electrolytes are safer. When solid electrolytes are used as the ion carriers, battery energy density can be increased while battery safety can be significantly improved.

[0272] This embodiment uses lithium-rich oxide A-1 as the positive electrode active material, a composite lithium metal negative electrode, and the PE flexible composite current collector from Example 4. In the positive electrode preparation stage, 3% by mass of solid polymer electrolyte PAN and 3.5% by mass of solid inorganic electrolyte LATP are added. Except for the addition of the solid electrolyte, the preparation method of the positive electrode sheet is the same as in Example 4, and the preparation method of the negative electrode sheet is also the same as in Example 4. The inorganic solid electrolyte LATP particles, solid polymer PAN, and lithium bis(trifluoromethanesulfonyl)imide are compounded at a mass ratio of 1:6:2 to form a composite solid electrolyte film with a thickness of 12 μm. The solid electrolyte film is then cut to a size of 78 × 65 mm using a die-cutting machine. The positive and negative electrodes and the electrolyte film are then laminated in multiple layers. Subsequently, the cell undergoes tab welding, encapsulation, formation, secondary sealing, and capacity testing to finally obtain an all-solid-state soft-pack battery. The designed capacity of this battery is 10 Ah.

[0273] The obtained battery was placed in a variable-temperature oven for testing, with the oven temperature maintained at 55℃. It was charged to 4.8V with a current of 500mA and then discharged to 2V; the charge-discharge curve is shown below. Figure 12 As shown in the figure. According to the experimental results, when the liquid electrolyte is replaced with an all-solid electrolyte, the cell's initial mass energy density and volumetric energy density are close to those of liquid batteries or hybrid solid-liquid batteries, reaching 621.47 Wh / kg and 1286.72 Wh / L, respectively. After 200 cycles, more than 90% of the capacity remains. This indicates that this battery system is also suitable for all-solid-state battery systems.

[0274] Example 12

[0275] A battery is a complex integrated energy storage system. Changes in any component will affect the overall performance of the battery, and improvements in battery performance are the result of changes in all factors. The aforementioned embodiments explored the impact of changes in certain components on battery performance. Based on the aforementioned research results, this embodiment further explores the impact of voltage range on battery performance at the cell level.

[0276] A corresponding soft-pack lithium metal battery was prepared using a solid polymer electrolyte PEO (containing 5% by mass of lithium oxide A-2+) as the positive electrode material, a composite lithium metal anode, a PE flexible composite current collector as described in Example 4, an electrolyte with 0.01M lithium bis(trifluoromethanesulfonyl)imide additive, an LATP-coated separator as described in Example 5, and the same electrolyte injection volume and cell manufacturing technology as described in Example 4. The electrolyte injection coefficient was 1.2 g / Ah, and the designed capacity of the battery was 10 Ah (based on a discharge cutoff voltage of 2V). The difference was that the battery discharge cutoff voltage would be 1.25V.

[0277] The resulting battery was charged to 4.8V with a current of 1A, and then discharged to 1.25V; the charge-discharge curve is as follows. Figure 13 As shown in Table 9, the electrochemical performance data are as follows.

[0278]

[0279] Table 9

[0280] According to the test results, the battery's mass energy density is 851.32 Wh / kg, and its volumetric energy density also exceeds 1800 Wh / L, reaching 1864.17 Wh / L. This is the highest energy density reported to date.

[0281] Comparative Example 1

[0282] Fabricating high-energy-density battery cells places strict requirements on the discharge specific capacity of electrode materials. Both positive and negative electrode active materials must possess high discharge capacity, thereby reducing the amount of active material used and thus increasing the battery's energy density. This invention utilizes lithium-rich oxide Li... x M y O z S m F n As a layered oxide material with the highest discharge specific capacity, the commonly used commercial anode material at present is carbonaceous. This embodiment aims to explore whether conventional commercial anodes can be used to develop high specific energy cells.

[0283] Coin cells were fabricated using lithium-rich oxide A-1, commercially available electrolyte, separator, and current collector. The coin cell fabrication process was consistent with that described in Example 1. It should be noted that the positive electrode coating thickness was 200 μm, and the negative electrode was a commercially available mesophase carbon microsphere (MCMB). The negative electrode preparation process was the same as the positive electrode preparation process, with a slight excess of negative electrode material, resulting in an N / P ratio of 1.05-1.1.

[0284] Button cell assembly: The obtained positive electrode sheet was punched into a Φ12mm circular sheet, and the negative electrode sheet was punched into a Φ14mm circular sheet. The positive electrode sheet was dried in a vacuum drying oven at 120℃ for 12 hours, and the negative electrode sheet was dried in a vacuum drying oven at 80℃ for 12 hours. Then, CR2016 button cells were assembled in a vacuum glove box. The cells were charged to 4.8V at a current density of 25mA / g, then discharged to 2V, and cycled at a current density of 50mA / g. The charge-discharge curves and cycle performance curves are shown below. Figure 14 As shown.

[0285] Figure 14 a represents the charge-discharge curves of the battery at week 1 and week 50. When mesophase carbon microspheres (MCMB) were used as the anode material, the coin cell exhibited normal charge-discharge behavior, but its initial coulombic efficiency and discharge specific capacity were significantly lower than those of batteries using lithium metal as the anode. The initial discharge specific capacity was 192.89 mAh / g, and the initial coulombic efficiency was 67.92%. After 50 cycles, the battery retained a discharge specific capacity of 142.48 mAh / g, representing 73.87% of the initial discharge capacity, which is also far lower than that of batteries using lithium metal as the anode. Figure 14 b represents the battery's cycle performance curve. The initial discharge specific energy (specific energy of the material energy level, i.e., for a lithium half-cell) of the battery material is 666.71 Wh / kg, far lower than that of batteries using metallic lithium as the negative electrode. After 50 cycles, the remaining specific energy of the battery material is 485.05 Wh / kg. This value only represents the specific energy at the material level and does not account for the proportion of the negative electrode, auxiliary materials, etc. It is even lower than the mass energy density of a pouch cell full cell using metallic lithium as the negative electrode.

[0286] The lithium-rich oxide A-1 cathode, MCMB anode, commercial electrolyte, separator, and current collector were assembled into a pouch cell according to the process described in Example 4. The battery's discharge mass energy density was 350 Wh / kg, and its volumetric energy density was 660 Wh / L. It is evident that its energy density is far lower than that of this invention.

[0287] Comparative Example 2

[0288] To produce battery cells with high energy density, it is necessary to increase the mass proportion of active materials in the entire battery while minimizing the mass of auxiliary materials. While a decrease in the active material content may allow the battery materials to perform at their normal capacity, it is detrimental to improving the battery's energy density. This embodiment discusses the change in battery mass energy density when the proportion of active materials decreases.

[0289] A pouch cell was fabricated using lithium-rich oxide A-2 from the aforementioned embodiments as the positive electrode, a silicon-based negative electrode, an electrolyte, a separator coated with alumina on both sides, copper foil, and aluminum foil current collectors. The fabrication process for the pouch cell was the same as described in Example 4. It should be noted that the active material content of the positive electrode sheet was 80%, and the areal loading was 8 mg / cm³. 2 The coated positive electrode sheet is cut directly without rolling, and its compaction density is 1.8 g / cm³. 3 The battery's design capacity (calculated based on the active material) is 2Ah. Considering that the electrolyte wetting of the unrolled electrodes requires a larger amount, the electrolyte injection rate is 2g / Ah.

[0290] Charge the battery to 4.8V with a current of 0.2A, then discharge it to 2V; the battery charge / discharge curve is as follows. Figure 15 As shown in Table 10, the electrochemical performance data are as follows.

[0291]

[0292] Table 10

[0293] According to the test results, even with reduced active material content and no electrode rolling, the full cell can still undergo normal charge-discharge cycles, and the coulombic efficiency remains at a high level. However, for the same mass, its discharge capacity is lower than that of batteries with higher compaction density, higher active material content, and higher areal loading, reaching only 1.808 Ah, with a gravimetric energy density of only 318.5 Wh / kg and a volumetric energy density of 640.8 Wh / L. This level is not significantly different from existing battery manufacturing technologies and does not possess the advantage of high specific energy. Therefore, the electrode sheets for high-specific-energy cells should have high compaction density, high areal loading, and a high proportion of active material.

[0294] Comparative Example 3

[0295] Besides the cathode material system of this invention, among the various cathode materials currently available for practical application, lithium cobalt oxide cathodes possess both specific capacity and high voltage, showing significant development potential. To verify whether materials other than those described in this invention can achieve the mass energy density and volumetric energy density described in this invention, lithium cobalt oxide was selected as the cathode active material for verification.

[0296] A pouch cell was fabricated using lithium cobalt oxide as the positive electrode, lithium alloy as the negative electrode, commercially available electrolyte, separator, and current collector. The fabrication process for the pouch cell was the same as described in Example 4. It should be noted that, except for the change in the positive electrode active material, the battery fabrication process was identical to that described in Example 4. The designed capacity of the battery (calculated based on the active material) was 10 Ah, and the electrolyte injection volume was 2 g / Ah.

[0297] Charge the battery to 4.3V with a current of 1A, then discharge it to 1V; the battery charge / discharge curve is as follows. Figure 16 As shown in Table 11, the electrochemical performance data are as follows.

[0298]

[0299] Table 11

[0300] According to the test results, the battery capacity was normal during the first charge cycle. However, during discharge, after the voltage dropped below 3.8V, the voltage plummeted, and the battery capacity did not increase during this process. When the voltage continued to drop to 1.2V, a relatively long discharge plateau appeared. At this point, the positive electrode material structure had changed, no longer maintaining the layered structure of lithium cobalt oxide. The battery discharge capacity was 41.2Ah. Most of this capacity was obtained through the structural transformation of the material. Although the cell discharge capacity was high, the low voltage plateau lowered the average voltage, resulting in a cell capacity of only 482.85Wh / kg and a volumetric energy density of 805.57Wh / L. Neither cell parameter value met the values ​​described in this invention. The second charge-discharge values ​​show that the battery curves almost do not overlap with the first charge-discharge curves, indicating that the structural phase change caused by low voltage cannot be recovered during the charging process. This suggests that the material is irreversible in this voltage range and cannot undergo a third stable charge-discharge cycle. Furthermore, it is impossible to improve the mass energy density and volume energy density by expanding the charge-discharge voltage range. This further confirms that the material selection and cell design of this invention cannot be achieved by simple selection or replacement.

[0301] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-energy-density lithium battery, characterized in that, The high-energy-density lithium battery includes: a positive electrode structure, a lithium-containing negative electrode structure, a liquid electrolyte and / or a solid electrolyte; The positive electrode structure includes the positive electrode active material Li. x M y O z S m F n And / or its composite materials, wherein 1 / 4≤x / z≤2, 1 / 2≤x / y≤6, 0<m / y≤5 / 2, 0<n / y≤3, and 1≤x≤2, 0<y≤1, 2≤z≤6, 0<m≤1 / 2, 0<n≤1, and M is two or more of Ni, Co, Mn, Al, Cu, Fe, Mg, Ti, Zn, Cr, V, Zr, and Nb; the mass ratio of the positive electrode active material in the positive electrode structure is ≥92%, and the areal loading of the positive electrode active material is ≥20 mg / cm³. 2 The positive electrode active material has a monoclinic / trigonal composite layered structure. The positive electrode structure also includes conductive carbon; specifically, the conductive carbon has an electronic conductivity of 10. 2 Conductive carbon with a strength of S / cm or higher; The compacted density of the electrode sheet in the positive electrode structure is >2.2 g / cm³. 3 ; The lithium-containing anode structure includes an anode material, which comprises one or more of metallic lithium, lithium alloy, pre-lithiated silicon-based anode, and pre-lithiated carbon-based anode; wherein the thickness of the anode material ranges from 5 to 160 μm; and the mass of active lithium contained per unit area on one side of the lithium-containing anode structure is ≥0.26 mg / cm³. 2 ; The mass ratio of the electrolyte and / or solid electrolyte to the battery capacity is 0.5-2.0 g / Ah; The high-energy-density lithium battery has a wide electrochemical potential window and is an asymmetric charge-discharge battery in its first cycle. The upper limit of the charging cutoff voltage is between 4.5V and 5.8V, and the lower limit of the discharging cutoff voltage is between 0.5V and 2.0V. Within this wide electrochemical potential window, the high-energy-density lithium battery has a gravimetric energy density of 500-1300Wh / kg and a volumetric energy density of 900-2500Wh / L. The high-energy-density lithium battery has a first-cycle discharge capacity greater than its first-cycle charge capacity under the wide potential electrochemical window; and a first-cycle coulombic efficiency greater than 110%. After the first discharge cycle of the high-energy-density lithium battery under the wide potential electrochemical window, the active lithium content in the lithium-containing anode structure is reduced by more than 10% compared with the active lithium content in the original lithium-containing anode structure before the first discharge cycle, and the lithium content in the positive electrode active material is greater than the lithium content in the positive electrode active material before the first charge and discharge cycle.

2. The high energy density lithium battery according to claim 1, characterized in that, The upper limit of the charging cutoff voltage of the wide potential electrochemical window is between 4.62 V and 5.0 V, and the lower limit of the discharging cutoff voltage is between 1.0 V and 1.5 V.

3. The high energy density lithium battery according to claim 1 or 2, characterized in that, The conductive carbon includes one or more of the following: carbon nanotubes, graphene, conductive carbon black, carbon fiber, and conductive graphite.

4. The high energy density lithium battery according to claim 3, characterized in that, The content of the conductive carbon is ≥0.005wt%.

5. The high energy density lithium battery according to any one of claims 1-2, characterized in that, The composite material of the positive electrode active material also includes one or more of the following: oxides, fluorides, sulfides, polymers, ionic conductors, and weak acids; The oxides include one or more of manganese dioxide, magnesium oxide, lanthanum oxide, zirconium oxide, tungsten oxide, tin oxide, aluminum oxide, titanium oxide, cerium oxide, and niobium oxide; the fluorides include one or more of fluorinated graphite, iron fluoride, copper fluoride, titanium fluoride, chromium fluoride, cobalt fluoride, and bismuth fluoride; the sulfides include one or more of cobalt sulfide, nickel sulfide, sublimed sulfur, molybdenum sulfide, sodium sulfide, and magnesium sulfide; the polymers include one or more of polyacrylonitrile, polyphosphazene, polyurethane, and polycarbonate; the ionic conductors include one or more of lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich layered oxides, lithium nickel manganese oxide, lithium aluminum titanium phosphate, and aluminum phosphate; the weak acids include one or more of ammonium bicarbonate, ammonium carbonate, oxalic acid, benzoic acid, boric acid, and citric acid.

6. The high energy density lithium battery according to any one of claims 1-2, characterized in that, The positive electrode structure and the negative electrode structure each further include a current collector, which includes one or more of copper foil, aluminum foil, stainless steel foil, titanium foil or flexible composite current collector; the flexible composite current collector is composed of an intermediate layer containing a polymer and multiple conductive layers, and the multiple conductive layers include at least two conductive layers located on both sides of the intermediate polymer layer.

7. The high energy density lithium battery according to claim 6, characterized in that, The thickness of the copper foil is ≤9μm, the thickness of the aluminum foil is ≤15μm, the thickness of the stainless steel foil is ≤10μm, and the thickness of the titanium foil is ≤9μm.

8. The high energy density lithium battery according to claim 7, characterized in that, The thickness of the intermediate polymer layer is 1-20 μm; the conductive layer is made of one or more of metallic conductive materials, non-metallic conductive materials, or composite conductive materials, and has a thickness of 0.005-3 μm.

9. The high energy density lithium battery according to claim 6, characterized in that, The intermediate polymer layer is made of one or more of PET, PP, PE, and PI; the conductive layer is made of one or more of conductive carbonaceous materials, conductive ceramics, Al, Cu, Ni, Ti, Sn, Ag, Au, Fe, and stainless steel.

10. The high energy density lithium battery according to claim 6, characterized in that, The negative electrode material has a passivation layer at the interface between itself and the current collector; the passivation layer includes one or more of elemental metals, carbonaceous materials, and metal oxides, and has a thickness of 10 nm to 2 μm.

11. The high energy density lithium battery according to claim 10, characterized in that, The passivation layer is a lithium-loving passivation layer, which is prepared on the surface of the negative electrode current collector by any one of electrochemical deposition, chemical vapor deposition, physical vapor deposition or solution impregnation.

12. The high-energy-density lithium battery according to any one of claims 1-2, characterized in that, The solid electrolyte includes one or more of the following: polymer solid electrolyte, inorganic solid electrolyte, and composite solid electrolyte formed by polymer and inorganic compound; The polymer solid electrolyte includes one or more of the following: polyolefin, polyether, polynitrile, polyester, polyacrylate, polycarbonate, polyurethane, polyurea, polysulfone, and polysiloxane electrolytes; The inorganic solid electrolyte includes one or more of the following: oxides, sulfides, halides, phosphates, and nitrides; in the composite solid electrolyte, the polymer is the polymer solid electrolyte, and the inorganic compound includes the inorganic solid electrolyte and / or inert inorganic substances. The electrolyte comprises: a lithium salt used as an electrolyte, a solvent, and additives.

13. The high energy density lithium battery according to claim 12, characterized in that, The polymer solid electrolyte includes one or more of the following: polyethylene oxide, polypropylene oxide, polyethylene glycol dimethyl ether, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, polyvinyl chloride, polymethyl methacrylate, polyacrylic acid, polytetrafluoroethylene, polystyrene, polyvinylidene fluoride-hexafluoropropylene, polyvinyl alcohol, polyvinyl formal, polymethyl methacrylate, polyethylene glycol methacrylate, and polyetheramine. The inorganic solid electrolyte includes: Li 1+x Al x Ti 2-x (PO4), 0≤x≤0.5, Li 1+x Al x Ge 2-x (PO4), 0≤x≤0.5, LLZO and its modified derivatives, Li 7-x La3Zr 2-x Ta x O 12 , 0≤x≤2、Li3Zr2Si2(PO4) 12 LLTO and its modified derivatives, LiPON, Li3N, Li3OCl, Li 10 GeP2S 12 LiPS and its modified derivatives, Li₂ZrCl₆, Li₃InCl₆, Li₃YCl₆, Li x ScCl 3+x , 1≤x≤4、Li3ErCl6; The inert inorganic materials include Al2O3, SiO2, TiO2, ZrO2, BaTiO3, and SrBi4Ti4O. 15 One or more of carbon nanotubes.

14. The high-energy-density lithium battery according to claim 12, characterized in that, The solid electrolyte also contains lithium salts.

15. The high-energy-density lithium battery according to claim 12, characterized in that, The solid electrolyte is a composite solid electrolyte composed of a polyester electrolyte and the inorganic compound.

16. The high-energy-density lithium battery according to claim 12, characterized in that, The electrolyte is a high-voltage resistant liquid electrolyte with an electrochemical window oxidation potential ≥ 4.5V; The solvent is an ester solvent; The electrolyte injection volume is in the range of 0.8 g / Ah to 1.8 g / Ah.

17. The high-energy-density lithium battery according to any one of claims 1-2, characterized in that, The lithium battery also includes a separator, which includes one or more of the following: polyethylene separator, polypropylene separator, composite separator formed of double or multiple layers of polyethylene and polypropylene, polyaramid separator, cellulose separator, polyvinylidene fluoride separator, and polyimide separator.

18. The high energy density lithium battery according to claim 17, characterized in that, The diaphragm has a single-sided coating or a double-sided coating, wherein the double-sided coating is a symmetrical or asymmetrical coating; the coating material includes one or more of inorganic ion conductor materials, inorganic lithiophilic materials, polymer materials or organic-inorganic composite materials; the coating material is in the form of powder particles or thin film, and the coating thickness is 0.02 μm-10 μm.

19. The high-energy-density lithium battery according to claim 18, characterized in that, The inorganic materials in the inorganic ionic conductor materials, inorganic lithiophilic materials, or organic-inorganic composite materials include one or more of oxides, phosphates, and silicon-carbon composite materials.

20. The high-energy-density lithium battery according to claim 19, characterized in that, The inorganic ionic conductor material includes one or more of LATP, LLZO, LiPON, LiPO3, and Li3N, and the inorganic lithiophilic material includes one or more of Si / C, Ag / C, Al2O3, and SiO2.

21. The high energy density lithium battery according to claim 18, characterized in that, The organic materials in the polymer materials or organic-inorganic composite materials include one or more of the following: PVDF, PVDF-HFP, PEO, PAN, PTFE, PMMA, PCA, PDMS, PEG, PEGMEA, PEGDA, PEC, PPC, PTMC, PVC, PCL, and PI.

22. The high energy density lithium battery according to claim 18, characterized in that, The organic-inorganic composite materials include PEO+LLZO, PEO+LAGP, PVDF+LLZO, PVDF+LLTO, PAN+LLZO, and PEO+SiO2 composite materials.

23. The high-energy-density lithium battery according to any one of claims 1-2, characterized in that, The lithium battery also includes lightweight packaging materials.

24. The high energy density lithium battery according to claim 23, characterized in that, The lightweight packaging material includes one or more of metals, alloys, and polymers.

25. The high-energy-density lithium battery according to any one of claims 1-2, characterized in that, The operating temperature range of the high-energy-density lithium battery is -80℃ to 100℃.

26. The high-energy-density lithium battery according to claim 25, characterized in that, The high-energy-density lithium battery operates in a temperature range of 60℃ to 100℃, or -80℃ to -10℃.

27. A lithium battery pack or lithium battery module, characterized in that, The lithium battery pack or lithium battery module includes the high energy density lithium battery as described in any one of claims 1-2.

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