High energy density semi-solid lithium battery and method of making same
By employing a composite electrolyte structure of silicon-based anode and mesoporous lithium lanthanum zirconium oxide ceramic framework layer in semi-solid lithium batteries, the problems of energy density and ionic conductivity of semi-solid lithium batteries are solved, achieving high energy density and high stability battery performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI YINRUI BATTERY TECH CO LTD
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-16
AI Technical Summary
Existing semi-solid-state lithium batteries struggle to achieve both high energy density and high ionic conductivity, and the volume effect and interface instability of silicon-based anodes severely limit battery performance.
A semi-solid electrolyte employing a silicon-based anode and a mesoporous lithium lanthanum zirconium oxide ceramic framework layer is formed through a composite structure of the gel layer and the framework layer, creating a "sandwich" type electrolyte. The polymer network of the gel layer and the mechanical support of the framework layer are used to buffer the volume effect and construct a continuous lithium-ion transport path, thereby reducing interfacial impedance.
It improves the battery's energy density and ionic conductivity, enhances the structural stability and safety of the electrodes, reduces energy loss during charging and discharging, and improves the battery's cycle stability and rate performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of semi-solid-state battery technology, and in particular to a high-energy-density semi-solid-state lithium battery and its preparation method. Background Technology
[0002] Traditional commercial lithium-ion batteries primarily use liquid electrolytes, which possess high ionic conductivity and excellent contact with the electrode interface. However, the application of liquid lithium batteries is limited. The organic electrolytes used are flammable and prone to leakage, posing safety hazards. Moreover, their energy density has reached its limit, making it difficult for liquid lithium batteries to meet the requirements of next-generation high-safety, long-range lithium batteries. Therefore, solid-state lithium batteries using non-flammable solid electrolytes hold promise for fundamentally solving the safety issues of lithium batteries and further improving energy density. However, all-solid-state lithium batteries still suffer from low room-temperature ionic conductivity and high electrode / electrolyte solid-solid interface impedance.
[0003] Semi-solid lithium batteries serve as an intermediate route between liquid lithium batteries and all-solid lithium batteries. They possess the high safety of all-solid lithium batteries, reducing the risk of thermal runaway, and can be adapted to high-capacity electrode materials, thereby increasing the energy density of the battery.
[0004] Furthermore, the choice of anode material is crucial for improving the energy density of semi-solid-state batteries. Traditional graphite anodes have a low theoretical specific capacity, making it difficult to meet the development needs of high energy density. In contrast, silicon-based anodes have a significantly higher theoretical specific capacity, making them suitable as high-energy-density anode materials and helping to break through existing energy density limits. However, silicon-based anodes suffer from a severe volume effect, meaning that the lithium extraction-intercalation process leads to dramatic volume expansion. In semi-solid-state lithium battery systems, this volume effect is more likely to cause changes in electrode structure and interfacial instability.
[0005] At the same time, semi-solid batteries have always faced the problem of insufficient ionic conductivity. Since the ionic conductivity of solid materials is lower than that of liquids, the lithium-ion conductivity of semi-solid batteries is lower than that of liquid lithium batteries. In addition, it is difficult to achieve atomic-level close contact between solid electrolyte particles and between the electrolyte and the electrode, resulting in high interfacial impedance, which severely limits the rate performance of the battery.
[0006] Therefore, obtaining a novel semi-solid-state lithium battery with high interface stability, which simultaneously possesses high ionic conductivity and high energy density, is of great significance for developing a high-safety, long-range power battery. Summary of the Invention
[0007] This invention provides a high-energy-density semi-solid-state lithium battery and its preparation method, which can solve the problem that existing semi-solid-state lithium batteries are difficult to achieve both high energy density and high ionic conductivity.
[0008] In a first aspect, the present invention provides a high energy density semi-solid lithium battery, comprising a positive electrode, a negative electrode and a semi-solid electrolyte, wherein the negative electrode is a silicon-based negative electrode; the semi-solid electrolyte comprises a framework layer and a gel layer, wherein the gel layer covers the left and right sides of the framework layer.
[0009] The framework layer is a mesoporous lithium lanthanum zirconium oxide ceramic framework layer;
[0010] The raw materials for the gel layer include a functionalized acrylate gel precursor; the functionalized acrylate gel precursor includes functionalized acrylic monomers, plasticizers and functional additives in a mass ratio of (60-70):(20-30):(10-20).
[0011] More preferably, the silicon-based anode includes either a silicon-carbon anode or a silicon-oxygen anode.
[0012] More preferably, the cathode is a ternary cathode; the ternary cathode material includes any one of lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium manganese iron phosphate, and lithium iron phosphate.
[0013] By adopting the above technical solution, this invention uses a high-capacity silicon-based anode, providing a foundation for obtaining a high-energy-density semi-solid-state battery. Furthermore, the semi-solid electrolyte of this invention has a "sandwich" type composite structure of "gel layer-skeleton layer-gel layer." This structure utilizes the skeleton layer to provide mechanical support and continuous lithium-ion transport channels, ensuring conductivity, while the polymer network of the gel layer fills the gaps, reducing solid-solid interface impedance and buffering the volume effect of the silicon-based anode. This improves the overall conductivity of the electrolyte, indirectly increasing the overall energy density.
[0014] Specifically, the framework layer of this invention uses a mesoporous lithium lanthanum zirconium oxide ceramic framework. Lithium lanthanum zirconium oxide materials possess excellent electrochemical stability, which can be adapted to the high-voltage positive and negative electrode materials of this invention to improve energy density. Furthermore, it exhibits high ionic conductivity at room temperature, providing efficient bulk ion transport as a framework layer for a semi-solid electrolyte. When the silicon anode undergoes volume expansion during charging and discharging, the lithium lanthanum zirconium oxide ceramic framework acts as a mechanical support, limiting the expansion of the silicon-based anode, thereby maintaining the overall dimensional stability and structural integrity of the electrode, preventing overall deformation and cracking. In addition to suppressing volume expansion, the rigid framework layer can also effectively prevent internal short circuits caused by electrode deformation or lithium dendrite growth.
[0015] Meanwhile, the skeleton layer of the present invention has a mesoporous structure, which can greatly increase the contact area between the ceramic skeleton and the gel layers on both sides, forming an anchoring effect, making the gel layer less likely to fall off, and can also alleviate local stress concentration.
[0016] When a simple ceramic sheet comes into contact with the positive and negative electrodes, the interfacial impedance is extremely high. However, in this invention, the framework layer is also coated with a gel layer on both sides. During the preparation process, the gel layer first wets the mesoporous structure of the framework layer before contacting the electrode material, thus creating a continuous, low-impedance lithium-ion transport path. More importantly, when the silicon-based negative electrode expands, the gel layer possesses a certain degree of flexibility and elasticity, allowing for flexible deformation. This maintains close contact between the semi-solid electrolyte and the silicon-based negative electrode, enabling flexible control and simultaneously absorbing the mechanical stress generated by the silicon-based negative electrode. This prevents stress from directly acting on the ceramic framework, which could lead to cracking of the negative electrode and electrolyte, thereby constructing a stable electrode-electrolyte interface layer. This not only maintains good structural stability but also enables the semi-solid battery to have a high energy density.
[0017] Preferably, the functionalized acrylic monomers include polyethylene glycol methyl ether acrylate and sulfonated acrylic monomers in a mass ratio of (6-8):1.
[0018] The raw materials for sulfonated acrylic acid monomers include lithium isophthalic acid-5-sulfonate and glycidyl methacrylate in a mass ratio of (1.7 to 2.0):1.
[0019] Preferably, the sulfonated acrylic acid monomer is prepared according to the following method:
[0020] Lithium isophthalic acid-5-sulfonate was vacuum dried and added together with glycidyl methacrylate to a solvent. Then, a catalyst and a polymerization inhibitor were added, the mixture was stirred until homogeneous, and the temperature was raised to 90-110°C. The mixture was stirred for 6-12 hours, and then precipitated, washed and dried to obtain the final product.
[0021] More preferably, the solvent includes any one of toluene and N,N-dimethylformamide.
[0022] More preferably, the catalyst includes dibutyltin dilaurate; the amount of catalyst added is 0.5 to 1% of the total mass of lithium isophthalate-5-sulfonate and glycidyl methacrylate.
[0023] More preferably, the polymerization inhibitor includes p-hydroxyanisole; the amount of the polymerization inhibitor added is 0.1 to 0.3% of the mass of glycidyl methacrylate.
[0024] By adopting the above technical solution, during the preparation of sulfonated acrylic monomers, the epoxy group in glycidyl methacrylate can undergo a ring-opening reaction with the carboxyl group in lithium isophthalic-5-sulfonate, thereby grafting the lithium sulfonate group onto the acrylic monomer, and then combining it with polyethylene glycol methyl ether acrylate as the matrix material of the gel layer.
[0025] Polyethylene glycol methyl ether acrylate (PEGME) provides a highly flexible backbone, which helps to obtain a soft gel layer polymer network that can adapt to the volume changes of silicon-based anodes, maintain close contact with the electrode, and maintain the integrity of the structure. Secondly, the ether radical groups in PEGME can also provide lithium-ion transport channels and reduce impedance. Its flexible segments can also provide a larger free volume for lithium-ion migration.
[0026] The highly polar sulfonic acid groups in sulfonated acrylic acid monomers can promote the dissociation of lithium salts, releasing more free lithium ions to participate in conduction, thereby improving the conductivity of the semi-solid electrolyte. Furthermore, lithium sulfonate groups can form strong hydrogen bonds with silicon-based anodes, which helps the interface adhesion between the gel layer and the silicon-based anode, and also helps to form an SEI film on the surface of the silicon-based anode, improving the first-cycle coulombic efficiency and energy density.
[0027] The acrylate gel network formed by copolymerizing two different functional monomers can not only dissociate lithium ions through sulfonic acid groups, but also provide a fast ion transport channel through ether oxygen segments, thereby constructing a continuous lithium ion transport network and ensuring high ionic conductivity; it can also provide strong interfacial adhesion when facing the strong volume expansion of silicon-based anodes, preventing the anode from being pulled apart from the electrolyte; and through the formed flexible network structure, it can absorb and buffer the mechanical stress generated by volume expansion like a spring, maintaining the integrity of the electrolytic structure and enabling the battery to always maintain high energy density.
[0028] Preferably, the plasticizer includes succinic anhydride.
[0029] By adopting the above technical solution, a plasticizer is also added during the preparation of the gel layer. On the one hand, the addition of the plasticizer can improve the mobility of the gel matrix chain segments, enabling lithium ions to be transferred quickly. On the other hand, the polar cyano groups contained therein can help provide continuous transport sites and improve conductivity.
[0030] On the other hand, the addition of plasticizer succinic anhydride enables the raw materials of the gel layer to better wet the pores of the mesoporous lithium lanthanum zirconium oxide ceramic framework, thereby greatly reducing the impedance between the framework layer and the gel layer, and between the interface and the semi-solid electrolyte. The reduction of interface impedance can reduce energy loss during the charging and discharging process of the battery, help more energy to be released effectively, and improve the usable energy density of the rate performance.
[0031] Preferably, the functional additives include lithium salt and tannic acid in a mass ratio of (8-15):(2-5).
[0032] More preferably, the lithium salt includes one or more combinations of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium di(oxalato)borate, and lithium di(fluorooxalato)borate.
[0033] By adopting the above technical solution, functional additives are also added to the gel layer. The addition of lithium salt provides a lithium ion source, ensuring the number of charge carriers in the system and guaranteeing the high conductivity of the semi-solid electrolyte. The addition of tannic acid, on the one hand, has a hyperbranched structure containing a large number of phenolic hydroxyl groups, which can form multi-level hydrogen bonds with the gel layer matrix material, thus constructing a hydrogen bond network. When the silicon-based negative electrode expands and generates internal stress, the hydrogen bond network dynamically breaks and reassembles according to the magnitude of the stress, thereby efficiently absorbing and dissipating mechanical energy and avoiding electrolytic structure damage and interface delamination caused by stress concentration.
[0034] On the other hand, tannic acid can also promote the dissociation of lithium salts, increase the concentration of freely moving lithium ions in the system, and construct ordered lithium ion migration channels, thereby synergistically improving ionic conductivity and enhancing interfacial chemical stability.
[0035] Preferably, the raw material for the mesoporous lithium lanthanum zirconium oxide ceramic framework layer includes any one of mesoporous lithium lanthanum zirconium oxide and mesoporous gallium-doped lithium lanthanum zirconium oxide.
[0036] Preferably, the mesoporous lithium lanthanum zirconium oxide ceramic framework layer is prepared according to the following method:
[0037] The inorganic metal compound raw material is dissolved in an acid solvent, and 5-20 wt% of pore-forming agent solution is added. After stirring completely, it is vacuum dried, fumigated with ammonia water for 20-25 hours, and then calcined to obtain mesoporous lithium lanthanum zirconium oxide precursor powder.
[0038] Mesoporous lithium lanthanum zirconium oxide precursor powder is mixed with binder solution to prepare ceramic powder slurry, which is then coated onto a glass plate and immersed in water to obtain ceramic green body; then dried, stacked and forged and sintered at high temperature to obtain the final product.
[0039] More preferably, the acid solvent includes a nitric acid-ethanol solution.
[0040] More preferably, the pore-forming agent includes a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.
[0041] More preferably, the adhesive includes one or more combinations of polyvinyl butyral, polyvinyl alcohol, and polyvinylidene fluoride.
[0042] More preferably, the high-temperature sintering temperature is 1100–1200°C.
[0043] Preferably, the inorganic metal compound raw materials include lithium source compounds, lanthanum source compounds, zirconium source compounds and gallium source compounds in a molar ratio of (6.5-7):(3-3.2):(1.8-2):(0-0.25).
[0044] More preferably, the lithium source compound includes one or more combinations of lithium carbonate, lithium hydroxide, and lithium nitrate; the lanthanum source compound includes one or more combinations of lanthanum oxide, lanthanum hydroxide, and lanthanum nitrate; the zirconium source compound includes one or more combinations of zirconium dioxide and zirconium oxynitrate; and the gallium source compound includes one or more combinations of gallium oxide and gallium nitrate.
[0045] More preferably, the mass-to-volume ratio of the mesoporous lithium lanthanum zirconium oxy precursor powder to the binder solution is (7-9) g: 1 mL.
[0046] By adopting the above technical solution, mesoporous lithium lanthanum zirconium oxy precursor powder is prepared by sol-gel method. A pore-forming agent is added during the process to leave a mesoporous structure during calcination. Then, a ceramic skeleton layer is prepared by tape casting. First, a stable and dispersed slurry is formed, and then it is coated and sintered to obtain a porous ceramic skeleton with certain mechanical strength and ultra-thin thickness.
[0047] The lithium lanthanum zirconium oxide framework itself is a fast ion conductor, while the mesoporous structure further forms an interconnected lithium-ion transport network, reducing ion transport paths and thus improving overall conductivity. Moreover, the mesoporous structure significantly increases the contact area between the ceramic framework layer and the gel layer, creating a mechanical interlocking effect, enhancing interfacial bonding, and thereby improving solid-solid interface contact and reducing interfacial impedance.
[0048] Moreover, the framework layer prepared by the casting method has good mesopore continuity, and the formed framework layer has a certain flexibility and supporting strength, thereby supporting the high-capacity silicon-based anode to perform stably and convert the high specific capacity into usable energy density.
[0049] Preferably, the semi-solid electrolyte is prepared according to the following method:
[0050] Plasticizer and functional additives were added to anhydrous acetonitrile, and after mixing evenly, functionalized acrylic monomers and photoinitiators were added and stirred evenly to obtain functionalized acrylic gel precursor.
[0051] The skeleton layer is vacuum impregnated in the functionalized acrylic gel precursor. After removal, the surface liquid is removed, and then the functionalized acrylic gel precursor is spin-coated on both sides of the skeleton layer. Finally, it is cured by ultraviolet irradiation.
[0052] More preferably, the photoinitiator includes any one of diacetone acrylamide, trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 2-hydroxy-2-methyl-1-phenylpropanone; the amount of photoinitiator added is 0.5 to 2% of the mass of the functionalized acrylic monomer.
[0053] By adopting the above technical solution, a functionalized acrylic gel precursor is first prepared, and then the framework layer is impregnated in the precursor. The gel network fills the mesopores to form mechanical interlocks. Then, after spin coating and photocuring, a gel layer is formed, which ensures that the pores are fully filled and establishes continuous conduction channels. It also ensures that the surface of the framework layer is uniformly covered with the gel layer, optimizing the interfacial contact. The resulting semi-solid electrolyte has a rigid framework that carries ions for rapid transport, and a flexible gel that buffers the volume expansion of silicon, resulting in a semi-solid lithium battery with high stability, high conductivity and high energy density.
[0054] Secondly, the present invention provides a method for preparing a high-energy-density semi-solid-state lithium battery, comprising the following process steps:
[0055] A functionalized acrylate gel precursor is coated on the side of the negative electrode closest to the semi-solid electrolyte.
[0056] Assemble the components in the following order: positive electrode shell, positive electrode, semi-solid electrolyte, negative electrode, steel sheet, spring sheet, and negative electrode shell. After packaging, the product is obtained.
[0057] By adopting the above technical solution, a precursor layer is first coated on the surface of the silicon-based negative electrode before assembling the battery. This can fill the unevenness and pores on the electrode surface, ensuring seamless and uniform physical contact between the electrode and the electrolyte after curing. It can also more effectively dissipate stress, enhance interfacial ion transport, and reduce contact resistance.
[0058] The beneficial effects of this invention are:
[0059] 1. The high energy density semi-solid lithium battery provided by the present invention uses a high specific capacity silicon-based negative electrode and a semi-solid electrolyte with a gel layer, a framework layer and a gel layer structure to buffer the volume effect and increase the ionic conductivity of the semi-solid electrolyte, thereby obtaining a high energy density semi-solid lithium-ion battery.
[0060] 2. The framework layer used in the semi-solid electrolyte of the present invention is a mesoporous lithium lanthanum zirconium oxide ceramic framework, which forms a parallel ion transport channel with the functionalized acrylate gel. Lithium ions can migrate through a dual path of rapid conduction through the framework and transport through the gel network. Moreover, the mesoporous structure increases the contact area between the framework and the gel layer, greatly reducing the solid-solid interface impedance, thereby achieving high ionic conductivity.
[0061] 3. The semi-solid electrolyte of the present invention contains a framework layer that can exert a certain limiting force on the expansion of the silicon anode from the outside, thereby maintaining the overall dimensional stability and structural integrity of the electrode; while the gel layer has a certain degree of flexibility and elasticity, can be compressed as silicon expands, adapt to the volume change of the silicon anode, and can effectively absorb the mechanical stress generated by the silicon anode, thereby improving the safety and cycle stability of the battery. Detailed Implementation
[0062] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0063] Preparation Example
[0064] Preparation Example 1: A semi-solid electrolyte was prepared according to the following method:
[0065] Preparation of sulfonated acrylic acid monomers:
[0066] 19g of lithium isophthalic acid-5-sulfonate was vacuum dried and added together with 10g of glycidyl methacrylate to N,N-dimethylformamide. Then, 0.25g of dibutyltin dilaurate and 0.02g of p-hydroxyanisole were added, stirred evenly, and the temperature was raised to 100℃. The reaction was stirred for 8 hours, and then the product was obtained after precipitation, washing and drying.
[0067] Preparation of mesoporous lithium lanthanum zirconium oxide ceramic framework layer:
[0068] Lithium nitrate, lanthanum oxide, and zirconium dioxide in a molar ratio of 7:3:1.8 were dissolved in a nitric acid-ethanol solution. Then, 10 wt% of a P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer) solution was added. After complete stirring, the mixture was vacuum dried, fumigated with ammonia for 24 hours, and then calcined at 250°C for 3 hours followed by calcination at 800°C for 2 hours to obtain mesoporous lithium lanthanum zirconium oxide precursor powder.
[0069] Mesoporous lithium lanthanum zirconium oxide precursor powder was mixed with 8 wt% polyvinyl butyral solution at a mass-volume ratio of 9 g: 1 mL to prepare a ceramic powder slurry. The ceramic powder slurry was then coated onto a glass plate and immersed in water to obtain a ceramic green body. After drying, stacking and pressing, it was sintered at 1150℃ for 2 hours to obtain the final product.
[0070] Preparation of semi-solid electrolytes:
[0071] Add 25g of plasticizer succinate and 15g of functional additive to anhydrous acetonitrile. The functional additive includes lithium bis(trifluoromethanesulfonyl)imide and tannic acid in a mass ratio of 12:3. After mixing evenly, add 65g of functionalized acrylic monomer and 0.7g of photoinitiator diacetone acrylamide. The functionalized acrylic monomer includes polyethylene glycol methyl ether acrylate and the sulfonated acrylic monomer prepared above in a mass ratio of 7:1. Stir evenly to obtain a functionalized acrylic gel precursor.
[0072] The skeleton layer is vacuum impregnated in the functionalized acrylic gel precursor. After removal, the surface liquid is removed, and then the functionalized acrylic gel precursor is spin-coated on both sides of the skeleton layer. Finally, it is cured by ultraviolet irradiation.
[0073] Preparation Example 2, a semi-solid electrolyte, differs from Preparation Example 1 only in that, during the preparation of the mesoporous lithium lanthanum zirconium oxide ceramic framework layer, the inorganic metal compound raw materials include lithium nitrate, lanthanum oxide, zirconium dioxide and gallium oxide in a molar ratio of 6.9:3:1.8:0.1.
[0074] Preparation Example 3, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation of the sulfonated acrylic monomer, the amount of lithium isophthalic acid-5-sulfonate added is 17g; the functionalized acrylic monomer includes polyethylene glycol methyl ether acrylate in a mass ratio of 6:1 and the sulfonated acrylic monomer prepared above.
[0075] Preparation Example 4, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation of the sulfonated acrylic monomer, the amount of lithium isophthalic acid-5-sulfonate added is 20g; the functionalized acrylic monomer includes polyethylene glycol methyl ether acrylate in a mass ratio of 8:1 and the sulfonated acrylic monomer prepared above.
[0076] Preparation Example 5, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation process of the semi-solid electrolyte, the raw materials of the functionalized acrylic gel precursor include 20g of plasticizer succinate, 10g of functional additives, 65g of functionalized acrylic monomers and 0.7g of photoinitiator diacetone acrylamide, wherein the functional additives include lithium bis(trifluoromethanesulfonyl)imide and tannic acid in a mass ratio of 8:2, and the functionalized acrylic monomers include polyethylene glycol methyl ether acrylate and sulfonated acrylic monomers in a mass ratio of 7:1.
[0077] Preparation Example 6, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation process of the semi-solid electrolyte, the raw materials of the functionalized acrylic gel precursor include 30g of plasticizer succinate, 15g of functional additives, 70g of functionalized acrylic monomers and 0.7g of photoinitiator diacetone acrylamide, wherein the functional additives include lithium bis(trifluoromethanesulfonyl)imide and tannic acid in a mass ratio of 15:5, and the functionalized acrylic monomers include polyethylene glycol methyl ether acrylate and sulfonated acrylic monomers in a mass ratio of 7:1.
[0078] Preparation Example 7, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation process of the semi-solid electrolyte, the functionalized acrylic monomer is only polyethylene glycol methyl ether acrylate.
[0079] Preparation Example 8, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation process of the semi-solid electrolyte, the functionalized acrylic monomer is only a sulfonated acrylic monomer.
[0080] Preparation Example 9, a semi-solid electrolyte, differs from Preparation Example 1 only in that, in the preparation of the semi-solid electrolyte, the functionalized acrylic monomer is glycidyl methacrylate.
[0081] Preparation Example 10 is a semi-solid electrolyte, which differs from Preparation Example 1 only in that the plasticizer succinic acid is not added during the preparation of the semi-solid electrolyte.
[0082] Preparation Example 11 is a semi-solid electrolyte, which differs from Preparation Example 1 only in that tannic acid is not added during the preparation of the semi-solid electrolyte.
[0083] Preparation Example 12, a semi-solid electrolyte, differs from Preparation Example 1 only in that the pore-forming agent P123 is not added during the preparation of the mesoporous lithium lanthanum zirconium oxide ceramic framework layer.
[0084] Preparation Example 13, a semi-solid electrolyte, differs from Preparation Example 1 only in that the mesoporous lithium lanthanum zirconium oxide ceramic framework layer is prepared by the following method:
[0085] Lithium nitrate, lanthanum oxide, and zirconium dioxide in a molar ratio of 7:3:1.8 were dissolved in a nitric acid-ethanol solution. Then, 10 wt% of a P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer) solution was added. After complete stirring, the mixture was vacuum dried, fumigated with ammonia for 24 hours, and then calcined at 250°C for 3 hours followed by calcination at 800°C for 2 hours to obtain mesoporous lithium lanthanum zirconium oxide precursor powder.
[0086] Mesoporous lithium lanthanum zirconium oxide precursor powder was mixed with 8 wt% polyvinyl butyral solution at a mass-volume ratio of 9 g: 1 mL to prepare a ceramic powder slurry, which was then directly pressed into shape and finally sintered at 1150℃ to obtain the final product.
[0087] Preparation Example 14, a semi-solid electrolyte, differs from Preparation Example 1 only in that the semi-solid electrolyte is prepared by the following method:
[0088] Add 25g of plasticizer succinate and 15g of functional additives to anhydrous acetonitrile. The functional additives include lithium bis(trifluoromethanesulfonyl)imide and tannic acid in a mass ratio of 12:3. After mixing evenly, add 65g of functionalized acrylic monomer and 0.7g of photoinitiator diacetone acrylamide. The functionalized acrylic monomers include polyethylene glycol methyl ether acrylate and the sulfonated acrylic monomer prepared above in a mass ratio of 7:1. Stir evenly to obtain a functionalized acrylic gel precursor. Mix the mesoporous lithium lanthanum zirconium oxide precursor powder with the functionalized acrylic gel precursor to obtain the final product.
[0089] Example
[0090] Example 1: A high-energy-density semi-solid-state lithium battery was prepared according to the following method:
[0091] A layer of the functionalized acrylate gel precursor prepared in Example 1 was coated on the side of the silicon-based anode silicon-carbon anode near the semi-solid electrolyte.
[0092] Assemble the following components in the following order: positive electrode shell, positive electrode (i.e., lithium nickel cobalt manganese oxide, model NCM811), semi-solid electrolyte prepared in Preparation Example 1, negative electrode, steel sheet, spring sheet, and negative electrode shell. After encapsulation, the product is obtained.
[0093] Example 2, a high energy density semi-solid lithium battery, differs from Example 1 only in that the semi-solid electrolyte prepared in Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 2.
[0094] Example 3, a high energy density semi-solid lithium battery, differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Example 1 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Example 3; and the semi-solid electrolyte prepared in Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 3.
[0095] Example 4, a high energy density semi-solid lithium battery, differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Example 1 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Example 4; and the semi-solid electrolyte prepared in Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 4.
[0096] Example 5, a high energy density semi-solid lithium battery, differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Example 1 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Example 5; and the semi-solid electrolyte prepared in Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 5.
[0097] Example 6, a high energy density semi-solid lithium battery, differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Example 1 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Example 6; and the semi-solid electrolyte prepared in Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 6.
[0098] Example 7, a high energy density semi-solid lithium battery, differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Example 1 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Example 11; and the semi-solid electrolyte prepared in Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 11.
[0099] Example 8, a high energy density semi-solid lithium battery, differs from Example 1 only in that the semi-solid electrolyte prepared in Preparation Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Preparation Example 13.
[0100] Comparative Example
[0101] Comparative Example 1 is a high-energy-density semi-solid-state lithium battery, which differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Preparation Example 7 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Preparation Example 1; and the semi-solid electrolyte prepared in Preparation Example 7 is replaced with an equal amount of the semi-solid electrolyte prepared in Preparation Example 1.
[0102] Comparative Example 2, a high energy density semi-solid lithium battery, differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Example 8 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Example 1; and the semi-solid electrolyte prepared in Example 8 is replaced with an equal amount of the semi-solid electrolyte prepared in Example 1.
[0103] Comparative Example 3 is a high-energy-density semi-solid-state lithium battery, which differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Preparation Example 9 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Preparation Example 1; and the semi-solid electrolyte prepared in Preparation Example 9 is replaced with an equal amount of the semi-solid electrolyte prepared in Preparation Example 1.
[0104] Comparative Example 4 is a high-energy-density semi-solid-state lithium battery, which differs from Example 1 only in that the functionalized acrylate gel precursor prepared in Preparation Example 1 is replaced with an equal amount of the functionalized acrylate gel precursor prepared in Preparation Example 10; and the semi-solid electrolyte prepared in Preparation Example 1 is replaced with an equal amount of the semi-solid electrolyte prepared in Preparation Example 10.
[0105] Comparative Example 5 is a high-energy-density semi-solid-state lithium battery, which differs from Example 1 only in that the semi-solid-state electrolyte prepared in Preparation Example 12 is replaced with an equal amount of the semi-solid-state electrolyte prepared in Preparation Example 1.
[0106] Comparative Example 6: A high-energy-density semi-solid-state lithium battery was prepared according to the following method:
[0107] A battery cell is made by combining a silicon-based anode (silicon-carbon anode) with a cathode (lithium nickel cobalt manganese oxide, model NCM811). The semi-solid electrolyte prepared in Preparation Example 14 is then injected into the battery cell, followed by sealing, standing, curing, and formation.
[0108] Performance testing
[0109] 1. Energy density test: The energy density of the semi-solid-state lithium batteries obtained in the examples and comparative examples were tested respectively;
[0110] 2. Rate test: Under 25℃ conditions, the semi-solid lithium batteries obtained in the examples and comparative examples were charged at a constant current rate of 1C until the voltage reached 4.25V, and then charged at a constant voltage of 4.25V. When the current decreased to 0.05C, the charging was stopped. After the charging was completed, the batteries were left to stand for 10 minutes and then discharged at a constant current rate of 5C until the voltage dropped to 2.5V. The capacity retention rate and the highest temperature during the rate discharge were tested respectively.
[0111] 3. Cyclic performance test: Under 25°C conditions, the semi-solid lithium batteries obtained in the examples and comparative examples were charged at a charging rate of 1C and discharged at a current of 3C for 500 cycles, and the capacity retention rate after 500 cycles was tested.
[0112] The results of the above experiments are shown in Table 1:
[0113] Table 1 Performance test results
[0114]
[0115] According to Table 1, combined with Examples 1 and 7, it can be seen that the performance of the semi-solid lithium battery is lower than that of Example 1. The reason may be that tannic acid was not added to the gel layer in Example 7. Therefore, the gel layer lacks a dynamic hydrogen bond network for stress dissipation, which makes it easy to generate microcracks during long-term cycling, affecting cycle stability and interface stress buffering capacity, resulting in decreased cycle performance, increased interface impedance, and increased heat generation.
[0116] Combining Examples 1 and 8, it can be seen that the performance of Examples 8 is lower than that of Examples 1. The reason may be that the skeleton layer was prepared by hot pressing in Examples 8, which leads to poor continuity of the mesoporous channels, poor interfacial bonding between the mesoporous layer and the gel layer, decreased cycle stability, and lack of continuous ion channels in the mesoporous layer, resulting in decreased conductivity and rate performance.
[0117] Based on Example 1 and Comparative Examples 1 to 3, it can be seen that the performance of Comparative Examples 1 to 3 is lower than that of Example 1. The reason may be that in Comparative Example 1, the absence of sulfonated acrylic monomer reduces the concentration of free lithium ions, decreases conductivity, reduces the bonding force between the gel layer and the negative electrode, and reduces the interfacial adhesion effect, resulting in a decrease in cycle life. In Comparative Example 2, the absence of polyethylene glycol methyl ether acrylate reduces ion transport channels, significantly decreases flexibility, and makes it difficult to buffer the volume expansion of the silicon-based negative electrode, resulting in a decrease in performance. In Comparative Example 3, the use of conventional acrylic monomers leads to a more significant decrease in performance.
[0118] Combining Example 1 and Comparative Example 4, it can be seen that the performance of Comparative Example 4 is lower than that of Example 1. The reason may be that no plasticizer is added to the gel layer in Comparative Example 4, which reduces the lithium-ion conduction effect, decreases the interfacial wettability between the gel layer and the skeleton layer, and between the gel layer and the electrode, increases the interfacial impedance, and reduces the rate performance.
[0119] Based on Examples 1, 5, and 6, it can be seen that the performance of Comparative Examples 5 and 6 is lower than that of Example 1. This may be because the framework layer in Comparative Example 5 lacks a mesoporous structure, resulting in a significant decrease in the bonding force between the gel layer and the framework layer, increased interfacial impedance, decreased continuity, and poor interfacial stability, leading to performance degradation. In Comparative Example 6, the lithium lanthanum zirconium oxide precursor powder is blended with the gel layer material, resulting in a lack of mechanical support from the framework layer and the inability to form a continuous, fast ion transport path, thus failing to provide rigid constraint to the silicon anode and significantly reducing cycle stability.
[0120] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A high-energy-density semi-solid-state lithium battery, comprising a positive electrode, a negative electrode, and a semi-solid electrolyte, characterized in that, The negative electrode is a silicon-based negative electrode; the semi-solid electrolyte includes a framework layer and a gel layer, with the gel layer covering the left and right sides of the framework layer; The framework layer is a mesoporous lithium lanthanum zirconium oxide ceramic framework layer. The raw material of the gel layer includes a functionalized acrylate gel precursor; the functionalized acrylate gel precursor includes a functionalized acrylic monomer, a plasticizer and a functional additive in a mass ratio of (60-70):(20-30):(10-20); The functionalized acrylic monomers include polyethylene glycol methyl ether acrylate and sulfonated acrylic monomers in a mass ratio of (6-8):
1.
2. The high energy density semi-solid-state lithium battery according to claim 1, characterized in that, The raw materials for the sulfonated acrylic acid monomer include lithium isophthalic acid-5-sulfonate and glycidyl methacrylate in a mass ratio of (1.7-2.0):
1.
3. The high energy density semi-solid-state lithium battery according to claim 2, characterized in that, The sulfonated acrylic acid monomer was prepared according to the following method: Lithium isophthalic acid-5-sulfonate was vacuum dried and added together with glycidyl methacrylate to a solvent. Then, a catalyst and a polymerization inhibitor were added, the mixture was stirred until homogeneous, and the temperature was raised to 90-110°C. The mixture was stirred for 6-12 hours, and then precipitated, washed and dried to obtain the final product.
4. The high energy density semi-solid-state lithium battery according to claim 1, characterized in that, The plasticizer includes succinic anhydride.
5. The high energy density semi-solid-state lithium battery according to claim 1, characterized in that, The functional additives include lithium salt and tannic acid in a mass ratio of (8-15):(2-5).
6. The high energy density semi-solid-state lithium battery according to claim 1, characterized in that, The raw material for the mesoporous lithium lanthanum zirconium oxide ceramic framework layer includes either mesoporous lithium lanthanum zirconium oxide or mesoporous gallium-doped lithium lanthanum zirconium oxide.
7. The high energy density semi-solid-state lithium battery according to claim 6, characterized in that, The mesoporous lithium lanthanum zirconium oxide ceramic framework layer was prepared by the following method: The inorganic metal compound raw material is dissolved in an acid solvent, and 5-20 wt% of pore-forming agent solution is added. After stirring completely, it is vacuum dried, fumigated with ammonia water for 20-25 hours, and then calcined to obtain mesoporous lithium lanthanum zirconium oxide precursor powder. Mesoporous lithium lanthanum zirconium oxide precursor powder is mixed with binder solution to prepare ceramic powder slurry, which is then coated onto a glass plate and immersed in water to obtain ceramic green body; then dried, stacked and forged and sintered at high temperature to obtain the final product.
8. The high energy density semi-solid-state lithium battery according to claim 7, characterized in that, The inorganic metal compound raw materials include lithium source compounds, lanthanum source compounds, zirconium source compounds and gallium source compounds in a molar ratio of (6.5-7):(3-3.2):(1.8-2):(0-0.25).
9. The high energy density semi-solid-state lithium battery according to claim 1, characterized in that, The semi-solid electrolyte is prepared according to the following method: Plasticizer and functional additives were added to anhydrous acetonitrile, and after mixing evenly, functionalized acrylic monomers and photoinitiators were added and stirred evenly to obtain functionalized acrylic gel precursor. The skeleton layer is vacuum impregnated in the functionalized acrylic gel precursor. After removal, the surface liquid is removed, and then the functionalized acrylic gel precursor is spin-coated on both sides of the skeleton layer. Finally, it is cured by ultraviolet irradiation.
10. A method for preparing a high-energy-density semi-solid-state lithium battery, used to prepare the high-energy-density semi-solid-state lithium battery according to any one of claims 1 to 9, characterized in that, The process includes the following steps: A functionalized acrylate gel precursor is coated on the side of the negative electrode closest to the semi-solid electrolyte. Assemble the components in the following order: positive electrode shell, positive electrode, semi-solid electrolyte, negative electrode, steel sheet, spring sheet, and negative electrode shell. After packaging, the product is obtained.