12results about How to "Improve long-term cycle stability" patented technology

The invention relates to the technical field of lithium ion batteries, and discloses a high-nickel ternary positive electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing and sintering a nickel-cobalt-manganese precursor, a lithium source, niobium salt and fused salt. According to the preparation method of the high-nickel ternary positive electrode material provided by the invention, the niobium salt and the molten salt form a liquid phase environment at a relatively low temperature, and the niobium element can efficiently enter a crystal lattice, so that uniform bulk phase doping in a real sense is realized, and the electrochemical stability and the thermal stability are improved; meanwhile, the niobium doping can ensure the rapid and uniform transmission of the lithium source, so that the lithiation is more sufficient, and the lithium-nickel mixed arrangement caused by lithium deficiency is reduced in dynamics.

This invention relates to a lithium-ion battery and an electrical device. The positive electrode active material layer of the lithium-ion battery includes a first coating and a second coating sequentially disposed outwards along the surface of the positive electrode current collector. The first coating comprises lithium iron phosphate, and the second coating comprises lithium manganese iron phosphate. The melting point T of the positive electrode current collector is... m The ratio of the particle size Dv50 of the first coating to the particle size of the negative electrode material is denoted as A, the thickness of the first coating is denoted as B, and the particle size Dn50 of the lithium manganese iron phosphate in the second coating is denoted as C, ranging from 1.2 to 7.7 μm. 3 / ℃. In the lithium-ion battery provided by this invention, a double-layer coating technology is used to improve the positive electrode sheet. A first coating containing lithium iron phosphate is set on the side close to the surface of the positive electrode current collector, giving full play to its advantages of high safety and low risk of fire and explosion; a second coating containing lithium manganese iron phosphate is set on the side away from the positive electrode current collector, which can ensure the energy density of the battery and coordinate the value of the coating to achieve synergistic optimization of safety and energy density.

This invention discloses a method for preparing a surface-modified oxide solid electrolyte, comprising the following steps: S1: reacting an oxide solid electrolyte matrix with a bifunctional ionic liquid modifying compound in the presence of a catalyst under an inert atmosphere to obtain an intermediate of a surface-grafted ionic liquid monomer; S2: subjecting the intermediate obtained in step S1 to a free radical copolymerization reaction with an ethylene glycol divinyl ether monomer in the presence of an initiator, thereby in-situ copolymerizing the grafted ionic liquid monomer and the ethylene glycol divinyl ether monomer to form a polymer coating layer, thus obtaining the surface-modified oxide solid electrolyte. The preparation method of this invention not only eliminates interfacial side reactions through chemical bonding between the ionic liquid modifying compound and residual alkali / hydroxyl groups on the electrolyte surface, but also forms a polyionic liquid / polyether composite coating layer through in-situ copolymerization, possessing both high ionic conductivity and flexible segment characteristics, significantly reducing interfacial impedance and inhibiting lithium dendrite growth.

The application provides an organic lithium-iodine battery based on a two-electron transfer mechanism and a manufacturing method and application thereof. The organic lithium-iodine battery comprises a positive electrode, a negative electrode and an organic electrolyte. The positive electrode active material used by the positive electrode comprises iodide and / or bromide, and the organic electrolyte comprises an organic solvent containing a chlorine-containing additive. The organic lithium-iodine battery uses iodide as the positive electrode active material, thereby avoiding the instability and safety hazards existing in the current I2 positive electrode. The organic solvent containing the chlorine-containing additive is used as the organic electrolyte, and excellent electrochemical performance is provided through a two-electron conversion mode. Compared with a traditional lithium-iodine battery, the organic lithium-iodine battery has higher capacity, energy density and higher output voltage. In addition, the organic lithium-iodine battery has excellent low-temperature insensitivity. At-25 DEG C, the battery realizes 2500 cycles at the cost of 20% capacity decay, and can still work stably at a low temperature of-30 DEG C.

The application relates to the technical field of lithium ion battery materials, and specifically discloses a modified lithium titanium aluminum phosphate material, a preparation method and application thereof. The material comprises a lithium titanium aluminum phosphate material with a chemical formula of Li 1+X Al X Ti 2‑X (PO4)3, wherein the x satisfies 0.3 <= x <= 0.5, the modified lithium titanium aluminum phosphate material is prepared by preparing a lithium titanium aluminum phosphate matrix from a mixture containing a lithium source, an aluminum source, a titanium source, a phosphorus source and an organic reaction medium, and then treating the lithium titanium aluminum phosphate matrix in a sulfur dioxide-containing atmosphere; and the organic reaction medium contains a salicylic acid derivative and a nitrogen-containing compound. The method combines the process of organic reaction medium-assisted gas phase transmission and controllable sintering in a sulfur dioxide atmosphere, effectively solves the problems of uneven element distribution and large grain boundary resistance, and the modified lithium titanium aluminum phosphate material can be used in lithium ion batteries to significantly improve the rate performance and cycle stability of the batteries.

The invention discloses a lignin polyaniline composite binder, preparation thereof and application of the lignin polyaniline composite binder in a hard carbon negative electrode of a sodium-ion battery. The method comprises the following steps: firstly, performing carboxymethylation modification on lignin to obtain carboxymethyl lignin; then, polyhydric alcohol serves as a cross-linking agent, a covalent bond is formed through dehydration condensation of hydroxyl on a molecular chain of the polyhydric alcohol and carboxyl of the carboxymethyl lignin, meanwhile, the polyhydric alcohol, the conductive polyaniline and the carboxyl of the carboxymethyl lignin are subjected to cross-linking compounding through the hydrogen-bond interaction between the hydroxyl of the polyhydric alcohol and amino on a molecular chain of the conductive polyaniline, and the lignin polyaniline composite binder is constructed. According to the composite binder, the compatibility of a hard carbon negative electrode and an ester or ether electrolyte is improved, and the structural integrity of the electrode and a stable SEI film can be effectively maintained in the circulation process, so that the first effect, the circulation stability and the rate capability are remarkably improved.

The application provides a supercapacitor carbon and a preparation method thereof. The preparation method comprises the following steps: firstly, mixing petroleum coke and pitch uniformly to obtain a first material; then, carbonizing the first material under the condition of an oxygen-containing gas to obtain a second material; then, crushing the second material and mixing the second material with alkali to perform primary activation under an inert atmosphere to obtain a third material; then, washing and drying the third material, mixing the third material with pitch and alkali, and performing secondary activation under an inert atmosphere; finally, washing and drying to obtain the supercapacitor carbon. The supercapacitor carbon has mesopore-micropore two-stage pore channels, wherein the mesopore has a pore diameter of 2nm-5nm, and the micropore has a pore diameter of 0.4nm-2nm. The application realizes the short-range through-hole pore channel structure design of the petroleum-based porous material through a combined process, provides a large specific surface area for the formation of an effective double electric layer, guarantees the rapid transmission of electric charges, and significantly improves the long-period cycle stability of the material.

This invention relates to the field of electrochemical energy storage materials and lithium metal battery technology, specifically to an in-situ polymerized solid electrolyte, its preparation method and application, and lithium metal batteries. This in-situ polymerized solid electrolyte is prepared by heating a ring-opening polymerization reaction using 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane as reactants, sodium thiosulfate as an initiator, and lithium salt and plasticizer fluoroethylene carbonate as a precursor solution. This electrolyte possesses numerous amorphous regions, which is beneficial for ion transport, enabling the formation of a self-supporting dense structure. It also ensures close contact with the electrode, resulting in a pure interface that effectively reduces interfacial impedance and avoids side reactions at the electrode interface. Furthermore, it enhances oxidation resistance, broadens the electrochemical window, and inhibits dendrite growth. While achieving good mechanical properties, it also improves the cycle stability and safety performance of the battery. It has excellent application prospects in lithium metal batteries, lithium-ion batteries, solid-state energy storage systems, or flexible electronic devices.

The present application relates to the technical field of magnesium foil material, in particular to a vacuum evaporation magnesium film, a preparation method and application thereof, the magnesium film comprises a substrate and a thin film layer, the material of the thin film layer is magnesium and is covered on the surface of the substrate by vacuum evaporation; the preparation method uses aluminum foil, copper foil, gold foil, silver foil, nickel foil, molybdenum foil, titanium foil, tin foil, stainless steel foil, polymer composite metal foil, metal alloy foil, carbon-coated metal foil, polyimide and high polymer material as the substrate, a layer of high-purity magnesium thin film is uniformly deposited on the surface of the substrate by controlling the vacuum evaporation process; when the magnesium film is applied to a magnesium battery, the substrate provides good electrical conductivity and mechanical support, and the magnesium layer directly participates in the electrochemical reaction as an active material, which not only improves the energy density and cycle life of the magnesium battery, but also simplifies the manufacturing process and reduces the cost; the magnesium negative electrode prepared by the method has excellent electrochemical performance and stability, and has good application prospect.

The invention discloses a carbon felt electrode for an all-vanadium redox flow battery as well as a preparation process and application of the carbon felt electrode, and relates to the field of redox flow batteries. The preparation process of the carbon felt electrode for the all-vanadium redox flow battery comprises the following steps: immersing a carbon felt into a urea solution, adding a mixed solution of a bismuth source, polyvinylpyrrolidone and a nitric acid aqueous solution, reacting at a first temperature, cooling, taking out and washing to obtain a carbon felt loaded with a bismuth composite layer; and immersing the carbon felt loaded with the bismuth composite layer into a mixed solution formed by a transition metal source and an organic ligand, reacting at a second temperature, cooling, taking out, washing, performing suction filtration and drying to obtain the carbon felt electrode. Through two heating reactions, a bismuth composite layer is formed on the carbon felt, and a Co-MOF skeleton structure or a Fe-MOF skeleton structure is formed on the bismuth composite layer through in-situ growth, so that the active sites and hydrophilicity of the carbon felt electrode are improved, and the electrochemical performance of the battery is effectively improved.

The invention relates to a method for preparing a thin-layer carbon-coated positive electrode material by adopting a liquid-phase organic carbon source, which comprises the following steps of: introducing a liquid-phase organic matter serving as a carbon source into a positive electrode active material system such as lithium iron phosphate, forming an adsorption or interface modification structure on the surface of a positive electrode material particle by the carbon source, performing solid-liquid separation, and performing in-situ carbonization under a protective atmosphere to obtain the thin-layer carbon-coated positive electrode material. And constructing a continuous thin-layer carbon coating structure on the surfaces of the positive electrode material particles to obtain the thin-layer carbon coated positive electrode material. The method is simplified in process, convenient to operate, low in cost and suitable for large-scale preparation; the obtained material is good in carbon layer continuity and high in interface stability, and is beneficial to improvement of electronic conductivity and reduction of electrode polarization, so that the rate capability and the cycle stability are improved, meanwhile, the particle surface structure stability can be improved, transition metal dissolution is inhibited in the cycle process, and the long-term cycle stability of an electrode is improved. The method is suitable for various lithium ion battery positive electrode material systems, and is especially suitable for lithium ion batteries with relatively high requirements on rate capability and cycle life.

This invention discloses a hydrogen sensing thin film and a room temperature sensor, belonging to the field of semiconductor gas-sensitive materials and sensor technology. The hydrogen sensing thin film is composed of tungsten oxide (WO3) and highly dispersed Pt-Pd-Ni-Co-Cu-Fe hexa-element high-entropy nano-alloy particles. The sensor includes a SiO2 / Si substrate, interdigitated electrodes disposed on the substrate, and a sensitive thin film covering the surfaces of the electrodes and the substrate. The fabrication method of this invention employs a three-target synergistic magnetron sputtering process, utilizing a high-power pulsed magnetron sputtering (HiPIMS) power supply to drive a pure W target and a strongly magnetic Fe-Co-Ni alloy target respectively, while simultaneously using a DC power supply to drive a non-magnetic Pt-Pd-Cu alloy target. By effectively controlling the oxygen content within the thin film through oxygen flow rate regulation and reactive magnetron sputtering, and based on the phase formation process driven by differences in oxyphilic behavior and high mixing entropy, the phase type and size distribution within the film are controlled to form a controllable tungsten oxide + nano-high-entropy alloy dual-phase structure. Furthermore, a gradient coupling interface with oxygen-rich vacancies and strong metal-support interactions is constructed between the two phases, significantly reducing the potential barrier for hydrogen atom spillover. This hydrogen sensing thin film achieves high sensitivity operation at room temperature, shortened response time, and exhibits excellent resistance to CO poisoning and long-term cycling stability.