36results about How to "Improve long-term cycle stability" patented technology

The invention provides a positive pole material of a lithium ion battery and a preparation method of the positive pole material. Secondary particles of the positive pole material of the lithium ion battery comprise primary particles of lithium-containing multi-transition metal oxide and second-phase materials; in a process of forming the secondary particles through the primary particles, the second-phase materials form second-phase material layers which are distributed on the surfaces of the primary particles, and are diffused with the lithium-containing multi-transition metal oxide through atoms to form diffusion layers so as to enable the second-phase material layers to be combined with the primary particles. Therefore, pulverization of the secondary particles of the positive pole material of the lithium ion battery along interfaces between the primary particles can be effectively suppressed, and the sizes of the primary particles and the secondary particles can be effectively controlled. When the positive pole material is applied to the lithium ion battery, the lithium ion battery is high in specific capacity, good in cycle performance and good in safety performance.

Electrochemical cells that cycle lithium ions are provided. The electrochemical cells have an electrode that includes a silicon-containing electroactive material that undergoes volumetric expansion and contraction during the cycling of the electrochemical cell; and an electrolyte system that promotes passive formation of a flexible protective layer comprising a lithium fluoride-polymer composite on one or more exposed surface regions of the silicon-containing electroactive material. The electrolyte system includes a lithium salt, at least one cyclic carbonate, and two or more linear carbonates. At least one of the two or more linear carbonate-containing co-solvents is a fluorinated carbonate-containing co-solvent. The electrolyte system accommodates the volumetric expansion and contraction of the silicon-containing electroactive material to promote long term cycling stability.

The invention discloses a method for preparing a silicon negative electrode material containing a surface modification film, which belongs to the technical field of lithium ion batteries. The method is as follows: dissolving the polymer into water, adding silicon material, stirring while heating, removing moisture in the solution, and obtaining silicon material coated with polymer film A; dissolving PAN in NMP solvent, stirring to make it Completely dissolve, add the silicon material coated with the polymer film A and the conductive agent into the PAN solution, stir while heating, remove the NMP solvent in the solution, and obtain a silicon negative electrode material containing a surface modification film. The artificially modified film of the silicon negative electrode invented can satisfy the use of ordinary SBR binders in the silicon carbon negative electrode, so that graphite and silicon negative electrodes can each generate their own SEI film without mutual influence, further improving the cycle stability of the battery . The preparation method of the silicon negative electrode artificially modified membrane described in the present invention is simple and convenient, and can meet the requirements of the conventional water system batching method for the silicon carbon negative electrode.

The invention discloses a water-based zinc-manganese battery fiber with a dual-function protective layer and a preparation method thereof. In the fiber battery of the present invention, the carbon nanotube fiber loaded with manganese dioxide / carbon nanotube film / 3,4-polyethylenedioxythiophene composite material is used as the positive electrode, and the carbon nanotube fiber deposited with zinc is used as the negative electrode, and the two electrodes are intertwined It is obtained by forming a winding structure, injecting liquid electrolyte and packaging; the preparation steps include: preparation of PEDOT / CNT / manganese dioxide / current collector positive electrode, preparation of flexible zinc negative electrode, and assembly of fiber zinc-manganese dioxide full battery. Among them, the carbon nanotube film provides a continuous conductive channel for electron transport during charging and discharging, and enhances the mechanical stability of the battery fiber. PEDOT can enhance the contact between the carbon tube film and manganese dioxide, reduce the poor dissolution of the active material and improve conductivity. Weaving this fiber battery into fabrics can prepare flexible and wearable electronic devices with excellent performance.

Disclosed is a positive electrode material for a lithium-sulfur battery, including a sulfur-containing positive electrode material and a transition metal compound, the transition metal compound can generate a transition metal sulfide when the lithium-sulfur battery is discharged, and the transition metal sulfide is poorly soluble in in the electrolyte. In the positive electrode material of the present invention, in the lithium-sulfur battery system, the transition metal compound will form transition metal sulfide with polysulfide ions in the discharge product. The transition metal sulfide is insoluble in the electrolyte, so it can fix the polysulfide ions in the positive electrode, thereby blocking the shuttling of polysulfide at the root.

The invention belongs to the field of energy materials, and more specifically relates to a porous hollow carbon material loaded with metal phosphides, its preparation and application. First, the carbon sphere precursor is prepared by the template method, and then the metal phosphide is loaded on the surface of the carbon sphere precursor, and finally the template is removed to prepare the porous hollow carbon material to support the metal phosphide. The metal phosphide / hollow porous carbon sphere composite prepared by this method The material has high pore capacity and electrical conductivity, which can improve the poor conductivity and low capacity of the previous lithium-sulfur battery cathode materials. Moreover, the strong adsorption and interaction between transition metal phosphides and polysulfide ions suppresses the migration of polysulfide ions and significantly increases the conversion rate of polysulfide ions, which can effectively improve the rate and cycle performance of lithium-sulfur batteries.

The invention discloses preparation and electrochromic characteristics of a tungsten trioxide / vanadium pentoxide core-shell-structured nanowire array. According to the invention, tungsten trioxide is used as a core and vanadium pentoxide is used as a shell; the lengths of tungsten trioxide nanowires are in a range of 400 to 1000 nm, and the diameters of the tungsten trioxide nanowires gradually decrease from 80 nm to 30 nm; and vanadium pentoxide is of an amorphous porous structure and uniformly coats the nanowires, and after compounding, the diameters of the nanowires are in a range of 100 to 200 nm. An electrochemical workstation and a three-electrode system are employed for electrochemical deposition of vanadium pentoxide onto the surfaces of the tungsten trioxide nanowires prepared through a solvothermal process so as to prepare a core-shell-structured electrochromic material. The tungsten trioxide nanowires grow along a direction perpendicular to a substrate and are uniformly distributed, and vanadium pentoxide is a porous film and uniformly coats the surfaces of the nanowires to form a novel core-shell structure; and the prepared material has excellent electrochromic performance, can realize rapid and reversible conversion among a blue grey color, a yellow green color and an orange yellow color, shows good stability and is applicable to fields like camouflage materials and intelligent chromotropic film materials.