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

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 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 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.