A kind of preparation method of positive plate sandwich structure of li-s battery

A technology of sandwich structure and battery positive electrode, applied in battery electrodes, non-aqueous electrolyte battery electrodes, structural parts, etc., can solve problems such as unfavorable lithium-sulfur battery capacity retention and rate performance, consumption of positive electrode active materials, and failure to meet application requirements. , to achieve the effect of inhibiting the loss of lithium polysulfide, inhibiting the loss of dissolution, and improving electrical conductivity

Active Publication Date: 2021-08-10
XIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, due to the dense deposited film layer attached to the surface of the sulfur positive electrode and physically combined, with the electrochemical reaction during the charge and discharge process, the active sulfur is easy to react with silver to form Ag 2 S, which easily leads to the separation of the silver film, resulting in the failure of the battery during the cycle service process. In the middle and later stages, the capacity is obviously attenuated, the performance of the retention rate is deteriorating, and the application requirements cannot be met.
[0009] 3. The method of electrochemically depositing silver thin films provided by patent CN201210538945 inevitably has chemical corrosion on the positive electrode substrate. At the same time, silver and S in the substrate are easy to react to form Ag 2 S, which consumes the active material of the positive electrode, which is not conducive to Capacity retention and rate performance of lithium-sulfur batteries

Method used

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  • A kind of preparation method of positive plate sandwich structure of li-s battery
  • A kind of preparation method of positive plate sandwich structure of li-s battery
  • A kind of preparation method of positive plate sandwich structure of li-s battery

Examples

Experimental program
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Effect test

Embodiment 1

[0045] With PVDF as binder, conductive carbon black SP as conductive agent, NMP as solvent, and sulfur-carbon composite powder with a sulfur mass content of 90% as active material, according to active material: conductive agent: binder ( Mass ratio) = x: y: (1-x-y) (x = 60 ~ 70, y = 10 ~ 30): the ratio of the remainder, binder: solvent (mass ratio) = 1: (5 ~ 30) ratio The slurry was mixed and ground with NMP, scraped and coated on aluminum foil or copper foil current collector, and then dried in a vacuum oven at 60°C to 75°C for 48 to 72 hours to obtain a positive electrode sheet.

[0046] The positive electrode sheet is placed in an acetone saturated steam chamber at 30° C. to 40° C. for 0.5 to 1 hour of wetting treatment.

[0047] Put the positive electrode sheet into the anode position of the magnetron sputtering chamber through the feeding bin, and keep it in a high vacuum state for 30-60 minutes.

[0048] The metal titanium film is deposited for 20 minutes by using a spu...

Embodiment 2

[0050] With PVDF as binder, flake graphite as conductive agent, NMP as solvent, and high-purity sublimated sulfur as active material, according to active material: conductive agent: binder (mass ratio) = x: y: (1- The ratio of x-y) (x=70, y=10~25), using binder:solvent (mass ratio)=1:(9~30) ratio solution as dispersant, mixing and grinding to obtain slurry, scrape coating on aluminum foil or on a current collector of a conductive carbon film, and then dried in a vacuum oven at 60° C. to 75° C. for 24 to 48 hours to obtain a positive electrode sheet.

[0051] The positive electrode sheet was placed in an ethanol saturated steam room at room temperature for wet treatment for 0.5-1 hour.

[0052] The positive electrode piece is placed in the anode position of the magnetron sputtering chamber, and kept in a high vacuum state for 30-60 minutes.

[0053] Aluminum target is used, argon gas is used as plasma gas source, sputtering power is 30-60W, vacuum chamber pressure is 10 -4 Pa,...

Embodiment 3

[0055] With polyvinyl alcohol as binder, acetylene black as conductive agent, NMP as solvent, and high-purity sublimated sulfur as active material, according to active material: conductive agent: binder (mass ratio) = 70: (10~ 20): The ratio of the remaining amount is mixed and ground according to the ratio of binder: solvent (mass ratio) = 1: (2 ~ 10) to obtain a slurry, which is scraped on the aluminum foil or copper foil current collector, and then heated at 60 ° C ~ Dry in a vacuum oven at 75° C. for 24 to 48 hours to obtain a positive electrode sheet.

[0056] The positive electrode sheet is placed in a saturated steam chamber of ethylene glycol monomethyl ether at 40°C to 50°C for 0.5 to 1 hour of wetting treatment.

[0057] Put the positive electrode sheet into the anode position of the magnetron sputtering chamber in a high vacuum state through the feeding bin, and keep it for 30-60 minutes.

[0058] Using a titanium-aluminum alloy target (with a mass fraction of 10-6...

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Abstract

The invention discloses a method for preparing a sandwich structure of a positive electrode sheet of a Li-S battery. Pre-preparing the exposed pores on the surface of the sulfur cathode sheet, using low-temperature magnetron sputtering to quickly deposit a micro-pore network film of a certain thickness of aluminum, titanium or aluminum-titanium alloy, and form it together with the current collector substrate through the injection and diffusion of metal atoms The sandwich structure of current collector-sulfur cathode sheet-metal deposition film not only improves the conductivity of the sulfur cathode, but also inhibits the diffusion and loss of lithium polysulfide in the electrolyte through the mechanical filtration and chemical adsorption effects of micropores, realizing 1C The charge-discharge specific capacity and cycle capacity retention rate of the lithium-sulfur secondary battery are improved under the high rate.

Description

technical field [0001] The invention belongs to the field of lithium-sulfur secondary batteries, and in particular relates to a sandwich structure of a Li-S battery positive plate and a preparation method thereof. Background technique [0002] With the rapid development of technologies such as communications, electric vehicles, and portable devices, people's demand for high-energy batteries is increasing, and research on lithium-ion secondary batteries with high energy specific energy, environmental friendliness, and low cost has received widespread attention. Pay attention to. Elemental sulfur is used as the positive electrode active material, and its theoretical specific capacity is 1675mAh / g. When assembled with metal, the mass specific energy of the battery is as high as 2500Wh / kg, which is much higher than the energy density that current commercial lithium-ion batteries can provide. Moreover, lithium-sulfur batteries have the advantages of non-toxic elemental sulfur, l...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/13H01M4/139
CPCH01M4/13H01M4/139Y02E60/10
Inventor 张卫华车新川霍文游才印杨蓉
Owner XIAN UNIV OF TECH
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