Sulfur positive electrode of lithium sulfur battery and preparation method

A lithium-sulfur battery and sulfur cathode technology, which is applied in the field of sulfur-based composite materials containing biomass activated carbon and its preparation, can solve the problems of low conductivity of elemental sulfur, hinder ion exchange, loss of active materials, etc., and improve the Coulombic efficiency. and cycle life, reduced shuttle effect, good effect of coating sulfur

Inactive Publication Date: 2014-11-19
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the low electrical conductivity of elemental sulfur severely limits its practical applications.
In addition, due to the long-chain lithium polysulfide (Li 2 S n , 4≤n≤8) will dissolve into the organic electrolyte, causing

Method used

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  • Sulfur positive electrode of lithium sulfur battery and preparation method
  • Sulfur positive electrode of lithium sulfur battery and preparation method
  • Sulfur positive electrode of lithium sulfur battery and preparation method

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Embodiment 1

[0031] 1) Take a certain amount of lychee shells, wash them with water, dry them, and crush them into pieces;

[0032] 2) In a tube furnace, protected by argon, pre-carbonized at 500°C for 2 hours to obtain pyrolyzed litchi shells;

[0033] 3) Take it out and weigh it, mix it with KOH at a mass ratio of 1:4, dissolve KOH with water, stir the mixture fully with a magnet, and let it stand for 1 hour to ensure that the KOH solution completely penetrates into the pyrolyzed litchi shell;

[0034] 4) Then dry the mixture at 100°C with a blast drying oven, and wait for the water to evaporate completely;

[0035] 5) In the tube furnace, protected by argon, and annealed at 900°C for 1 hour to make it completely carbonized;

[0036] 6) After cooling, the sample was washed with 1M HCl solution and deionized water by suction filtration until the pH value reached 7;

[0037] 7) The sample is then dried in a blast drying oven at 80° C. to obtain a biomass activated carbon material.

[00...

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Abstract

The invention provides a preparation method of a sulfur positive material of a lithium sulfur battery. The preparation method comprises the following steps: (a) washing lychee exocarp, drying the lychee exocarp, pulverizing the lychee exocarp into blocks, annealing the lychee exocarp blocks for 2+/-0.5 hours at the temperature of 500+/-50 DEG C under the protection of inert gases to obtain pyrolytic lychee exocarp; (b) activating the pyrolytic lychee exocarp obtained in the step (a) by utilizing KOH, and completely carbonizing the pyrolytic lychee exocarp to obtain biomass active carbon with a large specific surface area; (e) washing the carbonized powder after being cooled in step (d) by utilizing HCl solution and water until the pH value reaches 7; (f) placing the powder obtained in the step (e) into a blowing drying oven to be dried at the temperature of 80+/-10 DEG C to obtain biomass active carbon powder; and (g) mixing the biomass active carbon powder obtained in the step (f) with sulfur powder according to a mass ratio of 0.3 to 1, and grinding the mixture to obtain black mixed powder. The prepared sulfur positive composite material for the lithium sulfur battery is high in specific capacity and long in cycle life, and 51 percent of initial capacity still can be maintained after the lithium sulfur battery is circulated for 800 times.

Description

technical field [0001] The invention relates to a positive electrode material for a secondary battery and a preparation method thereof, that is, a sulfur positive electrode of a lithium-sulfur battery and a preparation method thereof, in particular to a sulfur-based composite material containing biomass activated carbon and a preparation method thereof. Background technique [0002] In applications such as electric vehicles and smart grids, lithium-sulfur batteries have attracted widespread attention due to their very high energy density (theoretical up to 2600Wh / kg). However, the low electrical conductivity of elemental sulfur severely limits its practical applications. In addition, due to the long-chain lithium polysulfide (Li 2 S n , 4≤n≤8) will dissolve into the organic electrolyte, causing the shuttle effect. The shuttling of dissolved polysulfide ions between the sulfur cathode and the lithium anode not only leads to decreased Coulombic efficiency and loss of active...

Claims

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Application Information

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IPC IPC(8): H01M4/36C01B31/02H01M4/62
CPCH01M4/1393H01M4/364H01M4/625H01M10/052Y02E60/10
Inventor 林子夏施毅郑明波张松涛赵斌濮琳
Owner NANJING UNIV
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