Positive electrode material for lithium-sulfur secondary battery and preparation method of positive electrode material

A lithium-sulfur secondary battery and cathode material technology, which is applied in battery electrodes, lithium storage batteries, non-aqueous electrolyte storage batteries, etc., can solve the problem of reducing the utilization rate of cathode active materials. cycle performance and other issues, to achieve the effects of good cycle performance and rate performance, long service life and simple preparation method

Inactive Publication Date: 2018-02-02
TONGJI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, lithium-sulfur batteries also have some shortcomings that restrict their commercialization process. Among them, the three main shortcomings derived from the positive active material sulfur are: (1) The electronic conductivity of sulfur is extremely low, which is only about 5×10 at room temperature. -30 S cm -1 ), which seriously affects the electrochemical activity of sulfur; (2) sulfur and its discharge product lithium sulfide (Li 2 S) have very different densities (2.07 and 1.66 g cm -3 ), resulting in the destruction of the structure of the positive electrode and th

Method used

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  • Positive electrode material for lithium-sulfur secondary battery and preparation method of positive electrode material

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Embodiment 1

[0027] Cut the waste mangosteen skin into small pieces, wash it with deionized water, and dry it in a blast drying oven at a temperature of 110°C for 12 hours. The dried product is pre-carbonized and the temperature is pre-carbonized. The temperature is 500°C, the reactor is filled with nitrogen (purity above 99%), and the carbonization reaction time is 3 hours. Then, the pre-carbonized product and the potassium hydroxide aqueous solution are mixed, and the quality of the pre-carbonized mangosteen bark and potassium hydroxide The ratio is 1:4. After fully stirring and mixing, first heat it on a magnetic stirrer with heating function to evaporate most of the water, and then place it in a blast drying oven at a temperature of 110°C for 12 hours. Then, The mixture of pre-carbonized product and potassium hydroxide is transferred to a tube furnace, heated to 800°C in a nitrogen atmosphere (purity above 99%) and kept for 3 hours, naturally cooled to room temperature, and washed with h...

Embodiment 2

[0032] The preparation method is similar to that of Example 1, except that:

[0033] (1) The temperature used for pre-carbonization is 300℃, and the time is 7h;

[0034] (2) In potassium hydroxide activation, the mass ratio of potassium hydroxide to pre-carbonized mangosteen bark is 3:1; the activation temperature is 600°C, and the activation time is 5h;

[0035] (3) The mass ratio of activated carbon material carrier to sulfur element is 6:4. The grinding is carried out in a ball milling tank. The rotating speed is 200rpm and the grinding time is 3h. The ground mixture is placed in a vacuum environment at a temperature of 140℃. The cathode material can be obtained by keeping the temperature for 24 hours and cooling.

[0036] The positive electrode material obtained above was made into electrode sheets according to the same method as in Example 1, and then installed in a lithium-sulfur secondary battery. It was verified that the positive electrode material has a high specific discharg...

Embodiment 3

[0038] The preparation method is similar to that of Example 1, except that:

[0039] (1) The temperature used for pre-carbonization is 500℃, and the time is 1h;

[0040] (2) In potassium hydroxide activation, the mass ratio of potassium hydroxide to pre-carbonized mangosteen bark is 5:1; the activation temperature is 900°C, and the activation time is 1h;

[0041] (3) The mass ratio of the activated carbon material carrier to the sulfur element is 2:8, and the grinding is carried out in a ball milling tank with a rotation speed of 500 rpm and a grinding time of 0.5 h. The ground mixture is placed in a vacuum environment at 200 ℃ The positive electrode material can be obtained by keeping the temperature for 6 hours and cooling.

[0042] The positive electrode material obtained above was made into electrode sheets according to the same method as in Example 1, and then installed in a lithium-sulfur secondary battery. It was verified that the positive electrode material has a high specific...

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Abstract

The invention relates to a positive electrode material for a lithium-sulfur secondary battery and a preparation method of the positive electrode material. Particularly, an activated carbon material with ultra-high specific surface area and large pore volume is prepared by adopting biomass waste mangosteen peel as a raw material through pre-carbonization and potassium hydroxide activation methods;and a carbon/sulfur composite material is further prepared by adopting the activated carbon material as a carrier through a melting diffusion method. A test result shows that the initial discharge specific capacity of a positive electrode prepared from the carbon/sulfur composite material with the sulfur bearing capacity of 65% under the current of 0.5C is 870.5mAhg<->, the discharge specific capacity of the positive electrode after 100 cycles is 599.6mAhg<-1> and the discharge capacity after 100 cycles under the current of 2C is 569.2mAhg<->. The carbon/sulfur composite positive electrode material prepared by adopting the biomass waste mangosteen peel as the raw material is high in sulfur bearing capacity, good in chemical stability, high in specific capacity, good in rate capability, simple in preparation method and suitable for the lithium-sulfur secondary battery.

Description

Technical field [0001] The invention relates to the technical field of battery materials, in particular to a positive electrode material for lithium-sulfur secondary batteries and a preparation method thereof. Background technique [0002] With the rapid development of new energy vehicles and portable electronic equipment, the demand for rechargeable secondary batteries with high energy density has increased sharply, and the effective use of renewable and clean energy such as wind, solar, and hydropower is also in urgent need of development. Performance energy storage battery. Among the two most widely used traditional secondary batteries, the development of lithium-ion batteries has approached its theoretical energy density (about 500Wh kg -1 ), and its positive electrode material often contains a large amount of precious metal cobalt, which makes the cost of the battery high. Although the price of lead-acid battery is cheap, its energy density is too low and often cannot be ful...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M4/38H01M10/052
CPCH01M4/362H01M4/38H01M4/583H01M4/625H01M10/052Y02E60/10
Inventor 薛明喆张存满李冰陈晨谭研
Owner TONGJI UNIV
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