Application of titanium boride for chemically trapping polysulfides in lithium-sulfur batteries to prepare cathode materials for lithium-sulfur batteries

Abstract

The invention relates to a titanium boride for chemical trapping of polysulfide in a lithium-sulfur battery as well as a preparation method and application of the titanium boride. The preparation method of the titanium boride comprises the following steps: grinding and uniformly mixing titanium dioxide, a magnesium-containing reducing agent and a boron-containing compound, and adding deionized water to obtain reaction liquid; carrying out hydrothermal reaction at the temperature of 120 to 180 DEG C for 1 to 6 hours; washing and drying to obtain the titanium boride. The prepared titanium boridehas the advantages of high conductivity, simple preparation, low price of raw materials, no toxicity, low energy consumption, low requirements on equipment and capability of realizing batch production; in addition, when the titanium boride is applied to the lithium-sulfur battery, the shuttle problem of the polysulfide in the charge and discharge process of the lithium-sulfur battery can be effectively solved; beside, the titanium boride shows the advantages of high specific capacity, excellent long cycle life, high coulombic efficiency and relieved self-discharge behavior.

Description

technical field

[0001] The invention relates to a titanium boride used for chemically trapping polysulfides in a lithium-sulfur battery, a preparation method and application thereof, and belongs to the technical field of lithium-sulfur battery materials. Background technique

[0002] Due to the low energy density and high cost, the current commercial lithium-ion batteries cannot meet high-power applications, especially in the fields of smart grid and electric vehicles. Lithium-sulfur batteries are 3-5 times the energy density of lithium-ion batteries. At the same time, the advantages of sulfur in the earth's crust, such as abundant reserves, low price, and environmental friendliness, make it one of the most promising secondary batteries for the next generation. However, the actual application of lithium-sulfur batteries is faced with problems such as short cycle life, low Coulombic efficiency, low utilization of active materials, and serious self-discharge phenomenon, which ...

Examples

Embodiment 1

[0044] A titanium boride used for chemically trapping polysulfides in lithium-sulfur batteries, the microscopic appearance of the titanium boride is nanoparticles with a particle size of about 200nm; the titanium boride is a hexagonal crystal phase, and boron atoms are inserted into the A hexagonal structure is formed in the gaps between titanium atomic layers.

[0045] The above-mentioned preparation method of titanium boride used for chemically trapping polysulfides in lithium-sulfur batteries comprises the following steps:

[0046] Hand-grind 1.2g of titanium dioxide, 4.32g of magnesium powder, and 0.3g of boron powder with a mortar for 0.5h, mix them evenly, add them into a stainless steel iron kettle, then add 2.7mL of deionized water, seal it, and put it in an oven at 150°C Thermal reaction for two hours; the reacted product was stirred with 1mol / L hydrochloric acid for 12 hours, then suction filtered, washed with deionized water and ethanol three times respectively to r...

Embodiment 2

[0059] A preparation method of titanium boride used for chemically trapping polysulfides in lithium-sulfur batteries, the preparation steps are as described in Example 1, the difference is that the hydrothermal reaction time is 4 hours, and the others are consistent with Example 1.

[0060] The application of the above-mentioned titanium boride to prepare the positive electrode material of lithium-sulfur battery, the preparation method is as described in Example 1.

Embodiment 3

[0062] A preparation method for titanium boride used in lithium-sulfur batteries to chemically trap polysulfides, the preparation steps are as described in Example 1, the difference is that the amounts of titanium dioxide, magnesium powder, boron powder, and deionized water are respectively 1.36g , 4.9g, 0.34g, 3.06mL, others are consistent with Example 1.

[0063] The application of the above-mentioned titanium boride to prepare the positive electrode material of lithium-sulfur battery, the preparation method is as described in Example 1.

technical field

[0001] The invention relates to a titanium boride used for chemically trapping polysulfides in a lithium-sulfur battery, a preparation method and application thereof, and belongs to the technical field of lithium-sulfur battery materials. Background technique

[0002] Due to the low energy density and high cost, the current commercial lithium-ion batteries cannot meet high-power applications, especially in the fields of smart grid and electric vehicles. Lithium-sulfur batteries are 3-5 times the energy density of lithium-ion batteries. At the same time, the advantages of sulfur in the earth's crust, such as abundant reserves, low price, and environmental friendliness, make it one of the most promising secondary batteries for the next generation. However, the actual application of lithium-sulfur batteries is faced with problems such as short cycle life, low Coulombic efficiency, low utilization of active materials, and serious self-discharge phenomenon, which ...

Examples

Embodiment 1

[0044] A titanium boride used for chemically trapping polysulfides in lithium-sulfur batteries, the microscopic appearance of the titanium boride is nanoparticles with a particle size of about 200nm; the titanium boride is a hexagonal crystal phase, and boron atoms are inserted into the A hexagonal structure is formed in the gaps between titanium atomic layers.

[0045] The above-mentioned preparation method of titanium boride used for chemically trapping polysulfides in lithium-sulfur batteries comprises the following steps:

[0046] Hand-grind 1.2g of titanium dioxide, 4.32g of magnesium powder, and 0.3g of boron powder with a mortar for 0.5h, mix them evenly, add them into a stainless steel iron kettle, then add 2.7mL of deionized water, seal it, and put it in an oven at 150°C Thermal reaction for two hours; the reacted product was stirred with 1mol / L hydrochloric acid for 12 hours, then suction filtered, washed with deionized water and ethanol three times respectively to r...

Embodiment 2

[0059] A preparation method of titanium boride used for chemically trapping polysulfides in lithium-sulfur batteries, the preparation steps are as described in Example 1, the difference is that the hydrothermal reaction time is 4 hours, and the others are consistent with Example 1.

[0060] The application of the above-mentioned titanium boride to prepare the positive electrode material of lithium-sulfur battery, the preparation method is as described in Example 1.

Embodiment 3

[0062] A preparation method for titanium boride used in lithium-sulfur batteries to chemically trap polysulfides, the preparation steps are as described in Example 1, the difference is that the amounts of titanium dioxide, magnesium powder, boron powder, and deionized water are respectively 1.36g , 4.9g, 0.34g, 3.06mL, others are consistent with Example 1.

[0063] The application of the above-mentioned titanium boride to prepare the positive electrode material of lithium-sulfur battery, the preparation method is as described in Example 1.

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