Mesoporous carbon material, elemental sulfur and preparation method for mesoporous carbon composite material

Abstract

Provided is a preparation method for a mesoporous carbon material. The preparation method comprises the following steps: pore forming agents and carbon precursors are mixed uniformly and a mixture is obtained, the mixture is processed for 2-3h at the temperature of 120-160 DEG C, and mesoporous carbon precursors are obtained, and the mass ratio of the pore forming agents to the carbon precursors is 4:6-6:4; the mesoporous carbon precursors are subjected to heat treatment at the temperature of 600-900 DEG C and under protection gases, and the mesoporous carbon material is obtained after separation and purification. In the preparation method, a hard template method is employed for preparation of the mesoporous carbon material, the operation is simple, good pore size distribution is achieved, and the mesoporous carbon material facilitates high dispersion of sulfur. In addition, the strong adsorptivity of the material can inhibit dissolution and loss of polysulfides effectively, and the mesoporous carbon material is helpful to raise the utilization rate of active sulfur.

Description

technical field [0001] The invention relates to the field of electrode materials, in particular to a preparation method of mesoporous carbon material, elemental sulfur and mesoporous carbon composite material. Background technique [0002] With the continuous development of human social productivity, people's demand for energy in daily production and life has increased dramatically. To cope with the growing global energy shortage, traditional primary batteries are gradually being replaced by reusable secondary batteries. At the same time, the rapid development of current communications, portable electronic devices, electric vehicles and space technology has put forward higher and higher requirements for battery performance. Traditional secondary batteries have low capacity, poor safety performance and bulky volume. It is not conducive to carrying and is gradually replaced by new lithium secondary batteries. It is of great significance to develop new lithium secondary batte...

AI Technical Summary

Problems solved by technology

However, its disadvantage is that both metal lithium negative electrode and sulfur-based positive electrode materials have poor cycle performance, which restricts the development of lithium-sulfur secondary batteries, which is also the focus of current research on lithium-sulfur secondary batteries.

For the sulfur-based positive electrode, the key problems are as follows: (1) Elemental sulfur is an electronic and ion insulator at room temperature, and a large amount of conductive agent (such as acetylene black) needs to be added when making the electrode, resulting in a decrease in the energy density of the electrode system; (2) ) Elemental sulfur will be reduced to easily soluble polysulfides during the discharge process, resulting in the loss of active materials, and polysulfides will increase the concentration of the electrolyte and deteriorate its ion conductivity after the polysulfides dissolve in the electrolyte; (3) The polysulfides in the electrolyte directly contact the metal lithium negative electrode, and a self-discharge reaction occurs; (4) the sulfur electrode will shrink and expand correspondingly during the charging and discharging process, which will destroy the physical structure of the electrode to a certain extent

These problems restrict the electrochemical performance of sulfur-based cathodes, resulting in low utilization of sulfur active materials, poor electrochemical reversibility, and fast capacity fading.

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