Sulphidepolymer coated sulfur / carbon composite material and preparation method thereof

Abstract

A sulfide polymer coated sulfur / carbon composite material and a preparation method thereof. The composite material includes composite containing carbon with high surface area and sulfur and a sulfide polymer cladding layer. The preparation method is as below: conducting ball-milling on sulfur and carbon with high surface area in a ball mill and conducting heat treatment on the product under protective atmosphere; dispersing the product in a solution containing polymer monomers and adding a initiator to initiate polymerization; filtering, washing and drying; and conducting heat treatment on the product under protective atmosphere, so as to obtain the sulfide polymer coated sulfur / carbon composite material. The composite material provided by the invention as an anode material for lithium sulfur battery has the following advantages: high surface area carbon material can improve the electronic conductivity of sulfur, and inhibit polysulfide erosion; the sulfide polymer coating layer not only inhibits the loss of polysulfide but also provides part of the capacity. Lithium sulfur battery composed of the composite material has the advantages of high specific capacity, long service life, high rate capability, simple preparation and low cost, and has good application prospect.

Description

technical field [0001] The invention belongs to the field of secondary lithium batteries, and in particular relates to a sulfur / carbon composite material coated with a vulcanized polymer and a preparation method thereof. Background technique [0002] Among commercialized secondary batteries, lithium-ion secondary batteries have the highest specific energy, specific power and good cycle life, and have been widely used in portable electronic devices, backup power supplies, uninterruptible power supplies and other fields, as well as electric vehicles and The first choice for energy storage batteries. [0003] With the deteriorating energy and environmental problems and the development of science and technology, electric vehicles and advanced portable electronic communication devices have put forward higher requirements on the specific energy of the secondary batteries used. For example, the specific energy of power batteries required for pure electric vehicles should be at lea...

AI Technical Summary

Problems solved by technology

Although a variety of carbon materials or conductive polymers have been applied to the development of sulfur / carbon or polymer / sulfur composite materials, and to a certain extent, the electrochemical performance and cycle stability of the material have been improved, but there are still their own shortcomings. For example, the sulfur in the micropores of the sulfur-carbon composite has a high utilization rate, but the sulfur loading of the microporous carbon material is lower than 42%, and the performance of the material decreases with the increase of the sulfur loading. However, with the increase of the pore size or the use of graphite Although the sulfur loading capacity increases, the cycle performance of the composite material is not ideal.

Although vulcanized polymers have high cycle stability, their rate performance and sulfur loading are low. The above strategies cannot fully meet the requirements of Li-S batteries.