Lithium sulfur battery

Abstract

A lithium sulphur battery comprises an anode including an anode collector and an anode active material selected from the group consisting of metallic lithium, a lithium alloy and a lithium-carbon system; a cathode including a cathode collector and a cathode active material in the form of a sulphur-containing nanostructure including at least one of the group consisting of sulphur, an organosulphur compound, an organosulphur polymer, a carbon-sulfur composite, a sulphur-polymer composite and an organic sulfide; an electrolyte including a lithium salt electrolyte and a mixed organic solvent; and a separator disposed between the cathode and the anode for separating the electrolyte into a cathode electrolyte and an anode electrolyte and for allowing lithium ions to pass through. The cathode active material can prevent dissolution of intermediate polysulphides from the cathode and thereby enhance the battery life and power density.

Description

technical field [0001] The invention relates to a lithium-sulfur battery, in particular to a lithium-sulfur battery with high energy density. Background technique [0002] With the gradual depletion of oil, the global impact of a large number of vehicles and their pollution, there is growing interest in providing safe, inexpensive, high energy density, and long-life rechargeable batteries for electric devices and vehicles. Rechargeable lithium batteries have the highest energy density of all batteries and have become the energy storage unit for most mobile electronics today. Although most electronic devices only require moderate charging and discharging speeds, some new applications, such as regenerative braking of hybrid electric vehicles, energy backup, and portable electric tools, require batteries with high energy density and high power at the same time. This is still difficult to achieve for the current lithium battery. A good lithium battery requires battery material...

AI Technical Summary

Problems solved by technology

[0006] Second, the anions of polysulfide intermediates formed during charge and discharge are highly soluble in polar organic solvents, and these anions can permeate through the separator to reach the anode and produce precipitates at the anode (Li 2 S 2 and Li 2 S), in the process of repeated charging and discharging of the battery, it leads to a decrease in the capacity of the battery

During the discharge process, the expansion and accumulation of solid precipitates on the surface of the cathode can also lead to irreversible electrochemical reactions, which in turn lead to mass loss of active materials.

[0007] Third, in the process of cyclic charging and discharging, dendrites will gradually grow on the lithium electrode, and the dendrites will continue to grow and extend, and finally pass through the electrolyte to reach the cathode, which may cause an internal short circuit of the battery, which is very dangerous. Therefore, the cycle charge and discharge life of this battery is only a few times.

Although some organosulfur polymers, such as DMcT (2,5-dimercapto-1,3,4-thiadiazide), showed relatively good performance in terms of power density and cycle life, their charge density decrease was particularly pronounced, Almost less than 40% of the theoretical charge, even at relatively high temperatures

Although existing reports have shown that carbon-sulfur composites or conductive polymer-sulfur composites have not greatly improved the available power and cycle life

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