An all-solid-state lithium-sulfur battery

Abstract

The invention discloses an all-solid-state lithium-sulfur battery, comprising a sulfur positive electrode, a lithium or lithium alloy negative electrode, and a lithiated sulfonic acid polymer solid electrolyte diaphragm; the solid electrolyte diaphragm is located between the sulfur positive electrode and the lithium or lithium alloy negative electrode; the sulfur positive electrode Including sulfur-containing active material, conductive agent and lithiated sulfonic acid polymer; sulfur positive electrode, lithiated sulfonic acid polymer solid electrolyte, lithium or lithium alloy negative electrode are sequentially stacked and assembled to form a battery. The room temperature ionic conductivity of the lithiated sulfonic acid polymer solid electrolyte is >10 ‑5 S / cm, no complex lithium salt is required, the preparation method is simple, and the room temperature ionic conductivity of the lithiated sulfonic acid polymer solid electrolyte is better than that of general inorganic-organic composite solid electrolytes. The polymer emulsion is used to prepare the sulfur positive electrode sheet, and an efficient "sulfur / carbon / solid electrolyte" interface is built inside the electrode to improve the activity of the sulfur electrode and obtain a battery with excellent performance; and the existing electrode sheet coating process and equipment, which is conducive to large-scale production.

Description

technical field [0001] The invention relates to a lithiated sulfonic acid polymer solid electrolyte, a preparation method thereof, and an all-solid lithium-sulfur battery. Background technique [0002] Lithium-sulfur batteries have become the next generation of secondary battery systems due to their high energy density and low cost. However, most of the lithium-sulfur batteries reported at present use organic electrolytes with low boiling points, and there are still some technical problems that need to be solved urgently. 1. Polysulfide, the discharge intermediate product of the sulfur positive electrode, dissolves in the electrolyte, which on the one hand causes the shuttle effect and reduces the Coulombic efficiency; on the other hand, the polysulfide diffuses through the separator to the negative electrode and corrodes metal lithium. 2. In a battery using an organic electrolyte, due to the uneven deposition of lithium ions, dendrites are easily formed on the metal lithiu...

AI Technical Summary

Problems solved by technology

1. Polysulfides, the discharge intermediate products of the sulfur positive electrode, dissolve in the electrolyte, which on the one hand causes the shuttle effect and reduces the Coulombic efficiency; on the other hand, the polysulfides diffuse through the diaphragm to the negative electrode, corroding metal lithium

2. In batteries using organic electrolytes, due to the uneven deposition of lithium ions, dendrites are easily formed on the metal lithium negative electrode. On the one hand, dead lithium affects the cycle performance of the battery; on the other hand, the dendrites penetrate the separator and cause a short circuit of the battery

3. The boiling point of the organic electrolyte is low. In the case of abuse, such as overcharging, over-discharging, and acupuncture batteries with external force, it will cause dangerous accidents such as combustion and explosion of the battery

[0004] The reported lithium-sulfur batteries or lithium-sulfur flow batteries all have one or more of the following defects: organic-inorganic composite solid electrolytes have low room temperature ionic conductivity; It is difficult to prepare; the interface contact resistance with the positive and negative electrodes is large; the inorganic solid electrolyte is brittle and fragile, and it is not easy to form; the preparation steps are cumbersome and not suitable for large-scale production

[0006] All-solid-state lithium-sulfur batteries using lithiated sulfonic acid polymer solid electrolytes have not been reported

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