Li-S battery and Li-S reserve battery capable of performing impulsive discharge, and preparation methods thereof

Abstract

The invention discloses a Li-S battery capable of performing impulsive discharge. The Li-S battery comprises electrolyte, and a battery cell comprising an anode component, a cathode component and a composite membrane, wherein the composite membrane mainly comprises a base membrane and a coating layer, coated on the base membrane, with single lithium-ion permeability; perfluoro lithium sulfonamide polymer electrolyte in the coating layer adopts a perfluoro carbon chain as a main chain, and a side chain contains Si-O or C-O repetitive units and fixed large anion end groups. The invention further discloses a Li-S reserve battery capable of performing impulsive discharge. The Li-S reserve battery mainly adopts the structure that a vesicle type electrolyte storage structure is added on the basis of the Li-S battery. The preparation method of the Li-S battery comprises firstly preparing a cathode plate, preparing a composite membrane, activating the composite membrane, then preparing a battery cell, and finally assembling the composite membrane and the battery cell, so as to obtain the Li-S reserve battery. The Li-S battery, the Li-S reserve battery and the preparation methods thereof have the advantages that the product circularity is good, the energy density is high, high-rate discharge can be performed, and the rate capability is good.

Description

technical field [0001] The invention relates to a lithium-sulfur battery and a preparation method thereof, in particular to a Li-S reserve battery and a preparation method thereof. Background technique [0002] The theoretical energy density of the Li-S battery system based on lithium metal anode and sulfur element cathode is 2600Wh / kg and 2800Wh / L, and the average voltage is 2.1V. Compared with the theoretical energy density of lithium-ion batteries of 580Wh / kg and TNT equivalent of 1280Wh / kg, the Li-S battery system has a rather high energy density. Assuming that 25% of the theoretical value can be realized on the actual battery, the energy density of the Li-S battery system is about 700Wh / kg, which is 4 times that of the existing lithium-ion battery. So far, the application potential of Li-S battery system has been confirmed by the studies of several research groups. [0003] Unlike ordinary lithium-ion batteries, lithium-sulfur batteries are in a charged state after be...

AI Technical Summary

Problems solved by technology

However, in the lithium-sulfur secondary battery system, since the elemental sulfur is an insulator, the polysulfide lithium produced by the electrochemical process is also an electronic insulator. In addition, the electrochemical process of the lithium-sulfur battery itself has its own particularity, which is manifested in two aspects. , one is that the electrochemical process is accompanied by a complex phase transition process, and the other is that the kinetic process during discharge is complex, which is divided into three processes: high-speed, medium-speed and low-speed kinetics. Therefore, the current development of the battery system is to fully reflect the high power density. Advantages, it is necessary to comprehensively consider the sulfur cathode design, electrolyte preparation and battery structure to improve the pulse and rate discharge characteristics of the battery

[0005] In the lithium-ion battery system using ordinary separators and electrolytes, during the charge and discharge process, because the anions do not participate in the electrode reaction, they gather at the electrode / electrolyte interface, which will hinder the migration of cations, thereby reducing the current density and affecting the energy efficiency and service life of the battery. , especially when high current discharge will cause more serious problems

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