Ion sieve cathode for electrolytic cell used for extracting lithium from lithium-containing aqueous solution and method for producing same

Abstract

The invention provides an ion sieve cathode for an electrolytic cell used for extracting lithium from a lithium-containing aqueous solution and a manufacturing method of the same. The manufacturing method comprises the following steps: uniformly mixing a conductive agent, lithium-intercalatable oxide and pre-lithiated polyphenylene sulfide or a pre-lithiated polyphenylene sulfide derivative in a mixer to obtain powder A; mixing polytetrafluoroethylene powder and the powder A in the mixer to obtain powder B; then carrying out grinding by using supersonic dry gas to extend and open a polytetrafluoroethylene molecular chain in the powder B and to allow the polytetrafluoroethylene molecular chain to form physical adhesion with carbon-based powder, thereby obtaining powder C; and preparing a cathode film D under high-temperature hot pressing, and thermally compounding the cathode film D on the two sides of a corrosion-resistant current collector by adopting a hot-pressing compounding process to prepare the ion sieve cathode. The prepared ion sieve cathode is large in active substance loading capacity, uniform and controllable in thickness, high in strength, good in corrosion resistance,high in conductivity and high in current efficiency; and a pre-lithiated polyphenylene sulfide-based ion sieve is introduced, so other alkali metals and alkaline-earth metals can be effectively prevented from entering crystal lattices of lithium-embedded oxide.

Description

technical field [0001] The invention relates to an ion sieve cathode for an electrolytic cell for extracting lithium in a lithium-containing aqueous solution and a manufacturing method thereof, belonging to the field of new energy materials. Background technique [0002] With the rapid development of mobile communications, electric vehicles, and the Internet of Things, the demand for lithium batteries continues to grow. At present, the global lithium battery-based lithium products consume ~300,000 tons of lithium annually, and the annual lithium consumption is 7% ~ 11%. The speed is increasing continuously and showing an exponential upward trend. However, the total amount of proven onshore lithium resources in the world is only 14 million tons, which is far from meeting the market demand for lithium in the future. Therefore, it is particularly important to effectively extract lithium from the treatment solution of lithium batteries and salt lake brine, and the amount of lit...

AI Technical Summary

Problems solved by technology

[0003] The core problem of extracting lithium from aqueous solution is how to effectively enrich lithium. The methods proposed by researchers include electrodialysis using Japanese monovalent cation exchange membrane (Chinese patent application number CN200310122238), phytic acid precipitation method (Chinese patent application No. CN201610853866), ion sieve capture method (Chinese patent application number CN201010555927), etc., wherein the method of combining electrodialysis and ion sieve is the most convenient (Chinese patent application number CN201110185128), and the cost is low, but the ion sieve in this method The manufacturing process follows the traditional wet pulping process and is coated on the surface of the corrosion-resistant current collector. This method cannot effectively increase the load on the surface of the current collector. The solvent evaporation process leads to loose coating, low electrical conductivity, and corrosion resistance It is easy to fall off in the flowing lithium-containing aqueous solution, and the service life is short

In addition, although the lithium intercalation oxide in the coating can effectively prevent the intercalation of alkaline earth metals (calcium and magnesium ions), it cannot prevent the electrochemical intercalation of alkali metals such as sodium and potassium. , it is more difficult to extract lithium

The researchers also proposed to use polyphenylene sulfide-based powders to prepare solid-state electrolytes and construct a lithium-ion conductive network in the cathode, which exhibits excellent lithium-ion conductivity at room temperature (Chinese patent application number CN201610511980), but this method also uses The traditional NMP wet coating process has the defects of high porosity, low conductivity, low loading capacity, and the inability to fully utilize the lithium ion conductivity of solid electrolytes.

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