Preparing method of electrolyte for lithium thionyl chloride cell

Abstract

The present invention is improved preparation process of electrolyte for lithium thionyl chloride. The SOCl2 solution is first rectified, then added with LiAlCl4 and metal lithium and heated and reflux purified for at least 12 hr, SO2 gas is injected into the solution, and in dry environment, the solution is filtered to prepare the electrolyte. The electrolyte has raised purity and can improve the voltage lag state of the lithium cell effectively.

Description

technical field [0001] The present invention relates to the field of electrochemistry, more specifically, it relates to the improvement of the electrolyte preparation method of lithium thionyl chloride battery (referred to as lithium sub-battery). Background technique [0002] Lithium sub-battery is a kind of battery with the highest specific energy in the actual application battery in the world at present, and it adopts liquid negative electrode, namely electrolyte solution described in the present invention. A characteristic of lithium sub-batteries is that the reaction product lithium chloride will adhere to the cathode to form a dense passivation film, thereby preventing the battery reaction from continuing. Under normal discharge current, this film can be easily broken down by the current, but when the battery is under low-current discharge or storage, the film will continue to thicken, and when a large current is required to work, the battery will not work normally. T...

AI Technical Summary

Problems solved by technology

[0003] The preparation method of existing lithium sub-battery electrolyte solution mostly is to use LiAlCl 4 (Lithium chloride aluminum salt) dissolved in SOCl according to the specified concentration 2 (thionyl chloride) to prepare the solution, and then adopt the heating and reflux mode to remove water, because this method does not have the electrode raw material LiAlCl 4 After processing, the heavy metal content in the final electrolyte is high, which leads to an increase in side reactions of the battery, so that the battery power cannot be effectively released, and the generation of battery hysteresis is aggravated

Chinese patent application, publication number CN1508900A, published on June 30, 2004, the name of the invention is "LiAlCl for lithium battery 4 / SOCl 2 Electrolyte preparation method", the patent application proposes to add LiAlCl to LiAlCl in a closed and dry environment 4 / SOCl 2 A preparation method in which a reaction amount of lithium metal is added to the solution and stirred until the solution is free of gas. This method can effectively reduce the water content in the solution, but its disadvantage is that the heavy metal impurities in the solution cannot be effectively removed, and the lithium sub-battery voltage The phenomenon of lagging has not improved