Preparation method of secondary battery

Abstract

The invention belongs to the technical field of batteries, and relates to a preparation method of a secondary battery, which comprises the following steps: assembling a first positive plate, a first diaphragm, a first negative plate, a first electrolyte and a first packaging shell to prepare a first battery; carrying out charge-discharge circulation on the first battery; then, disassembling the first battery, and taking out the first positive plate subjected to surface passivation treatment; obtaining a second positive plate, wherein the second positive plate comprises a second positive electrode material and a second positive electrode current collector, the second positive electrode material is the same as or different from the first positive electrode material, and the second positive electrode current collector is the first positive electrode current collector of which the surface is passivated; and assembling the second positive plate, a second diaphragm, a second negative plate,a second electrolyte and a second packaging shell, and preparing the secondary battery, wherein the second electrolyte comprises bis (fluorosulfonyl) imide salt and / or bis (trifluoromethylsulfonyl) imide salt. The secondary battery prepared by the preparation method disclosed by the invention can effectively inhibit corrosion of electrolyte containing FSI <-> and TFSI <-> to a positive electrode current collector.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a preparation method of a secondary battery. Background technique [0002] Lithium-ion batteries have been widely used in all aspects of life. As a typical secondary battery, lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, separators, and electrolytes. When charging, lithium ions are extracted from the positive electrode material and migrate to the negative electrode active material; when discharging, lithium ions are extracted from the negative electrode active material and return to the positive electrode. In the "rocking chair" working process of lithium-ion batteries, the electrolyte mainly plays the role of transporting ions. Traditional lithium-ion battery electrolytes usually use LiPF 6 As electrolyte salt and carbonates as solvent (concentration is 1mol / L). Although this electrolyte formula has been widely used in li...

AI Technical Summary

Problems solved by technology

However, the ultra-high concentration electrolyte often has a high viscosity, resulting in poor wettability of the electrode and limited battery charge and discharge rate performance; the hybridization of the electrolyte is usually difficult to achieve the effect of effectively passivating the positive metal current collector

Corrosion-resistant materials such as TiN, TiB 2 The stainless steel sheet treated with the same process has complicated process and high cost; and in the process of long cycle, the coating will still be obviously corroded

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