Electrochemical device and its preparation method and electronic device

Abstract

Embodiments of the present application provide electrochemical devices, methods of manufacturing the same, and electronic devices. The electrochemical device includes: a positive electrode sheet, including a positive electrode active material layer; a negative electrode sheet, including a negative electrode active material layer; a separator, arranged between the positive electrode sheet and the negative electrode sheet. Wherein, the mass ratio of fluorine element and sulfur element in the surface layer of the positive electrode active material layer is a, and the mass ratio of fluorine element and sulfur element in the surface layer of the negative electrode active material layer is b, 30≤a≤300, 5≤b≤50. The present application controls the mass ratio of the fluorine element and the sulfur element in the surface layer of the positive electrode active material layer and the negative electrode active material layer, so that a stable negative electrode solid electrolyte phase interface film (SEI) is formed on the negative electrode surface, and a stable positive electrode is formed on the positive electrode surface Solid electrolyte phase interface film (CEI), thereby improving the cycle performance of electrochemical devices.

Description

technical field [0001] The present application relates to the field of electronic technology, in particular to an electrochemical device, a preparation method thereof, and an electronic device. Background technique [0002] In recent years, with the rapid development of electronic products and electric vehicles, the requirements for the cycle performance of electrochemical devices (eg, lithium-ion batteries) are also increasing. Although various methods currently exist to improve the cycle performance of electrochemical devices, not all aspects are completely satisfactory, and further improvements in this regard are expected. Contents of the invention [0003] An embodiment of the present application provides an electrochemical device, comprising: a positive electrode sheet, the positive electrode sheet includes a positive active material layer; a negative electrode sheet, the negative electrode sheet includes a negative active material layer; a separator, the separator is...

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Problems solved by technology

Although various methods currently exist to improve the cycle performance of electrochemical devices, not all aspects are completely satisfactory, and further improvements in this area are expected

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