Electrochemical device and electronic device

Abstract

The invention provides an electrochemical device and an electronic device. The electrochemical device comprises a positive pole piece, a negative pole piece and an isolating membrane arranged between the positive pole piece and the negative pole piece. The electrochemical device satisfies at least one of the following conditions (a)-(d): (a) a protective coating layer is provided on the surface of at least one side of the separator, the protective coating layer including a blocking agent; (b) the isolating membrane comprises a blocking agent; (c) the negative pole piece comprises a negative active material layer, and a protective coating is arranged on the surface of the negative active material layer; (d) the negative electrode active material layer comprises core-shell structure particles, the shells of the core-shell structure particles comprise at least one of an inorganic material or a polymer, and the cores of the core-shell structure particles comprise the blocking agent. The blocking agent comprises at least one of red phosphorus, sulfur, iodine or selenium. According to the embodiment of the invention, the lithium precipitation risk can be reduced, and the cycle performance and safety performance of the electrochemical device are improved.

Description

technical field [0001] The present application relates to the field of electrochemical energy storage, in particular to electrochemical devices and electronic devices. Background technique [0002] When an electrochemical device (for example, a lithium-ion battery) is charged at a high rate or at a low temperature, the negative electrode sheet is prone to lithium precipitation. Once lithium precipitation occurs, its reaction with the electrolyte will accelerate the attenuation of the performance of the electrochemical device, and if the growing lithium dendrites pierce the separator, it will cause an internal short circuit in the electrochemical device, which may easily lead to accidents such as fire and explosion. In order to alleviate the influence of lithium dendrites, two layers of separators can be used between the positive electrode and the negative electrode, and an absorbing layer including graphite is arranged between the two layers of separators to absorb part of t...

AI Technical Summary

Problems solved by technology

However, setting graphite between two layers of separator will reduce the electrical insulation capacity of the separator and increase the risk of short circuit, and materials such as graphite that deintercalate lithium ions have a small lithium storage capacity, making it difficult to completely absorb the generated lithium metal; in addition, The thickness of the sandwich structure is relatively large, which is not conducive to the improvement of the energy density of the electrochemical device.

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