Electrochemical and electronic devices

Abstract

The present application provides electrochemical devices and electronic devices. The electrochemical device includes a positive pole piece, a negative pole piece, and a separator disposed 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 is provided on the surface of at least one side of the isolation membrane, and the protective coating includes a blocking agent; (b) the isolation membrane Including a blocking agent; (c) the negative electrode pole piece includes a negative electrode active material layer, and the surface of the negative electrode active material layer is provided with a protective coating; (d) the negative electrode active material layer includes core-shell structure particles, and the outer shell of the core-shell structure particles includes At least one of inorganic materials or polymers, and the core of the core-shell structured particle includes the blocking agent. The blocking agent includes at least one of red phosphorus, sulfur, iodine, or selenium. The embodiments of the present application can reduce the risk of lithium precipitation and improve the cycle performance and safety performance of the electrochemical device.

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 (eg, a lithium-ion battery) is charged at a high rate or at a low temperature, the negative electrode plate is prone to lithium deposition. Once lithium precipitation occurs, its reaction with the electrolyte will accelerate the degradation of the performance of the electrochemical device, and if the growing lithium dendrites pierce the isolation membrane, 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 or the like is arranged between the two separators to absorb part of th...

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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