Positive electrode and preparation method therefor, and lithium secondary battery

Abstract

The invention discloses a positive electrode and a preparation method therefor, and a lithium secondary battery employing the positive electrode. The positive electrode comprises a conductive substrate, a positive electrode active material layer and a lithium-compensating layer which is arranged between the conductive substrate and the positive electrode active material layer; the lithium-compensating layer comprises at least a kind of lithium-containing compound, at least a kind of conductive agent and at least a kind of binder; the lithium-containing compound is chosen from the group formed by the compound as shown in the formula Li<x>A, wherein A is O, P, S or N; and x is greater than 0 and less than or equal to 3. The positive electrode provided by the invention has the lithium-compensating function, and is capable of effectively compensating the irreversible capacity loss of the lithium secondary ion in the charging-discharging process and improving the energy density of the battery; the lithium secondary ion has excellent cycling performance and high-rate discharging performance; the positive electrode provided by the invention does not require metal lithium; compared with the battery adopting metal lithium, the severity on the operating environment and operation process is lowered; and therefore, the positive electrode provided by the invention can be prepared by a conventional process under conventional conditions.

Description

technical field

[0001] The invention relates to a positive electrode and a preparation method thereof, and also relates to a lithium secondary battery using the positive electrode. Background technique

[0002] Lithium secondary batteries using non-aqueous electrolytes have the advantages of high specific energy and low environmental pollution. Since Japan's Sony Corporation first launched commercial lithium secondary batteries in 1990, lithium secondary batteries have been widely used in electronic consumer products such as mobile phones, portable computers, and video cameras. With the continuous development of electronic product technologies such as smartphones and notebook computers, the energy density requirements for lithium secondary batteries are getting higher and higher.

[0003] As we all know, for non-aqueous electrolyte lithium secondary batteries, during the first charge and discharge process of the battery, due to the formation of a solid electrolyte (ie, SEI ...

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