A secondary battery and electrical device

Abstract

The invention provides a secondary battery and an electrical device. A sodium supplement source is added to the sodium ion secondary battery, and the sodium supplement source is used to supplement the sodium ion battery due to the formation of negative electrode SEI film and irreversible compounds during the first charge and discharge Consume a part of active sodium, and further limit the residual sodium content W of the negative electrode sheet in the sodium-replenishing secondary battery R , the W R The design is within the scope of the present invention, avoiding the impact on the comprehensive performance of the battery caused by too much or too little sodium supplementation, so that the added sodium can directly supplement the negative electrode SEI film and irreversible compounds formed in the first charge and discharge process of the battery. The consumed active sodium makes up for the capacity consumption of the material for the first charge and discharge, thus obtaining a sodium-supplemented secondary battery with better comprehensive performance, and improving the first Coulombic efficiency, cycle performance, and storage performance of the battery.

Description

technical field [0001] The invention relates to the field of sodium ion batteries, in particular to a secondary battery and an electrical device. Background technique [0002] The working principle of sodium ion battery is similar to that of lithium ion battery, which uses the process of insertion and extraction of sodium ions between the positive and negative electrodes to realize charge and discharge. Compared with conventional cathode materials for lithium-ion batteries, sodium-ion cathode materials have the advantages of abundant reserves, easy availability of raw materials, and low cost, which make sodium-ion batteries attract much attention. [0003] But at the same time, the sodium-ion battery also has the same problem as the lithium-ion battery, that is, when it is charged for the first time, it will form an SEI film on the surface of the negative electrode, consume a part of the sodium ions, and reduce the reversible capacity of the positive electrode; at the same t...

AI Technical Summary

Problems solved by technology

[0005] One of the objectives of the present invention is to provide a secondary battery to solve the problem that the current sodium ion battery consumes a part of the active sodium due to the formation of the negative electrode SEI film and irreversible compounds during the first charge and discharge process, resulting in a decrease in battery capacity.

Images