A kind of negative electrode for lithium secondary battery and preparation method thereof and lithium secondary battery

Abstract

The invention provides a negative electrode for a lithium secondary battery, a preparation method thereof and a lithium secondary battery, and belongs to the field of chemical power sources. The negative electrode mainly consists of a convex array electrode skeleton, a nano-scale alloy skeleton and active metal lithium, the material of the large-aperture convex array electrode skeleton is any oneof Cu, Al, Sn, Fe, Co, Ni, Zn and In, the nano-scale alloy skeleton comprises a lithium element and a non-lithium element, the material of he the non-lithium element comprises at least one of Sn, Si,Cu, In, Al, Mg, Ge, Zn, Ni, the active metal lithium is filled in the pores of the nano-scale alloy skeleton and is fully contact with the nano-scale alloy skeleton to form a lithium-rich alloy, and the lithium-rich alloy is deposited in the pores of the convex array electrode skeleton. The negative electrode provided by the invention can prevent the collapse of the electrode due to the structuraldamage of the nano-scale skeleton in a long-term circulation process, fully inhibit the volume change of the electrode to improve the interface stability, and further improve the electrochemical performance of the lithium negative electrode.

Description

technical field [0001] The invention belongs to the field of chemical power sources; in particular, it relates to a negative electrode for a lithium secondary battery, a preparation method thereof and a lithium secondary battery. Background technique [0002] With the development of society, the demand for secondary battery systems with higher energy density is becoming increasingly urgent. Lithium metal has the highest specific capacity (3860mAh / g) and the most negative electrode potential (-3.045V vs. SHE) among the known negative electrode materials, but lithium metal is extremely prone to complex interfacial reactions with the electrolyte, resulting in active Lithium consumption, electrolyte drying up, and interface impedance gradually increase, and then the efficiency continues to decrease during the charge-discharge cycle; the uneven deposition of lithium ions on the electrode surface leads to a large number of lithium dendrites on the electrode surface, and the contin...

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Problems solved by technology

Kozen et al. used atomic layer deposition (ALD) to form a 14nm thick Al on the surface of the lithium negative electrode. 2 o 3 film, inhibiting interfacial side reactions and lithium dendrite growth, but these methods are complex to prepare and costly

[0004] In the patent with the application number CN 201510394325.7, lithium metal powder is used as the negative electrode. The powder porous electrode has a high specific surface area, which reduces the current density and inhibits the growth of lithium dendrites. Reduced cycle stability

In US 4002492, it is proposed to use Li-Al alloy as the negative electrode, and some people use Li-Sn, Li-Si alloy as the negative electrode to reduce the reactivity of the negative electrode and inhibit the growth of lithium dendrites, but the electrode volume changes drastically during the alloying-dealloying process , leading to electrode pulverization and short battery life

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