Three-dimensional porous material containing lithium alloy skeleton network and preparation method thereof, and composite lithium negative electrode material and a preparation method thereof

Abstract

The invention discloses a three-dimensional porous material containing a lithium alloy skeleton network and a preparation method thereof, and a composite lithium negative electrode material of the three-dimensional porous material and a preparation method thereof. According to the invention, the phase separation or component segregation process of the high-temperature molten lithium-rich alloy in the three-dimensional porous material and / or on the surface of the three-dimensional porous material is controlled, the micro-nano three-dimensional lithium alloy skeleton network further divides pores of the porous material into small pores which are smaller in size and communicated with one another, and the lithium alloy micro-nano skeleton does not participate in a charge-discharge reaction; only the effects of enlarging the specific surface area, inducing uniform deposition of lithium ions and inhibiting formation of lithium dendrites are achieved, a multi-scale skeleton structure is formed with the three-dimensional porous base material, and the electrochemical performance of the negative electrode is further improved through the synergistic effect. The lithium alloy skeleton or the surface of the lithium alloy skeleton is filled with the metal lithium to form the composite lithium negative electrode material containing the lithium alloy skeleton network, which is formed by compounding lithium, the lithium alloy skeleton and the three-dimensional porous material, and the metal lithium provides reversible capacity for the charge-discharge reaction of the battery.

Description

technical field [0001] The invention belongs to the technical field of chemical power sources, and in particular relates to a three-dimensional porous material containing a lithium alloy skeleton network, its composite lithium negative electrode material and a preparation method. Background technique [0002] Lithium-ion batteries (LIBs) have become very popular energy storage devices at present. However, lithium-ion batteries use carbon as the negative electrode, and their theoretical specific capacity is only 372mAh / g, which has been difficult to meet the growing demand for high energy density energy storage. Lithium metal is considered to be the best choice for the anode material of next-generation lithium secondary batteries because of its high theoretical specific capacity (3860mAh / g) and the lowest electrochemical potential (-3.04V relative to the standard hydrogen electrode). However, the uncontrollable dendrite growth and "infinite" volume change of Li metal during ...

AI Technical Summary

Problems solved by technology

However, most commercially available three-dimensional porous materials have relatively large pore sizes, usually on the order of hundreds of microns, and relatively small specific surface areas.

On the one hand, the size and thickness of the deposited metal lithium are too large, which exceeds the effective distance of the skeleton induction effect. Therefore, the effect of ordinary porous materials acting as a three-dimensional skeleton to induce lithium nucleation and growth is limited. During the dissolution process, these large pores in these common porous substrates have very limited modulation on the nucleation and growth process of metal lithium; on the other hand, the larger size of the pores also leads to a smaller increase in the real electrochemical reaction area of ​​the negative electrode. , lithium dendrites are still prone to appear during high-rate charge and discharge, which is difficult to meet the needs of practical applications

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