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

Abstract

The invention discloses a three-dimensional porous material containing a lithium alloy skeleton network, its composite lithium negative electrode material and a preparation method. The invention controls the phase separation or component segregation process of the high-temperature molten lithium-rich alloy inside and / or on the surface of the three-dimensional porous material, and the micro-nano-sized three-dimensional lithium alloy skeleton network further divides the pores of the porous material into smaller sizes and interpenetration The micro-nano-skeleton of lithium alloy does not participate in the charge-discharge reaction, but only expands the specific surface area, induces the uniform deposition of lithium ions, and inhibits the formation of lithium dendrites. It forms a multi-scale skeleton structure with the three-dimensional porous substrate and synergizes Further improve the electrochemical performance of the negative electrode. Lithium metal is filled in or on the surface of the lithium alloy skeleton to form lithium, lithium alloy skeleton, and three-dimensional porous material, which is a composite lithium anode material containing lithium alloy skeleton network, in which metal lithium provides the reversible capacity of the battery charge and discharge reaction .

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, a composite lithium negative electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries (LIBs) have now become very popular energy storage devices. However, the lithium-ion battery uses carbon as the negative electrode, and its theoretical specific capacity is only 372mAh / g, which has been difficult to meet the increasing demand for high energy density energy storage. Metal lithium is considered to be the best choice for next-generation lithium secondary battery anode materials due to its high theoretical specific capacity (3860 mAh / g) and the lowest electrochemical potential (-3.04 V relative to standard hydrogen electrodes). However, the uncontrollable dendrite growth and “infinite” volume change of metallic lithium during cy...

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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