Preparation method of complex lithium negative pole of solid state battery

Abstract

The present invention discloses a preparation method of a complex lithium negative pole of a solid state battery, and belongs to the technical field of electrochemistry and new energy resources. The preparation method mainly comprises the steps: depositing lithium metal on three-dimensional carbon material or foam porous material gaps by using a heat infusing melting method or an electrodeposition method to obtain the complex lithium negative pole, wherein the application of a three-dimensional framework plays two roles, namely, providing adequate space for pre-storing lithium in the preparation process; providing a carrier for receiving metal lithium in a battery circulation process. The complex lithium negative pole can be widely applied in lithium metal batteries such as lithium ion batteries, lithium-air batteries, lithium-sulfur batteries, and solid state batteries. In the assembled symmetric solid state battery, under large electric current density of 5mA cm-2, a stable voltage decay (200mV) can still be kept after circulation for 100 times, in the battery circulation, the growth of lithium dendrites can be inhibited and the pole volume change can be stabilized, and the advantages of being good in circulation stability, and long service life can be realized; in the present invention, a carrier material is rich, and low in price; the process is controlled, the cost is low, and the batch production can be realized.

Description

technical field [0001] The invention discloses a method for preparing a composite lithium negative electrode for a solid-state battery. Lithium metal is deposited in the voids of a three-dimensional carbon material or a porous foam material by heat infusion melting or electrodeposition to prepare a composite lithium negative electrode, which belongs to electrochemical and new energy materials technology field, especially related to the preparation of composite lithium negative electrode materials for solid-state batteries. Background technique [0002] In recent years, with the rapid development of industries such as electronics, information and new energy vehicles, new energy storage devices have become the focus of scientific and technological development, and the research and development of high-performance and large-capacity lithium-ion batteries has become the current new energy and Research hotspots in the field of materials. Due to many advantages such as high energy...

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Problems solved by technology

[0003] However, lithium metal dendrites are easily formed during charging and discharging of lithium metal batteries and cause electrode volume changes.

Existing studies have found that when lithium metal foil is used as the negative electrode of lithium batteries, as the number of cycles increases, lithium dendrites gradually form on the surface, and the larger specific surface of the dendrites consumes part of the lithium and electrolyte, and the dendrites continue to grow. The formation of dead lithium, the accumulation of dendrites and dead lithium leads to changes in the volume of the electrode, resulting in a decrease in the coulombic efficiency of the electrode cycle, and even an internal short circuit, battery thermal failure or explosion, causing safety issues in the use of lithium metal (Energy Environ.Sci ., 2013, 7, 513–537.)

For many years, the problem of lithium dendrites and volume changes in lithium metal has not been effectively solved

Recently, Cui Yi's research group reported a method to prepare lithium metal anodes by infusing hot molten metal lithium into the carrier gap. This method has the characteristics of simple, efficient and controllable preparation, but the wettability of molten liquid lithium metal is poor. The high temperature environment hinders the application of most carriers. The two reported carriers are mainly layered graphene oxide and surface-modified framework materials (Nat.Nanotechnol., 2016, 11, 575–652; Nat.Commun., 2016,7,10992; Proc.Natl.Acad.Sci.USA,2016,113,2862–2867.), and using three-dimensional carbon materials or foam porous materials as carriers to prepare lithium metal electrodes in the hot melt infusion method has not yet been to report

In addition, the deposition of lithium metal into the voids of three-dimensional carbon materials (carbon felt, carbon paper, carbon cloth) or foamed porous materials (copper foam and carbon foam) by electrodeposition has not been reported yet.

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