A method for preparing conductive fiber paper with a lithium-philic-phobic gradient structure and conductive fiber paper

Abstract

The present invention provides a method and a conductive fiber paper for preparing conductive fiber paper with a lithium-phobic gradient structure. The preparation of conductive fiber paper needs to use atomic layer deposition method to form a lithiophilic coating layer on the surface of carbon nanotubes, and then use a wet papermaking process to form a film by gradient paper according to different ratios of lithiophilic materials. The invention also provides a method for preparing a composite metal lithium negative electrode, wherein the solid lithium is heated to a molten state, and then the lithium in the molten state at a high temperature is injected into the lithiophilic layer. The present invention also provides that a LiF protective layer is formed on the surface of the composite metal lithium negative electrode by atomic layer deposition or HF fluorination. The lithophilicity of the conductive fiber paper formed by the invention gradually weakens from the bottom layer to the top layer, and the top layer is completely lithophobic, which is conducive to the uniform deposition of metal lithium from the bottom layer to the top layer, thereby solving the problem of metal lithium deposition on the top layer, and significantly improving the lithium metal negative electrode. cycle stability and cycle life.

Description

technical field [0001] The invention belongs to the technical field of secondary batteries, and in particular relates to a method for preparing conductive fiber paper with a lithium-philic-phobic gradient structure and the conductive fiber paper. Background technique [0002] Since the 21st century, mobile electronic information products have developed rapidly, and the capacity requirements of energy storage batteries have become increasingly stringent. The energy density of traditional lithium-ion batteries is close to the upper limit, which is difficult to meet the needs of 3C products. Lithium metal anodes have attracted widespread attention due to their ultra-high specific capacity of 3860 mAh / g and the lowest reduction potential of -3.04 V. However, the metal lithium anode has been difficult to apply in practice so far, mainly due to the problems of dendrite growth and low Coulomb efficiency during the battery cycle: on the one hand, the deposition of lithium ions is gr...

AI Technical Summary

Problems solved by technology

However, metal lithium anodes have been difficult to be applied in practice so far, mainly because of the problems of dendrite growth and low Coulombic efficiency during the battery cycle: on the one hand, lithium ion deposition is greatly affected by the current density, the larger the current, the more lithium ion deposition Faster, the more conducive to the growth of dendrites, until it pierces the separator to cause an internal short circuit in the battery, there is a danger of battery combustion explosion; on the other hand, lithium metal has strong chemical activity, and will continue to have side reactions with the electrolyte, resulting in low Coulombic efficiency

In addition, metal foam or carbon fiber is relatively hard, which is easy to pierce the separator and cause a short circuit of the battery, which poses a potential safety risk

Images