A flexible self-supporting negative electrode material supported by carbon fiber lithium titanate nanosheets and its preparation method

Abstract

The invention discloses a flexible self-support negative electrode material with a carbon fiber-loaded lithium titanate nanosheet and a preparation method of the flexible self-support negative electrode material. The method comprises the following specific steps of dissolving butyl titanate or titanium isopropylate, lithium hydroxide and hydrogen peroxide into deionized water and then transferring the mixture to a polytetrafluoroethylene container; putting burnt and degummed carbon fiber cloth into the polytetrafluoroethylene container and reacting at 140-160 DEG C in a closed environment for 4-8 hours; taking out the carbon fiber cloth, washing the carbon fiber cloth by using the deionized water, drying the carbon fiber cloth; and carrying out thermal treatment at 500-700 DEG C under inert gas protection or a vacuum condition for 3-5 hours. The invention further provides a battery of using the flexible self-support negative electrode material. According to the flexible self-support negative electrode material, a metal current collector, a conductive additive and a binder used in a conventional preparation process of a negative electrode of a lithium-ion battery do not need to be used, and the operation is simple; the flexible self-support negative electrode material has good conductivity and ionic conductivity, and relatively high battery specific capacity and rate capability; and meanwhile, the flexible self-support negative electrode material can be arbitrarily bended, folded and stretched.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a carbon fiber-loaded lithium titanate nanosheet flexible self-supporting negative electrode material and a preparation method thereof. Background technique [0002] Spinel lithium titanate (Li 4 Ti 5 o 12 ) has the advantages of stable voltage platform, long cycle life, "zero strain" and high safety. It is an ideal lithium-ion battery anode material and has been used by many domestic and foreign manufacturers to develop commercial lithium-ion batteries. However, being a poor conductor of electrons, pure Li 4 Ti 5 o 12 Poor electrical conductivity and poor rate performance limit its application. [0003] Element doping, carbon coating or organic compounding of lithium titanate with carbon materials can effectively improve its rate performance. For example, using natural graphite, acetylene black, activated carbon, and carbon-containing polymers as carbon sources, high-energy ball ...

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Problems solved by technology

However, the final product obtained by the above method is still active material powder. In the subsequent battery production process, complex process steps such as slurry mixing, coating, cutting and other processes are still required to make electrode sheets, and metal current collectors, conductive additives and binder, which increases the cost of the battery

In recent years, it has been reported that electrode active materials can be loaded on conductive graphene paper or carbon fiber cloth, and the whole can be used as a flexible self-supporting electrode, thereby avoiding the use of metal current collectors, conductive additives and binders, and tedious electrode manufacturing processes. However, the uniform loading of active materials on such conductive substrates and the high cost are still not well resolved.

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