A high-energy silicon-containing lithium battery and a preparation method thereof-

Abstract

The invention discloses a high-energy silicon-containing lithium battery, wherein the conductive agent of the positive electrode is 0.02-0.06% single-walled carbon nanotubes and 0.2-0.6% graphene: Thenegative electrode sheet is made of the following ingredients in parts by weight: up to 100% of the negative electrode active material, 0-1% of conductive carbon black, 0.02-0.08% of single-walled carbon nanotubes, 1-2% of CMC and 1.2-2.5% of binder; The negative electrode active material is carbon silicon and / or oxygen silicon, and the gram capacity is more than or equal to 650 mAh / g; The binderis prepared from styrene-butadiene rubber, acrylic acid and PMMA in 5-7: 1: 2-4 by weight ratio. The high-energy silicon-containing lithium battery has better charging and discharging stability, volume expansion resistance, cycle performance and stability under the premise of high energy by optimizing the conductive agent composition of the positive and negative electrodes and optimizing the binder.

Description

Technical field [0001] The invention relates to the technical field of secondary batteries, in particular to a high-energy silicon-containing lithium battery and a preparation method. Background technique [0002] With the development of mobile electronic devices, the demand for batteries is increasing, and higher requirements are put forward for the capacity, voltage and service life of the batteries. Lithium ion battery is a kind of secondary battery (rechargeable battery), which mainly relies on the movement of lithium ions between positive and negative electrodes to work. [0003] The 18650 lithium-ion battery is a standard lithium-ion battery model first developed by Japan’s SONY, which is a lithium-ion secondary battery. Wherein 18 means the diameter is 18mm, 65 means the length is 65mm, and 0 means cylindrical battery. 18650 lithium ion battery products are used in 3C (computer, communications, consumer electronics) electronic products such as notebook power supplies and m...

AI Technical Summary

Problems solved by technology

[0004] Lithium-ion batteries on the market have many disadvantages such as poor safety performance, low capacity, low capacity per unit volume, low power, and poor cycle performance.

Secondly, the positive electrode materials lithium manganese oxide and lithium iron phosphate of the existing 18650 lithium-ion battery have low specific energy, and the positive electrode material lithium cobalt oxide is expensive. The thickening of the material leads to unstable density of the coating surface, which leads to various problems, such as the qualified rate of the produced products is lower than 90%, the safety performance of the product is poor, the thermal stability of the battery is poor, and the internal short circuit is easy to thermal diffusion and explosion. Fire, cycle performance 0.5C / 0.5C charge and discharge is less than 300 cycles, low power performance, low battery discharge platform is 3.6V and other shortcomings

[0005] Silicon carbon or silicon oxygen, as the negative electrode material of lithium battery, has high battery-specific capacity. However, compared with traditional negative electrode active materials, silicon-containing negative electrode materials often suffer from larger bulk capacity during charging and discharging. Changes, resulting in damage to the silicon structure and continued side reactions, reducing the cycle life of the battery

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