Core-shell structured Si-Li4Ti5O12 composite material

Abstract

The invention provides a preparation method of core-shell structured Si-Li4Ti5O12 composite material. The preparation method comprises preparing outer-layer spinning liquid by mixing lithium source, titanium source, organic acid, high-molecular polymer and absolute ethanol; preparing inner-layer spinning liquid by high-molecule polymer, high-capacity anode material and anhydrous ethanol; preparing the core-shell structured Si-Li4Ti5O12 composite material by electrospinning and calcination. With the coaxial electrospinning technology, the different materials can be jet out from the inner and outer layers of solution to prepare the composite material with the coaxial structure, and a nanometer composite material with high-capacity negative electrode material as the core and the zero-strain material as the shell is formed.

Description

technical field [0001] The invention relates to a lithium titanate material, in particular to the preparation of a core-shell structure Si-Li by using a coaxial electrospinning method 4 Ti 5 o 12 composite material. Background technique [0002] With the continuous update of battery electrode materials, there are more and more types of batteries. The traditional battery anode material is generally graphite, and its theoretical specific capacity can reach 372mAh / g. However, since the lithium intercalation potential of graphite materials is around 0.1v, an SEI film will be formed during the first charge and discharge process, and the loss of lithium is relatively serious, resulting in a rapid decline in capacity. In addition, since the graphite anode material has a hexagonal layered structure, the intercalation and extraction of lithium ions have a great influence on its structure. After 400 cycles, the volume expansion of the graphite negative electrode has brought safet...

AI Technical Summary

Problems solved by technology

However, lithium titanate itself also has shortcomings. Since lithium titanate itself can only accommodate 3 foreign lithium ions within the charge and discharge voltage range of 1-2.5V, its theoretical specific capacity is only 175mAh / g.

The low energy density has limited its application

[0004] Each negative electrode material has its own defects: graphite and silicon negative electrode materials mainly have low reversible capacity and volume expansion for the first time; lithium titanate negative electrode materials have low theoretical specific capacity

However, due to the electrostatic effect, the stability of the internal solution cannot be guaranteed, and the final fiber filament structure is very uneven.

Images