Studies On Synthesis,preparation Technology And Electrochemical Performance Of TiO₂ As Anode Material For Lithium Ion Batteries

The widespread use of electric energy benefits from people’s increasing reliance on electricity for life,work and production,such as mobile phones,computers,Bluetooth headsets and other consumer electronics products,such as kitchen appliances,TVs and other household appliances,such as modern infrastructure of enterprises,urban construction,etc.Especially as human beings are about to enter the 5G era,the demand for electric energy will increase tremendously.And lithium-ion batteries have slowly developed into the main storage equipment for current electrical equipment.All countries are now seeking the development of green technology,such as green energy and environmentally friendly materials.Titanium dioxide（TiO₂）is an environmental friendly and resource-saving material,and people have never stopped exploring it.It has always been a good photocatalytic material.However,as people’s research on titanium dioxide has become more and more in-depth,it has been found that titanium dioxide has a variety of crystal structures,such as anatase TiO₂,TiO₂（B）,rutile TiO₂,brookite TiO₂,etc.,Among its many crystal forms,researchers found that there are electrode materials suitable for preparing lithium-ion batteries for energy storage devices,so researchers also began to study the electrical properties of titanium dioxide.Titanium dioxide anatase type has bidirectional pore channels and has a higher theoretical specific capacity than other crystal types.Therefore,among the many crystal types of TiO₂,the anatase type is more suitable as a negative electrode material for lithium batteries.Therefore,in the field of titanium dioxide as a negative electrode material for lithium-ion batteries,more researchers have been paying attention to the anatase type,while ignoring other crystal types.Until recent years,some people began to slowly turn their attention to another crystal form of TiO₂（B）.TiO₂（B）belongs to the monoclinic system and has lithium ion migration channels in all directions of the coordinate axis.It has a higher theoretical specific capacity than anatase.Combining it with anatase effectively and used in the negative electrode of a lithium ion battery not only can effectively increase the discharge specific capacity,but also contribute to the stability of the material.In this paper,from the perspective of boosting the specific capacity,enhancing the safety of battery,and improving the stability of the negative electrode of lithium-ion batteries,we have designed and synthesized a variety of nano-level TiO₂ morphologies by hydrothermal methods.The following is the research content of this paper:（1）Prepare single-phase and dual-phase TiO₂ nanosheets with alkaline medium of sodium hydroxide and potassium hydroxide solution in the process of hydrothermal reaction by hydrothermal method.The size of the nanosheets is about 20 nm,with a uniform dispersion,and no agglomeration was observed.The test results show that titanium dioxide microstructure prepared with sodium hydroxide alkaline medium has nano-scale flake morphology,and the mesoporous structure can be clearly seen.These mesoporous structures can speed up the diffusion of electrolyte,accelerate the transfer of lithium ions and electrons effectively,and have a certain contribution to the electrochemical performance of the material.TiO₂ prepared with potassium hydroxide solution as alkaline medium has two crystal types:anatase and TiO₂（B）.It is a dual-phase TiO₂ nanosheet,which is more stable in terms of electrochemical performance than a single-phase TiO₂nanosheet.（2）On the basis of（1）,replace the alkaline medium in the hydrothermal reaction process and use lithium hydroxide solution obtained a morphology completely different from the one prepared in（1）;the nanostructure of hollow spheres appears in the transmission electron microscope.It is also different from the 100nm hollow spheres of previous researchers studied,and its size is about 10-15 nm hollow nanocrystals.Through XRD detection,it can be concluded that not only the anatase but also the corresponding characteristic peak of TiO₂（B）appears,i.e.a dual-phase hollow nanocrystalline TiO₂.This crystal structure and morphology have better electrochemical properties than nanosheets.（3）On the basis of（2）,the influence of different hydrothermal time on the morphology and properties of hollow nanocrystals is studied.