Study On Preparation And Performance Of SnO₂-based Lithium Ion Battery Anode Materials

With the rapid development of portable electronic products,lithium-ion batteries are widely used in electronic devices due to their fast charge and discharge speeds and high specific capacity.Tin dioxide is a good candidate for negative electrodes due to its high specific capacity,good electron mobility,and low potential for lithium ion insertion.In this paper,SnO₂composite anode material with special morphology based on carbon cloth was synthesized by self-assembly method and template method.This material which directly generates the active material on the carbon cloth can be used as the anode.Compared with the traditional coating method,this method can make the active material and the substrate bind more firmly.The obtained negative electrode material can be applied not only to the traditional battery components,but also to the flexible lithium ion battery.In this paper,a one-dimensional binderless core-shell structure CC/SnO₂ nanotube array was synthesized on a carbon cloth by a simple hydrothermal method.Using Zn O narorods as soft template,the hollow SnO₂nanotube array was obtained.The synthesized nanotube array has a mesoporous structure?with a radius of about 1-12 nm?and a high specific surface area of 168.4 m²/g.It can shorten the transport path of lithium ions and provide space for the volume expansion caused by lithium ion de-intercalation.The cycle performance of the battery was tested at a current density of 200 m A/g.After 200 cycles,the specific capacity was still maintained at 724.9 m Ah/g.At a high current density of 1.8 A/g,their stable specific capacity was still maintained at 380 m Ah/g,which is much better than the reversible capacity of commercial SnO₂ nanoparticles as the negative electrode of lithium ion batteries.Subsequently,in order to synthesize the anode material with better performance,in this paper,TiO₂ nanotubes with stable structure were selected as scaffolds,and a three-dimensional core-shell structure CC/TiO₂ nanotubes@SnO₂ nanosheet array was synthesized by self-assembly method.The electrochemical performance of CC/SnO₂nanosheet electrode and CC/TiO₂ nanotube@SnO₂ nanosheet electrode were also compared.In the first twenty cycles,the specific capacity of the CC/SnO₂ nanosheet electrode is higher than that of the CC/TiO₂ nanotube@SnO₂ nanosheet at current density of 200 m A/g.Although the mass specific capacity of TiO₂ is low,the specific capacity of CC/SnO₂nanosheets decreases rapidly due to structural pulverization without the support of TiO₂nanotubes.The specific capacity of the three-dimensional core-shell CC/TiO₂nanotubes@SnO₂ nanosheets remained at 919 m Ah/g after 200 cycles,proving the necessity of using TiO₂ nanotubes for support.In addition,a flexible battery was assembled with the electrode made in this paper,and the constant current charge and discharge test was performed on the composed flexible battery.The folded battery has no effect on the battery performance,which proves that the three-dimensional core-shell CC/TiO₂ nanotubes@SnO₂nanosheets can be used as flexible anodes for self-supporting anodes.