Design Of Carbon Encapsulated Hollow Structures For High-Performance Lithium Ion Batteries

Rechargeable lithium ion batteries are widely applied in electronic devices and vehicles due to their environmental friendliness and safety.With the increase of requirements,traditional lithium ion batteries using graphite as anode material are gradually insufficient to fulfill the demands for high performance batteries.Antimony trisulfide and tin dioxide have drawn especial attentions for high theoretical specific capacity,low operating voltage,low cost and non-pollution.However,some immanent deficiency such as volume expansion of up to 300 % during charging and discharging and low electroconductivity,which make its capacity diminished so that limits commercial application.Therefore,it is necessary to mitigate the damage to the electrode structure caused by the volume change of the electrode material in the process of charging and discharging,reduce the impedance of the electrode material and improve the cycling stability.In this paper,the electrochemical properties of antimony trisulfide and tin dioxide as anode materials were studied by combining with hollow carbon materials.Ultrafine antimony trisulfide nanoparticles embedded in hollow mesoporous carbon nanospheres and tin dioxide nanostructures coated in hollow carbon nanoboxes were successfully prepared by hydrothermal process,water bath,hard templates and low temperature annealing in an inert atmosphere.High specific capacity,excellent cycle stability and prominent rating performance were achieved when applied to anode.Antimony trioxide embedded in the hollow mesoporous carbon nanospheres delivered a desirable specific capacity of 745.3 mAh/g after 160 cycles at a current density of 100 mA/g,and 495.8 mAh/g after 400 cycles at a current density of 500 mA/g.After 100 and 400 cycles under current density of 100 mA/g and 500 mA/g,the reversible specific capacities for tin dioxide nanomaterials coated with hollow carbon nanomaterials can reach 654.1 mAh/g and 387.9 mAh/g,respectively.Remarkable performances have been displayed by this kind of carbon coated hollow nano materials,which can be attributed to connatural high theoretical specific capacity of sulfide antimony and tin dioxide,and hollow structure of carbon composite material conquer the volume expansion,at the same time,the coating carbon materials enhanced the conductivity,so improve the electrochemical performance.The method adopted in this paper is simple,low cost and uniform size,which can be used for reference to develop high performance anode materials with large volume expansion.