Preparation And Electrochemical Properties Of Potato Starch-based Carbon Spheres

In recent years,lithium-ion batteries have gained great development in many fields.The electrochemical performance of lithium-ion batteries has become more and more significant and crucial for the extended potential applications.Therefore,anode materials with green-preparation,safety and high-capacity have become a research hotspot.With the depletion of fossil fuels and the growing environmental problems,it is extremely urgent to find new types of clean and renewable resources.As a kind of carbonaceous precursor material,starch is rich in yield,environmental friendly,biodegradable and economical.The potato starch has a natural spherical shape,and spheroidization is not required when preparing carbon spheres,which simplifies the preparation process of carbon spheres and reduces production costs.In this study,using potato starch as raw material,iron powder and carbon black as additive respectively,the highly dispersed starch based carbon microspheres were prepared by stabilizing treatment in air subsequent carbonization at high temperature.The morphology and structure of carbon spheres were characterized and the electrochemical properties as anode materials for Li-ion batteries were studied.In the process of preparing carbon microspheres,iron powder can separate starch particles from each other by physical dispersion,which makes starch particles heat evenly,accelerates the process of starch dehydration,polycondensation and cross-linking,and shortens the stabilization time.When the weight ratio of iron powder to starch was 100%,the carbon spheres with a specific surface area of 274m2/g and a pore volume of 0.15cm3/g were prepared after 6 hours of stabilization.It exhibits excellent rate performance and cycle performance when was used as anode material of Li-ion battery.The specific capacity can attain 298mAh/g after 50 cycles at a current density of 50mA/g.The high-dispersed carbon spheres were also prepared by adding carbon black as additive,which has excellent spherical morphology.On one hand,carbon black can promote the stabilization process of starch,on the other hand,it can increase the conductivity of the carbon microsphere negative electrode and improve its specific capacity.The results show that the specific surface area of carbon sphere prepared by stabilizing for 6h with carbon black of 1%is 351m2/g,the pore volume is 0.19cm3/g.The carbon microspheres possess the specific capacities of 324 and 105mAh/g after 50 and 10 cycles at 50 and 2000mA/g,respectively.