The Preparation Of Puerarin-derived Activation Carbon,Bi And LiBiO₃ Materials And Studies For Their Electrochemical Performance

Carbon materials are regarded as the first candidate electrode materials for supercapacitor because of their low cost,large specific surface area,tunable pore distribution,excellent thermal conductivity,high heat resistance,good electrical conductivity and environmental compatibility.Additionally,due to the increasing demand of people for high energy density of energy storage device,developing a new energy storage material become a hot spot.In this paper,Pueraria was used as a precursor to prepare carbon electrode material for the first time.And we prepare Bi and LiBiO₃ materials,then assemble into asymmetric supercapacitor and alkaline rechargeable battery,with nitrogen doped activated carbon and commercial nickel hydroxide respectively,and studied their electrochemical performance.The main contents of this paper are as follows:1.Nitrogen doped activated carbon was prepared by using puerarin as raw material,K₂CO₃ as activator,melamine as nitrogen source,then by hydrothermal,carbonization,activation and nitrogen doping treatment process.Moreover,we explored the influence of activation temperature,activator agent and nitrogen doping for the physical and electrochemical properties of activated carbon material.Experiments showed that the specific capacitance and specific area of activated carbon are far less than which treated by nitrogen processing.Additionally,with the increase of activation temperature and agent content,the capacitance decrease.It got the best performance when activation temperature was 700 ?,the mass ration of K₂CO₃ and hydrothermal carbon coke was 1:1.At the current density of 0.5 and 10 A g^-1,the specific capacitance of that material were 250 and 231 F g^-1,respectively.2.Bismuth material was prepared by liquid phase reduction method with Bi?NO₃?₃ as the resource of bismuth and NaBH₄ as reduction agent.For asymmetric supercapacitor which using activated carbon as positive and bismuth as negative,at a current density of 0.5 A g^-1,the specific capacity is 215 mAh g^-1,and still retain 74.9%capacity after 1000 cycles at a current density of 5 A g^-1.When matched with Ni?OH?2,The fabricated Bi//Ni alkaline rechargeable battery exhibit a super high specific capacity of 228 mAh g^-1at current density of 0.5 A g^-1,and maintain 73.5% cycling durability after 1000 cycling at a current density of 5 A g^-1.3.LiBiO₃ has been prepared by using NaBi O3 and Li OH through hydrothermal method.For fabricated Li BiO3//AC asymmetric supercapacior,at a current density of0.5 A g^-1,the specific capacity is 165 mAh g^-1.In addition,it still retain 70% capacity after 1000 cycles at a current density of 5 A g^-1.The fabricated LiBiO₃//Ni alkaline rechargeable battery exhibit a specific capacity of 166 mAh g^-1 at a current of 0.5 A g^-1 which centered on the range of 0.75⁰.9 V and possess more then 82% cycling durability after 1000 cycling at a current density of 5 A g^-1.