Carbon Derived From Supramolecular Assembled Polypyrrole As Supercapacacitor Electrode Material

Storage and utilization of energy is the engine of modern society.Supercapacitor has been regarded as one of the most promising sustainable energy storage technology to alleviate the growing energy demand in face of continuous depletion of fossil fuels and excessive greenhouse gasses,because of its intriguing characteristics of high power density,extraordinary cycle life,and high energy efficiency.Generally,the amount of charge stored by electric double layer(EDL)does not meet the growing performance demands.An alternatively essential way to enhance the specific capacitance is to utilize Faradaic reactions by employing pseudocapacitance materials,such as conducting polymers,doped carbon materials,transition metal oxides(TMOs),metal organic frameworks(MOFs),etc.Among them,carbon materials are outstanding because of their high surface area,abundant low dimensional morphologies,and superb physical/chemical robustness(which prolongs the electrode lifespan to tens of thousands of cycles).Carbonization of precursors is an import approach for preparation of doped carbon materials.Precursors has an great effect on the final products,including their conductivity,morphology,and doped contents.Given consideration to that these characteristics synergistically determine the supercapacitive performance,rationally designed precursor of N-doped carbon is crucial for high performance carbon materials of supercapacitor electrode.Herein,we report a scalable preparation of hierarchically structrued N-doped carbon of micro/meso porous nanofiber morphology by using a supramolecular assmebled polypyrrole as precursor.The Influences of the dose of supramolecular dopant on final products after carbonization and sequential chemical activation were investigated.The interconnected nanofiber backbone allows better electron transport and the optimized hierarchically porous structure of material exhibits a large specific surface area of 2113.2 m2 g-1.The N content of the carbon is as high as 6.49 atom%,which are faborable to improve the supercapacitive performance via additional reversible redox reaction over pure carbon.The hierarchically porous N-doped carbon electrode delivered outstanding specific capacitance of 435.6 F g-1 at 0.5 A g-1,significantly higher than the control sample derived from undoped polypyrrole samples.Moreover,the capacitance retention is as high as 96.1%after 5000 cycles.This precursors structural control route is general and readily applicable to various conducting polymers,and provided a methodology to design carbon materials with advanced structure for developing high-performance supercapacitor electrode material.