Microwave Irradiation Synthesis Of And Electrochemical Energy Storage Materials And It's Application

The porous carbon?microporous carbon,mesporous and hierarchic porous carbon et al?,an ideal energy storage material due to its developed pore and outstanding conductivity,porous carbon has been used as electrochemical energy storage systems including lithium-ion batteries and supercapacitors.In this paper,hierarchic porous carbon and mesporous carbon materials with different morphologies were successfully prepared by using microwave irradiation method,which is a energy-efficient and ultra-facile method for fabricating porous carbon without the active agent under ambient atmosphere.The electrochemical performance of the materials fabricated by the above method were tested,meanwhile,the structure and morphology of the fabricated materials were also characterized.The egg-liked phosphorus doped hierarchic porous carbon materials with superior supercapacitor performance were successfully prepared under air atmosphere by using phytic acid as precursor through microwave irradiation combining with self-activation strategy.The samples fabricated by the reported method have a unique opened micropore and phosphorus-doped egg-liked hierarchic porous structure.The specific surface area and pore volume of the prepared samples were achieved 1642 m² g^-1 and 2.04 cm³ g^-1 respectively.The prepared PHPC-W series samples show large charge storage capacity and excellent rate performance that the specific surface can reache up to 209 F g^-1 when the current density is 0.5 A g^-1,and over 96.2%of initial capacitance remains as current density increasing from 0.5 to 20 A g^-1.What's more,the capacitance rate can reach over 97.9%for PHPC-W series samples after 5000 times charge/discharge cycles.All of these features indicate that the prepared samples have excellent electrochemical performance.Phosphorus-doped mesoporous carbon materials with supercapacitor properties were successfully prepared in air atmosphere by using inositol as the precursor,water as the porogen and phosphoric acid as the microwave absorber and source of phosphorous through energy-efficient microwave irradiation.The specific surface area of the prepared materials can achieve210 F g^-11 when the current density is 0.5 A g^-1and the capacitance retention is 95.7%when the current density increasing to 20 A g^-1.Meanwhile,95.01%of initial capacitance remains after5000 times charge/discharge cycles.The features above showed that the prepared samples have great charge storage capacity and excellent rate performance.In addition to these characteristics,the fabricated samples also have extremely high power density and energy density,when using EMIMBF₄ ionic liquids as electrolyte,the power density and energy density of the samples can achieve 306.98 W Kg^-11 and 16.61 Wh Kg^-11 respectively,while the energy density can reach7.28 Wh Kg^-1 when using 6 mol L^-1 KOH as the electrolyte.The co-doped bird nested nitrogen and phosphorous mesoporous carbon materials with excellent capacitance performance were prepared by combining microwave heating with ultra high temperature solvothermal method without the protection of inert atmosphere.To prepared the samples above,a highly polar protic acid polyphosphoric acid with ultrahigh boiling point and good microwave response was used as a solvent and pyrrole was used as a precursor.The specific surface area and pore volume of the fabricated materials that has a unique bird nest mesoporous structure achieved 922 m² g^-1 and 0.92 cm³ g^-1,respectively,while the nitrogen content reached up to 3.45 at.%.Meanwhile,the fabricated samples have excellent rate performance and cycle performance,the specific capacitance reached 171 F g^-1 at 0.2 A g^-1current density and the capacitor retention can be maintained at 95.9%when the current density increased to 20 A g^-1 by using KOH as electrolyte.The samples was also tested for 5000cycles of charge and discharge to show its good cycle performance,the results showed that samples capacitance retention rate can reached 95.2%.When using 3 mol L^-1 Li NO₃ as the electrolyte,the prepared materials has a large voltage window?1.3V?,and the specific capacitance of samples can achieve 101 F g^-1 at 0.2 A g^-1 current density.After 5,000 cycles of charge and discharge tests,the materials also showed good cycle stability.