CORN COB LIGNIN-BASED POROUS CARBON MODIFIED REDUCED GRAPHENE OXIDE FILM FOR FLEXIBLE SUPERCAPACITOR ELECTRODE

摘要

Flexible supercapacitors (FSCs) have attracted widespread attention of many researchers as a type of portable energy storage devices. However, there are still challenges in preparing renewable and inexpensive electrode materials. Herein, we prepared the porous carbon (PC) by the two-step process involving hydrothermal method and low-temperature heat treatment using corn cob lignin as the carbon source, and different types for PC were obtained by changing the temperature of low temperature heat treatment (100 degrees C-300 degrees C). The flexible electrode film was prepared by combining the obtained corn cob lignin-based PC with reduced graphene oxide (RGO), in addition, we investigated the effect of PC obtained by different low-temperature heat treatment (100 degrees C, 150 degrees C, 200 degrees C, 250 degrees C, and 300 degrees C) on the electrochemical properties of the composite electrode. The optimal low-temperature heat treatment temperature (250 degrees C) was determined and the PC250/RGO film electrodes displayed a high area specific capacitance of 636 mF/cm(2) with a mass of 2.2 mg/cm(2) (specific capacitance of 289 F/g) at 0.2 mA/cm(2) and 82% of the capacitance was retained after 10,000 charge and discharge cycles at 5 mA/cm(2), at the same time on the electrode film flexibility test, the influence of different bending angle on the electrochemical properties can be ignored. The assembled supercapacitor had the advantages of flexible, lightweight, low price, and environment friendly, which can achieve area specific capacitance of 324.5 mF/cm(2) at 0.2 mA/cm(2) and 91.8% capacitance retention after 1000 charging/discharging cycles. These good electrochemical properties illustrate the application prospects of composite electrode materials in wearable and portable electronic devices.