Study on capacitive performance of bamboo-derived thick carbon electrodes using one-step activation method
With their high-power density,supercapacitors have attracted widespread attention as energy storage devices.This study was aimed at exploring the application of KOH one-step activation method bamboo-based thick carbon elec-trodes in supercapacitors and investigate the impact of activation temperature on performance.In this study,bamboo was employed as the primary material.The advantages of bamboo-based thick carbon electrodes are numerous.Bamboo's innate porous structure,preserved or enhanced through carbonization and activation,boosts electrode surface area,elevating capacitor capacitance.Widely available,bamboo is cost-effective compared to pricier carbon sources,reducing supercapacitor production costs.By utilizing a one-step KOH activation method and capitalizing on the inherent structure of bamboo,the activation temperature was adjusted to refine the pore structure,thereby enhan-cing the ion transport performance of the electrolyte.The preparation process of thick carbon electrodes typically in-volved the carbonization and activation of biomass materials to form electrode materials with rich porous structures.A notable characteristic of biomass-derived carbon materials is their ability to be directly fabricated into thick electrode sheets.The thick carbon electrode refers to a carbon electrode material that is thicker compared to traditional commer-cial electrode sheets.In contrast to the thinner commercial electrode sheets,the millimeter-scale thick carbon electrode can accommodate more active material per unit area,thereby achieving a higher area-specific capacitance.Consequent-ly,a bamboo-derived thick carbon electrode was successfully synthesized in this study.The research results indicated that,with the increase in activation temperature,the electrode's specific capacitance gradually rose,accompanied by an improvement in conductivity.This was attributed to the higher activation temperature's ability to eliminate impurities and promote the formation of porous structures,consequently enhancing the electrode's specific surface area and electronic conductivity.Specifically,at the carbonization temperature of 1 000 ℃,symmetric supercapacitor de-vices exhibited an energy density of 4.86 mWh/cm3 and a power density of 2.57 mW/cm3 at a current density of 1 mA/cm2.Even at an increased current density of 20 mA/cm2,the devices maintained an energy density of 3.13 mWh/cm3.Furthermore,under a current density of 20 mA/cm2,after undergoing 50 000 charge-discharge cycles,the specific capacitance of the HBC1000//HBC1000 symmetric supercapacitor can be sustained at 77％of the initial spe-cific capacitance.This study was aimed at providing scientific basis and technical support for the application of bio-mass-based self-supporting materials in the field of supercapacitors,to meet the growing energy demands and environ-mental requirements by accelerating the advancement of supercapacitor technology.This research offers important ref-erences and insights in this regard.
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