Comparation of porous bamboo activated carbon using KOH co-thermal activation and hydrothermal activation methods
China is indeed rich in bamboo resources,which has advantages of fast-growing,low-cost,and biodegrada-ble.Activated carbon prepared from bamboo wastes can be used as an electrode material for supercapacitors,which helps to promote the development of the bamboo industry and contribute to the national goal of the"Dual-Carbon"strategy.In this study,bamboo powder was activated by KOH co-heating and hydrothermal treatment respectively,and the electrochemical properties,specific surface area,and surface micro-morphology of the prepared bamboo acti-vated carbons were examined.The mechanism of the differences performance in the activated carbon prepared by these two methods was also characterized using the Brunauer,Emmett and Teller(BET),scanning electron microscope(SEM),X-ray diffraction(XRD)and Ramon analysis.The results showed that the optimum conditions of KOH co-heating activation method were the charring temperature of 350℃,activation temperature of 900℃,heating rate of 2℃/min,and the KOH to charcoal mass ratio of 4∶1.The specific surface area of the prepared activated carbon was 3 299 m2/g,and the specific capacitance was 287.8 F/g at a current density of 0.5 A/g,and the power density and energy density were 6.94 Wh/kg and 1 250 W/kg,respectively.The capacitance retention was 95%-105%after 5 000 cycles of charging and discharging tests.The optimum conditions of hydrothermal activation method were KOH solution mass fraction of 20%,reaction temperature of 150℃,and reaction time of 12 h.The specific surface area of the prepared activated carbon was 192.91 m2/g,and the specific capacitance was 170.4 F/g at a current density of 0.5 A/g.The power density and energy density were 1.88 Wh/kg and 250 W/kg,respectively,and the capacitance reten-tion was only 88.89%.The pore size structure of both activated carbons was dominated by micropores with a mixed distribution of mesopores,containing a small number of macropores,contributing to facilitate the transport of electro-lyte ions in the samples.Both activated carbons prepared by these two methods contained bi-or multi-layer graphene structure,but the capacitive performance of the KOH co-heating activated carbon was better.However,the carbon prepared by the hydrothermal activation method using the mild preparation conditions had a higher degree of graphiti-zation and lower resistance,and the internal structure was more ordered,thus it can be used as a conductive agent.This study not only provides theoretical ideas for the investigation of activated carbon for supercapacitors,but also ef-fectively improves the added value and expands the application fields of bamboo.
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维普
