Neutral aqueous alkali sulfate has shown great interests for developing environmentally friendly high voltage and high energy supercapacitors. This work focuses on systematically investigating the properties of symmet...Neutral aqueous alkali sulfate has shown great interests for developing environmentally friendly high voltage and high energy supercapacitors. This work focuses on systematically investigating the properties of symmetric carbon/carbon supercapacitors in neutral aqueous alkali sulfates. At room temperature, the largest power and energy density were obtained with K2SO4 electrolyte due to the smallest cation dimensions and highest electrical conductivity. At low temperature, aqueous Li2SO4 electrolyte presents the best performance due to the largest solubility, allowing a long-term stability at temperatures ranging between 20℃ and –10℃ at a maximum voltage of 1.8 V. The excellent stability has been confirmed that capacitance retention achieves as high as 92% after 10,000 cycles. The capacitance variations with temperatures could essentially result from kinetic diffusion barrier, ion dimension changes and fewer pseudo-capacitance contributions under different temperatures. This work highlights the selected virtues of different alkali sulfate electrolytes for enhanced supercapacitors.展开更多
基金supported as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy,Office of Science,Office of Basic Energy Sciences
文摘Neutral aqueous alkali sulfate has shown great interests for developing environmentally friendly high voltage and high energy supercapacitors. This work focuses on systematically investigating the properties of symmetric carbon/carbon supercapacitors in neutral aqueous alkali sulfates. At room temperature, the largest power and energy density were obtained with K2SO4 electrolyte due to the smallest cation dimensions and highest electrical conductivity. At low temperature, aqueous Li2SO4 electrolyte presents the best performance due to the largest solubility, allowing a long-term stability at temperatures ranging between 20℃ and –10℃ at a maximum voltage of 1.8 V. The excellent stability has been confirmed that capacitance retention achieves as high as 92% after 10,000 cycles. The capacitance variations with temperatures could essentially result from kinetic diffusion barrier, ion dimension changes and fewer pseudo-capacitance contributions under different temperatures. This work highlights the selected virtues of different alkali sulfate electrolytes for enhanced supercapacitors.
