Improving the low-temperature capacitance of CoNiAl three-component layered double hydroxide in a redox electrolyte

摘要

CoNiAl three-component layered double hydroxide with a lamellar structure similar to hydrotalcite-like compounds is synthesized via homogeneous precipitation and the effect of temperature on its capacitive performances in 6 M KOH is investigated. Electrochemical tests show its specific capacitance reduces sharply with the decrease of temperature from 18 to -20℃. At -20℃ an increase of specific capacitance by 178% is achieved by adding redox pair Fe(CN)_6~(3-)/Fe(CN)_6~(4-) as the electron shuttle in the electrolyte due to their cooperation with the electrode reaction during the charge/discharge processes.