Facile cyclic ammonium salt with the smallest size for high performance electric double layer capacitors

The smallest cyclic ammonium salt reported to date, N,N-dimethylpyrrolidinium tetrafluoroborate (P₁₁-BF₄), was successively synthesized using a synthesis route without metal ions and halogen ions, then investigated as the electrolyte with Propylene carbonate in EDLCs. The electrochemical characteristics of EDLCs assembled by 1 mol/L P₁₁-BF₄/PC paired with activated carbon electrodes were compared to traditional electrolytes. P₁₁-BF₄ has proven to have superior voltage resistance by using cyclic voltammetry and constant current charge-discharge testing. Moreover, P₁₁-BF₄ exhibits a more brilliant rate performance due to its high conductivity. These results demonstrate that P₁₁-BF₄ is an ideal electrolyte to improve the energy density and power density of supercapacitors.