Development of high voltage electrolyte is one of the effective ways to improve the performance of supercapacitor. The new ionic liquid N-propyl-N-methylpyrrolidinium difluoro(oxalato)borate (Py13DFOB) was designed and mixed with propylene carbonate (PC) as electrolyte for supercapacitor. The operating voltage of the new electrolyte system has been proven to be up to 3.0 V by a series of electrochemical techniques. Surprisingly, the new salt exhibits nearly symmetric capacitance contribution in the positive and negative electrodes, leading to a high capacitance value of 130 F g−1. The energy and power density of EDLCs using Py13DFOB in the PC electrolyte reach 39.06 Wh kg−1 (100 mA g−1) and 8.03 kW kg−1 (5,000 mA g−1), respectively, at the working voltage of 3.0 V, significantly exceeding the performance of commercial electrolyte tetraethylammonium tetrafluoroborate (TEABF4). The results indicate that Py13DFOB can be a promising electrolyte salt for supercapacitor.
Na2SO4 and spiro-(1,1′)-bipyrrolidinium
tetrafluoroborate (SBPBF4) are very promising electrolytes
with low cost and high conductivity. For matching with two electrolytes
to boost the energy density of the supercapacitor, a suitable electrode
needs to be fabricated. Herein, porous carbon derived from discarded
polyimide films is fabricated via H3PO4-assisted
KOH activation. The hierarchical pore framework of porous carbon,
which consists of micro–mesopores concentrated at 0.7–1
nm and >2 nm along with abundant cracks in the cross section, increases
the effective energy storage sites and facilitates the ion diffusion
rate of electrolytes. The high synergy between electrolytes and the
architecture of electrodes endows the symmetrical capacitors (SCs)
with outstanding performance. The SC in the Na2SO4 electrolyte delivers the operating voltages of 1.8 V and an energy
density of 23.2 Wh kg–1 at a power density of 450
W kg–1. In the SBPBF4 electrolyte, the
SC exhibits a high withstand voltage of 3.2 V and a conspicuous energy
density of 70.2 Wh kg–1 at a power supply of 320
W kg–1. This work constructs a cooperative system
of porous carbon electrodes and electrolytes boosting the energy density
of supercapacitors and a sustainable strategy for resource utilization
of discarded polyimide films.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.