A supercapacitor constructed with a partially graphitized porous carbon and its performance over a wide working temperature range

A supercapacitor that possesses excellent performance in a wide temperature range is constructed with a partially graphitized porous carbon (PGPC) as the electrode material and tetraethylammonium tetrafluoroborate/propylene carbonate (Et4NBF4/PC) as the electrolyte. The PGPC-based electrode shows a very consistent performance in a wide temperature range of -20 to 50 degrees C. At working temperatures as high as 50 degrees C and as low as -20 degrees C, it delivers specific capacitances of similar to 148 and similar to 135 F g(-1), respectively, and the supercapacitors exhibit high energy densities of similar to 46 and similar to 43 W h kg(-1). In particular, the low-temperature capacitive performance and rate capability of PGPC are much better than those of the normally used activated carbon and among the best ones ever-reported for carbon-based supercapacitors. More significantly, the PGPC-based supercapacitor shows excellent cycling performance at all tested working temperatures, with a capacitance retention of similar to 98% after 1000 cycles at 5 A g(-1) even when the working temperature decreases to -20 degrees C.