Nowadays, supercapacitor devices employed in the practical application have been growing
rapidly, ranging from consumer electronics and hybrid electric vehicles to industrial electric
utilities. However, there are certain disadvantages in the supercapacitors, including low energy
density and high production cost, which are still considered to be tremendous challenges in
their developments. Herein, a new kind of high-energy-density symmetric supercapacitor,
energy density of 11.0 mWh cm3 and power density of 1543.7 mW cm3
, has been designed
using 2.0 M Li2SO4 aqueous solution as the electrolyte and carbon cloth (CC) with α-Fe2O3
nanoneedles grown on (CC/Fe2O3) as electrode materials. Furthermore, the fabrication of this
kind of supercapacitor is low-cost, easily operational, environmentally friendly, practicable,
and scalable, which indicates this method is feasible to fabricate cost-effective high-energydensity
supercapacitors.