S doping coupled with pore-structure modulation to the conductive carbon black: Toward high mass loading electrical double-layer capacitor

The conductive carbon black (CB) was modified by the pore-structure modulation and S doping in the presence of pore-modulation agent and S dopant via the one-step calcination methodology, resulting in the S-doped and pore-structure modified CB (labeled as SPCB). The conductivity and contact angle tests prove that the function of S doping can not only increase the electrical conductivity but also enhance the hydrophilicity. As electrode materials for symmetric electrical double-layer capacitor (EDLC), the influence of different mass loading of the electrode on the capacitive behavior is investigated. The areal mass loading of active materials for each electrode in the symmetric EDLC can reach up to 10 mg cm−2, comparable to the values of commercial devices. Without obvious sacrifice of the gravimetric capacitance is observed with the increase of mass loading, illustrating the small electrolyte ion transport resistance in electrode material and quick charge transfer property as well as the great compatibility for the gravimetric, areal and total capacitances. Additionally, the symmetric EDLC configured with SPCB affords the larger capacitance, better rate capability and higher capacitance retention as compared to the commercial activated carbon.