Improvement of capacitor performance by pitch-based binder for a new alternative to polymer binders

Supercapacitors have gathered attention as one of the necessary energy storage devices. However, the use of polymer binder materials in the preparation of activated carbon-based electrodes hinders ion storage due to blocking the pore structure of activated carbons, and consequently causes reducing the electrochemical performance of EDLCs. We herein demonstrate the employment of pitch as an effective binder material for supercapacitors. The electrode using pitch binder shows a slight to decreased in specific surface area, managing to completely improve the electrochemical performance compared that PVDF binder. Such a fast and strong electrochemical performance ability of pitch-based electrodes are further investigated and verified by experimental and mechanism investigations. Benefitting from the synergistic effect exerts by a pitch in terms of EDLC, using pitch-based electrodes manifests excellent cycling and rate performances. Notably, the obtained pitch-based electrode with a high SSA of 1823 m2/g (PVDF electrode: 1,154 m2/g) delivers outstanding conductivity with 15.431 S/cm compared that a PVDF-based electrode has 6.118 S/cm. More importantly, a pitch-based binder electrode showed a remarkable capacitance of 410.6 mF/cm2 at 1 mA/cm2, as well as a favorable capacitance of 404.0 mF/cm2 after 10,000 cycles with a low-capacity decay of 1.6%. This report paves a practical route toward newly benign binder material design for high-performance EDLCs.