Three-dimensional activated graphite paper for high-performance supercapacitors

Abstract

Developing electrodes with both high specific capacity and high rate performance is critical for high-performance supercapacitors. Three-dimensional current collector is essential for achieving high specific capacity and high rate capability because it can not only significantly improve active materials' mass loading and uniformity, but also largely benefit the charge transfer. Herein, a simple electrochemical-assisted method is developed to activate graphite paper under room temperature. The activated graphite paper (AGP) features both low structural defects and an open structure with partially exfoliated graphite sheets anchoring on the base of graphite paper. After hybridizing NiCo layered double hydroxide (NiCo-LDH), the obtained sample (AGP@NiCo-LDH) presents a high specific capacity of 875 C g−1 at 1A g−1 and excellent rate capability (87.3% capacitance retention at 20 A g−1). Furthermore, the assembled asymmetric supercapacitor based on AGP@NiCo-LDH shows a high energy density of 27.56 Wh kg−1 at a power density of 16.0 kW kg−1 and excellent cycling stability (94.4% of the initial capacitance retention at 10 A g−1 over 5000 cycles).