Wood and PAN-derived hierarchically porous low-tortuosity carbon electrodes for high-areal-performance supercapacitors

Abstract

Carbonized wood not only well retains the original hierarchical pore structure and full openly straight channels of wood, but also has structural stability and conductivity, which make it considered as a low tortuosity 3D self-support porous carbon networks electrode material with conductive-free and binder-free for supercapacitor. However, carbonized wood as a self-support electrode of supercapacitor still has some problems, such as relatively low specific surface area, not effective use of pore structure and excessive absorption of electrolyte, which seriously affects the performance of its supercapacitor. Herein, a 3D porous network of pure carbon PCN/CW electrode with high specific surface area was prepared by effective filling and re‑carbonization of the polymer PAN in carbonized wood. The PCN/CW electrode not only realized the effective filling and regulation of the carbonized wood channel solved the problem of excessive adsorption of electrolyte by the electrode, but also improved the specific surface area without introducing other substances. The obtained PCN/CW electrode exhibits high areal capacitance up to 5547 mF cm−2 at 5 mA cm−2, its symmetrical supercapacitor (PCN/CW//PCN/CW-60) delivers a maximum areal energy density of 0.26 mWh cm−2 at power density of 1.19 mW cm−2 with an outstanding capacitance retention of 97.4 % after 10,000 cycles.