In situ growth of N/O-codoped carbon nanotubes in wood-derived thick carbon scaffold to boost the capacitive performance

Structural and compositional optimization are considered as vital strategies to improve the capacitive properties of carbon-based electrodes. Inspired by the abundant vertically aligned micron-sized low-tortuosity porous channels of natural wood, a facile, low-energy, and efficient approach that anchors N/O-codoped carbon nanotubes on the inner and outer surfaces of carbonized wood matrix through in-situ chemical vapor deposition is proposed. The as-prepared thick carbon monoliths have unique three-dimensional hierarchically porous structures, interconnected conductive networks, and rich N/O-containing species, consequently endowing the electrodes with ultrahigh mass loading and inspiring capacitive properties. Representatively, the [email protected] electrode (∼56 mg cm−2) improves the specific capacitance to 6620.3 mF cm−2 (118.5 F g−1, 82.8 F cm−3) at 2 mA cm−2. And the robust electrode exhibits an outstanding cycle stability even after 20,000 charge/discharge cycles at 30 mA cm−2 (5.4% decay). Furthermore, the maximum specific capacitance and energy density of the assembled symmetric supercapacitor are 4120.0 mF cm−2 (51.5 F cm−3, 42.9 F g−1) and 0.6 mWh cm−2 (6.3 mWh cm−3, 6.0 Wh kg−1), respectively. The above strategies will open up a new path for the value-added utilization of renewable resources and the efficient preparation of low-cost and high-performance energy storage and conversion devices.