Camellia Pollen‐Derived Carbon with Controllable N Content for High‐Performance Supercapacitors by Ammonium Chloride Activation and Dual N‐Doping

Abstract

Biomass‐derived carbon materials are an amazing electrode material for supercapacitor, owing to their abundant, porous structure and composition. Herein, a controllable N content carbon material with hierarchical porous structure was fabricated via an integrated carbonization, activation and nitrogen‐doping process. N‐rich camellia pollen is used as carbon precursor, while NH4Cl is employed as both activation agent and dopant. The optimal N‐doped carbon with higher N content (3.82 at%), suitable pore size distribution and larger specific surface area (810 m2 g−1), provides abundant ion transport channels and exposes more accessible active sites. Thus, a high specific capacitance of 280 F g−1 (1 A g−1) in 6 M KOH (three‐electrode system) can be obtained with making full use of N−HPC‐1. Moreover, the assembled symmetrical supercapacitor delivers high energy densities both in 6 M KOH (13.3 Wh kg−1) and 1 M Na2SO4 (20 Wh kg−1) that can be used for LED lighting. More than that, it is also demonstrates excellent cycle stability in 6 M KOH (85.4% after 20000 cycles at 20 A g−1). In view of the above‐mentioned merits, this N‐doped hierarchical porous carbon is anticipated to be a promising material for application in supercapacitors and other fields.

Eco-Friendly Preparation of Biomass-Derived Porous Carbon and Its Electrochemical Properties

“…Similar to BCs, the structure of all ACs is also amorphous, in agreement with that reported in previous studies. 42 − 44 However, ACs possess stronger diffraction peaks than BCs. Furthermore, the fraction peaks of ACs shift to a greater 2θ angle direction, indicative of enhanced graphitization degree due to activation at a high temperature.…”

Preparation of N,P Co-doped Porous Carbon Derived from Daylily for Supercapacitor Applications

“…The R CT values of DAC-600, DAC-700, and DAC-800 are 0.59, 0.10, and 0.23 Ω, respectively. The R CT of DAC-700 is obviously lower than that of DAC-600 and DAC-800, which is more beneficial to the energy storage of N, P-containing groups on the surface of DAC-700 electrode through chemical reaction . In the low frequency region of the Nyquist plots, the curves of DAC-700 and DAC-800 were evidently steeper than that of DAC-600.…”

“…The R CT of DAC-700 is obviously lower than that of DAC-600 and DAC-800, which is more beneficial to the energy storage of N, P-containing groups on the surface of DAC-700 electrode through chemical reaction. 33 In the low frequency region of the Nyquist plots, the curves of DAC-700 and DAC-800 were evidently steeper than that of DAC-600. This phenomenon indicated that the hierarchical pore structure of DAC-700 and DAC-800 is conducive to the migration of ions in the electrode, which lead to a relatively lower Warburg diffusion resistance ( Z w ).…”

A sulfur self‐doped multifunctional biochar catalyst for overall water splitting and a supercapacitor from Camellia japonica flowers

“…Camellia japonica (camellia) is an ornamental flower that is widely distributed in East Asia. Considering that the camellia is rich in anionic heteroatoms, it can be a valuable biomass feedstock for the synthesis of biochar 35,36 …”

“…Considering that the camellia is rich in anionic heteroatoms, it can be a valuable biomass feedstock for the synthesis of biochar. 35,36 In this study, sulfur self-doped activated camellia (SA-Came) nanospheres were prepared using a solvothermal-pyrolysis method with camellia flowers as raw materials. During the process, sulfur atoms were naturally doped into the carbon nanospheres without additional doping precursors.…”