Open AccessHigh-Performance and High-Voltage Supercapacitors Based on N-Doped Mesoporous Activated Carbon Derived from Dragon Fruit Peels
Author(s) -
Dayakar Gandla,
Xudong Wu,
Fuming Zhang,
Chongrui Wu,
Daniel Q. Tan
Publication year - 2021
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.0c06171
Subject(s) - supercapacitor , capacitance , materials science , mesoporous material , electrolyte , chemical engineering , activated carbon , dopant , electrode , doping , nanotechnology , optoelectronics , chemistry , organic chemistry , adsorption , engineering , catalysis
Designing the mesopore-dominated activated carbon electrodes has witnessed a significant breakthrough in enhancing the electrolyte breakdown voltage and energy density of supercapacitors. Herein, we designed N-doped mesoporous-dominated hierarchical activated carbon (N-dfAC) from the dragon fruit peel, an abundant biomass precursor, under the synergetic effect of KOH as the activating agent and melamine as the dopant. The electrode with the optimum N-doping content (3.4 at. %) exhibits the highest specific capacitance of 427 F g -1 at 5 mA cm -2 and cyclic stability of 123% capacitance retention until 50000 charge-discharge cycles at 500 mA cm -2 in aqueous 6 M KOH electrolytes. We designed a 4 V symmetric coin cell supercapacitor cell, which exhibits a remarkable specific energy and specific power of 112 W h kg -1 and 3214 W kg -1 , respectively, in organic electrolytes. The cell also exhibits a significantly higher cycle life (109% capacitance retention) after 5000 GCD cycles at the working voltage of ≥3.5 V than commercial YP-50 AC (∼60% capacitance retention). The larger Debye length of the diffuse ion layer permitted by the mesopores can explain the higher voltage window, and the polar N-doped species in the dfAC enhance capacitance and ion transport. The results endow a new path to design high-capacity and high-working voltage EDLCs from eco-friendly and sustainable biomass materials by properly tuning their pore structures.