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High‐Potential Metalless Nanocarbon Foam Supercapacitors Operating in Aqueous Electrolyte
Author(s) -
Liu Chueh,
Li Changling,
Ahmed Kazi,
Mutlu Zafer,
Lee Ilkeun,
Zaera Francisco,
Ozkan Cengiz S.,
Ozkan Mihrimah
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201702444
Subject(s) - supercapacitor , electrolyte , materials science , aqueous solution , chemical engineering , nanotechnology , electrochemistry , electrode , chemistry , organic chemistry , engineering
Light‐weight graphite foam decorated with carbon nanotubes (dia. 20–50 nm) is utilized as an effective electrode without binders, conductive additives, or metallic current collectors for supercapacitors in aqueous electrolyte. Facile nitric acid treatment renders wide operating potentials, high specific capacitances and energy densities, and long lifespan over 10 000 cycles manifested as 164.5 and 111.8 F g −1 , 22.85 and 12.58 Wh kg −1 , 74.6% and 95.6% capacitance retention for 2 and 1.8 V, respectively. Overcharge protection is demonstrated by repetitive cycling between 2 and 2.5 V for 2000 cycles without catastrophic structural demolition or severe capacity fading. Graphite foam without metallic strut possessing low density (≈0.4–0.45 g cm −3 ) further reduces the total weight of the electrode. The thorough investigation of the specific capacitances and coulombic efficiencies versus potential windows and current densities provides insights into the selection of operation conditions for future practical devices.