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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Direct observation of ion dynamics in supercapacitor electrodes using in situ diffusion NMR spectroscopy
AU - Forse, Alexander C.
AU - Griffin, John M.
AU - Merlet, Celine
AU - Carretero-Gonzalez, Javier
AU - Raji, Abdul-Rahman O.
AU - Trease, Nicole M.
AU - Grey, Clare P.
N1 - © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
PY - 2017/2/6
Y1 - 2017/2/6
N2 - Ionic transport inside porous carbon electrodes underpins the storage of energy in supercapacitors and the rate at which they can charge and discharge, yet few studies have elucidated the materials properties that influence ion dynamics. Here we use in situ pulsed field gradient NMR spectroscopy to measure ionic diffusion in supercapacitors directly. We find that confinement in the nanoporous electrode structures decreases the effective self-diffusion coefficients of ions by over two orders of magnitude compared with neat electrolyte, and in-pore diffusion is modulated by changes in ion populations at the electrode/electrolyte interface during charging. Electrolyte concentration and carbon pore size distributions also affect in-pore diffusion and the movement of ions in and out of the nanopores. In light of our findings we propose that controlling the charging mechanism may allow the tuning of the energy and power performances of supercapacitors for a range of different applications.
AB - Ionic transport inside porous carbon electrodes underpins the storage of energy in supercapacitors and the rate at which they can charge and discharge, yet few studies have elucidated the materials properties that influence ion dynamics. Here we use in situ pulsed field gradient NMR spectroscopy to measure ionic diffusion in supercapacitors directly. We find that confinement in the nanoporous electrode structures decreases the effective self-diffusion coefficients of ions by over two orders of magnitude compared with neat electrolyte, and in-pore diffusion is modulated by changes in ion populations at the electrode/electrolyte interface during charging. Electrolyte concentration and carbon pore size distributions also affect in-pore diffusion and the movement of ions in and out of the nanopores. In light of our findings we propose that controlling the charging mechanism may allow the tuning of the energy and power performances of supercapacitors for a range of different applications.
KW - QUARTZ-CRYSTAL MICROBALANCE
KW - DOUBLE-LAYER CAPACITORS
KW - NANOPOROUS CARBON ELECTRODES
KW - ELECTRICAL DOUBLE-LAYER
KW - SOLID-STATE NMR
KW - TRANSPORT-PROPERTIES
KW - MAGNETIC-RESONANCE
KW - MICROPOROUS CARBON
KW - CHARGING DYNAMICS
KW - ENERGY-STORAGE
U2 - 10.1038/nenergy.2016.216
DO - 10.1038/nenergy.2016.216
M3 - Journal article
VL - 2
JO - Nature Energy
JF - Nature Energy
SN - 2058-7546
IS - 3
M1 - 16216
ER -