Intercalation of Sodium
Ions into Hollow Iron Oxide
Nanoparticles
Bonil Koo
Soma Chattopadhyay
Tomohiro Shibata
Vitali B. Prakapenka
Christopher S. Johnson
Tijana Rajh
Elena V. Shevchenko
10.1021/cm303611z.s001
https://acs.figshare.com/articles/journal_contribution/Intercalation_of_Sodium_Ions_into_Hollow_Iron_Oxide_Nanoparticles/2450035
Cation vacancies in hollow γ-Fe<sub>2</sub>O<sub>3</sub> nanoparticles
are utilized for efficient sodium ion transport. As a result, fast
rechargeable cathodes can be assembled from Earth-abundant elements
such as iron oxide and sodium. We monitored in situ structural and
electronic transformations of hollow iron oxide nanoparticles by synchrotron
X-ray adsorption and diffraction techniques. Our results revealed
that the cation vacancies in hollow γ-Fe<sub>2</sub>O<sub>3</sub> nanoparticles can serve as hosts for sodium ions in high voltage
range (4.0–1.1 V), allowing utilization of γ-Fe<sub>2</sub>O<sub>3</sub> nanoparticles as a cathode material with high capacity
(up to 189 mAh/g), excellent Coulombic efficiency (99.0%), good capacity
retention, and superior rate performance (up to 99 mAh/g at 3000 mA/g
(50 C)). The appearance of the capacity at high voltage in iron oxide
that is a typical anode and the fact that this capacity is comparable
with the capacities observed in typical cathodes emphasize the importance
of the proper understanding of the structure–properties correlation.
In addition to that, encapsulation of hollow γ-Fe<sub>2</sub>O<sub>3</sub> nanoparticles between two layers of carbon nanotubes
allows fabrication of lightweight, binder-free, flexible, and stable
electrodes. We also discuss the effect of electrolyte salts such as
NaClO<sub>4</sub> and NaPF<sub>6</sub> on the Coulombic efficiency
at different cycling rates.
2016-02-20 00:53:40
vacancy
voltage
Coulombic
2O
sodium ion transport
cathode
capacity
Hollow Iron Oxide NanoparticlesCation vacancies
efficiency
iron oxide nanoparticles
Fe
mAh
iron oxide