Dodecylamine (DDA) was functionalized on Fe2O3 nanocrystals (NCs) by a solvothermal process to allow electrostatic interaction on Brønsted acid sites induced on the surface of NCs, followed by carbonization to convert DDA into a thin layer of carbon on single Fe3O4 NCs. The obtained carbon composite (IOC-Fe3O4) is composed of Fe3O4 NCs a few nanometers in size, each uniformly coated with a thin carbon layer. The carbon coating reduces the resistance at the NC-to-NC interface within the composite and retains a short lithium diffusion length by inhibiting crystal growth, as well as accommodating the volume change of Fe3O4 during charge-discharge. The composite electrode exhibited a high reversible capacity of 1027 mA h g-1 in a lithium ion battery, as well as 100% capacity retention after 300 cycles and rate performance of 563 mA h g-1 at 3 A g-1, which was achieved with only 4.2 wt% carbon in the composite. The relationship between the enhanced diffusion kinetics of IOC-Fe3O4 and excellent electrochemical performances is demonstrated through a voltammetric charge technique.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2015R1A2A2A03006633).
© The Royal Society of Chemistry 2016.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)