Abstract
Nanocomposites consisting of ultrafine, cobalt carbonate nanoneedles and 3D porous graphene aerogel (CoCO3/GA) are in situ synthesized based on a one-step hydrothermal route followed by freeze-drying. A further heat treatment produces cobalt oxide nanoparticles embedded in the conductive GA matrix (Co3O4/GA). Both the composite anodes deliver excellent specific capacities depending on current density employed: the CoCO3/GA anode outperforms the Co3O4/GA anode at low current densities, and vice versa at current densities higher than 500 mA g-1. Their electrochemical performances are considered among the best of similar composite anodes consisting of CoCO3 or Co3O4 active particles embedded in a graphene substrate. The stable multistep electrochemical reactions of the carbonate compound with a unique nanoneedle structure contribute to the excellent cyclic stability of the CoCO3/GA electrode, whereas the highly conductive networks along with low charge transfer resistance are responsible for the high rate performance of the Co3O4/GA electrode.
Original language | British English |
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Pages (from-to) | 18971-18980 |
Number of pages | 10 |
Journal | ACS Applied Materials and Interfaces |
Volume | 6 |
Issue number | 21 |
DOIs | |
State | Published - 12 Nov 2014 |
Keywords
- anode
- cobalt carbonate
- cobalt oxide
- graphene aerogel
- hydrothermal process
- Li-ion battery