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Fast Diffusion of O2on Nitrogen-Doped Graphene to Enhance Oxygen Reduction and Its Application for High-Rate Zn–Air Batteries
- Source :
- ACS Applied Materials & Interfaces; March 2017, Vol. 9 Issue: 8 p7125-7130, 6p
- Publication Year :
- 2017
-
Abstract
- N-doped graphene (NDG) was investigated for oxygen reduction reaction (ORR) and used as air-electrode catalyst for Zn–air batteries. Electrochemical results revealed a slightly lower kinetic activity but a much larger rate capability for the NDG than commercial 20% Pt/C catalyst. The maximum power density for a Zn-air cell with NDG air cathode reached up to 218 mW cm–2, which is nearly 1.5 times that of its counterpart with the Pt/C (155 mW cm–2). The equivalent diffusion coefficient (DE) of oxygen from electrolyte solution to the reactive sites of NDG was evaluated as about 1.5 times the liquid-phase diffusion coefficient (DL) of oxygen within bulk electrolyte solution. Combined with experiments and ab initio calculations, this seems counterintuitive reverse ORR of NDG versus Pt/C can be rationalized by a spontaneous adsorption and fast solid-state diffusion of O2on ultralarge graphene surface of NDG to enhance effective ORR on N-doped-catalytic-centers and to achieve high-rate performance for Zn–air batteries.
Details
- Language :
- English
- ISSN :
- 19448244
- Volume :
- 9
- Issue :
- 8
- Database :
- Supplemental Index
- Journal :
- ACS Applied Materials & Interfaces
- Publication Type :
- Periodical
- Accession number :
- ejs41273317
- Full Text :
- https://doi.org/10.1021/acsami.6b15235