Abstract
The electrode materials conducive to conversion reactions undergo large volume change in cycles which restrict their further development. It has been demonstrated that incorporation of a third element into metal oxides can improve the cycling stability while the mechanism remains unknown. Here, an in situ and ex situ electron microscopy investigation of structural evolutions of Cu-substituted Co3O4 supplemented by first-principles calculations is reported to reveal the mechanism. An interconnected framework of ultrathin metallic copper formed provides a high conductivity backbone and cohesive support to accommodate the volume change and has a cube-on-cube orientation relationship with Li2O. In charge, a portion of Cu metal is oxidized to CuO, which maintains a cube-on-cube orientation relationship with Cu. The Co metal and oxides remain as nanoclusters (less than 5 nm) thus active in subsequent cycles. This adaptive architecture accommodates the formation of Li2O in the discharge cycle and underpins the catalytic activity of Li2O decomposition in the charge cycle.
| Original language | English (US) |
|---|---|
| Article number | 1704851 |
| Journal | Advanced Materials |
| Volume | 30 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 25 2018 |
Funding
H.L. and Q.L. contributed equally to this work. Q.L. and J.W. (in situ TEM and interpretation), Z.Y. and C.W. (DFT calculation), L.L. and M.H. (battery measurements), and V.P.D. (TEM interpretation) were supported as part of the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences under Award # DEAC02-06CH11357. Q.L., J.W., and V.P.D. were also supported by the Samsung Advanced Institute of Technology (SAIT)’s Global Research Outreach (GRO) Program and the Initiative for Sustainability and Energy at Northwestern (ISEN). Portions of this work were performed in the NUANCE Center at Northwestern University, using the EPIC facility that receives support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. The authors gratefully acknowledge computing resources from: (1) the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract DE-AC02-05CH11231; (2) Blues, a high-performance computing cluster operated by the Laboratory Computing Resource Center at Argonne National Laboratory.
Keywords
- Cu-doping transition metal oxides
- cycling stability
- in situ transmission electron microscopy (TEM)
- lithium-ion batteries
ASJC Scopus subject areas
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering
