Abstract
Platinum (Pt) thin films are useful in applications requiring high-conductivity electrodes with excellent thermal and chemical stability. Ultrasmooth and epitaxial Pt thin films with single-crystalline domains have the added benefit of providing ideal templates for the subsequent growth of heteroepitaxial structures. Here, we grow epitaxial Pt (111) electrodes (ca. 30 nm thick) on sapphire (α-Al2O3 (0001)) substrates with pulsed laser deposition. This versatile technique allows control of the growth process and fabrication of films with carefully tailored parameters. X-ray scattering, atomic-force microscopy, and electron microscopy provide structural characterization of the films. Various gaseous atmospheres and temperatures were explored to achieve epitaxial growth of films with low roughness. A two-step (500 °C/300 °C) growth process was developed, yielding films with improved epitaxy without compromising roughness. The resulting films possess ultrasmooth interfaces (<3 Å) and high electrical conductivity (6.9 × 106 S/m). Finally, Pt films were used as current collectors and templates to grow lithium manganese oxide (LiMn2O4 (111)) epitaxial thin films, a cathode material used in Li-ion batteries. Using a solid-state ionogel electrolyte, the films were highly stable when electrochemically cycled in the 3.5-4.3 V vs Li/Li+ range.
Original language | English (US) |
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Pages (from-to) | 1921-1929 |
Number of pages | 9 |
Journal | ACS Applied Materials and Interfaces |
Volume | 16 |
Issue number | 1 |
DOIs | |
State | Published - Jan 10 2024 |
Funding
This research was primarily supported by the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, and Basic Energy Sciences (Grant No. DE-AC02-06CH11357) and partially funded by DOE/BES Award No. DE-SC0023450 to the Hydrogen in Energy and Information Sciences EFRC at NU. This work made use of the NU X-ray Diffraction Facility, the Pulsed Laser Deposition Facility, and the NUANCE Center, which have received support from the MRSEC program of the National Science Foundation (Grant No. DMR-2308691) at the Materials Research Center of Northwestern University, the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (Grant No. NSF ECCS-2025633) and the IIN.
Keywords
- 4D-STEM
- epitaxy
- lithium manganese oxide
- lithium-ion battery
- platinum
- pulsed laser deposition
ASJC Scopus subject areas
- General Materials Science