A one-step, facile supercritical-ethanol-fluid synthesis of Se-modified Ru nanoparticles nucleated on carbon defects is reported, and it is demonstrated that these nanoparticles provide, with >70% efficiency at 1 A g−1, a highly active and reversible oxygen-reduction/oxygen-evolution reaction on an air cathode in a nonaqueous electrolyte. The Se modification not only prevents Ru oxidation during charge/discharge cycling, but also improves the catalytic activity by promoting Li2O2 versus Li2O deposited on the Ru particles during discharge. A computational calculation with density functional theory supports the role of a larger electron transfer to the oxygen of Li2O2 adsorbed on a surface layer of RuSe2−δ than on a surface layer of RuO2, thereby shifting the more stable adsorbent from Li2O to Li2O2.
Bibliographical noteFunding Information:
J.-H.J. and E.L. contributed equally to this work. This work was supported by the program “Materials and Interfacial Chemistry for Next Generation Electrical Energy Storage” funded by the U.S. Department of Energy (DESC0005397), Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2009) and Welch Foundation (F-1841). The authors give special thanks to CCRF for TEM, NCIRF for ICP-AES, and TMI for XPS measurements.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)