journal contribution posted on 2016-03-04, 00:00 authored by U. Boesenberg, M.A. Marcus, A.K. Shukla, T. Yi, E. McDermott, P.F. Teh, M. Srinivasan, A. Moewes, J. Cabana
Electrochemical conversion reactions of transition metal compounds create opportunities for large energy storage capabilities exceeding modern Li-ion batteries. However, for practical electrodes to be envisaged, a detailed understanding of their mechanisms is needed, especially vis-à-vis the voltage hysteresis observed between reduction and oxidation. Here, we present such insight at scales from local atomic arrangements to whole electrodes. NiO was chosen as a simple model system. The most important finding is that the voltage hysteresis has its origin in the differing chemical pathways during reduction and oxidation. This asymmetry is enabled by the presence of small metallic clusters and, thus, is likely to apply to other transition metal oxide systems. The presence of nanoparticles also influences the electrochemical activity of the electrolyte and its degradation products and can create differences in transport properties within an electrode, resulting in localized reactions around converted domains that lead to compositional inhomogeneities at the microscale.
This work was primarily supported by the Assistant Secretary for Energy Efficiency and
Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy (DOE)
under Contract No. DE-AC02-05CH11231, as part of the Batteries for Advanced
Transportation Technologies (BATT) Program. Exceptions to this statement are as follows.
TY was supported as part of the Joint Center for Energy Storage Research, an Energy
Innovation Hub funded by the U.S. DOE, Office of Science, Basic Energy Sciences. EM and
AM wish to acknowledge funding from the Natural Sciences and Engineering Research
Council (NSERC) and the Canada Research Chair program. P.F. Teh grateful acknowledges
the World Future Foundation (WFF) for PhD Prize in Environmental and Sustainability
Research@NTU 2014. The m-XAS work was conducted at the Advanced Light source which
is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S.
DOE under Contract No. DE-AC02-05CH11231. The operando XAS experiments were
carried out at the Stanford Synchrotron Radiation Lightsource, a Directorate of SLAC
National Accelerator Laboratory and an Office of Science User Facility operated for the U.S.
DOE Office of Science by Stanford University. The SSRL Structural Molecular Biology
Program is supported by the DOE Office of Biological and Environmental Research, and by
the National Institutes of Health, National Institute of General Medical Sciences (including
P41GM103393) and the National Center for Research Resources (P41RR001209).
Supporting ex situ XAS was carried out at the Pacific Northwest Consortium-X-ray Science
Division (PNC/XSD) facilities at the Advanced Photon Source (APS), supported by the U.S.
DOE Office of Science, the Canadian Light Source (CLS) and its funding partners, the
University of Washington, and the APS. Use of the APS, an Office of Science User Facility
operated for the DOE by Argonne National Laboratory, was supported by Contract No.
Publisher StatementThis is the copy of an article published in Scientific Reports © 2014 Nature Publishing Group. Scientific Reports. 2014. 4. DOI: 10.1038/srep07133.
PublisherNature Publishing Group