Journal
NATURE MATERIALS
Volume 20, Issue 1, Pages 76-83Publisher
NATURE PORTFOLIO
DOI: 10.1038/s41563-020-0756-y
Keywords
-
Categories
Funding
- National Science Foundation of China [11504192, 51804173, 11434006, 51673103]
- National Basic Research Program of China [2015CB921502]
- National Key RAMP
- D Program of China [2017YFA0303604]
- National Science Foundation of Shandong Province [ZR2018BB030]
- Science and Technology Program in Qingdao City [18-2-2-22-jch, 16-5-12-jch]
- Youth Innovation Promotion Association of the Chinese Academy of Sciences [2018008]
- Welch Foundation [F-1861]
- Sloan Research Fellowship
- Camille Dreyfus Teacher-Scholar award
- Natural Sciences and Engineering Research Council of Canada [RGPIN-04178]
- Canada First Research Excellence Fund
- National Science Foundation of the United States [DMR 1700137]
- Office of Naval Research of the United States [N00014-16-1-2657]
Ask authors/readers for more resources
Although some transition metal oxide-based electrodes exhibit high storage capacities beyond theoretical values, the surface capacitance on metal nanoparticles involving spin-polarized electrons is consistent with a space charge mechanism. The phenomenon of anomalously high storage capacities in different metal oxides is still under debate, but in situ magnetometry has shown that surface capacitance plays a dominant role in providing extra capacity. This space charge mechanism can be generalized to a broad range of transition metal compounds, providing guidance for advanced energy storage systems.
Although some transition metal oxide-based electrodes exhibit high storage capacities beyond theoretical values, the underlying physicochemical mechanism remains elusive. Surface capacitance on metal nanoparticles involving spin-polarized electrons is now shown to be consistent with a space charge mechanism. In lithium-ion batteries (LIBs), many promising electrodes that are based on transition metal oxides exhibit anomalously high storage capacities beyond their theoretical values. Although this phenomenon has been widely reported, the underlying physicochemical mechanism in such materials remains elusive and is still a matter of debate. In this work, we use in situ magnetometry to demonstrate the existence of strong surface capacitance on metal nanoparticles, and to show that a large number of spin-polarized electrons can be stored in the already-reduced metallic nanoparticles (that are formed during discharge at low potentials in transition metal oxide LIBs), which is consistent with a space charge mechanism. Through quantification of the surface capacitance by the variation in magnetism, we further show that this charge capacity of the surface is the dominant source of the extra capacity in the Fe3O4/Li model system, and that it also exists in CoO, NiO, FeF(2)and Fe2N systems. The space charge mechanism revealed by in situ magnetometry can therefore be generalized to a broad range of transition metal compounds for which a large electron density of states is accessible, and provides pivotal guidance for creating advanced energy storage systems.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available