| Autor: |
Il Woo Ock, Kyung Min Choi, Dong Ki Lee, Hyung Mo Jeong, Renjia Zhou, Delia J. Milliron, William A. Goddard, Tao Cheng, Jeung Ku Kang |
| Rok vydání: |
2015 |
| Předmět: |
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| Zdroj: |
Proceedings of the National Academy of Sciences of the United States of America. 112(26) |
| ISSN: |
1091-6490 |
| Popis: |
Nanocrystals are promising structures, but they are too large for achieving maximum energy storage performance. We show that rescaling 3-nm particles through lithiation followed by delithiation leads to high-performance energy storage by realizing high capacitance close to the theoretical capacitance available via ion-to-atom redox reactions. Reactive force-field (ReaxFF) molecular dynamics simulations support the conclusion that Li atoms react with nickel oxide nanocrystals (NiO-n) to form lithiated core–shell structures (Ni:Li_2O), whereas subsequent delithiation causes Ni:Li_2O to form atomic clusters of NiO-a. This is consistent with in situ X-ray photoelectron and optical spectroscopy results showing that Ni^(2+) of the nanocrystal changes during lithiation–delithiation through Ni^0 and back to Ni^(2+). These processes are also demonstrated to provide a generic route to rescale another metal oxide. Furthermore, assembling NiO-a into the positive electrode of an asymmetric device enables extraction of full capacitance for a counter negative electrode, giving high energy density in addition to robust capacitance retention over 100,000 cycles. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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