| Functionalization of nanosheets
by electrochemistry |
| MnO2 nanosheets are colored and bleached
by electrochemical insertion and extraction of lithium ions,
respectively, with high coloration efficiency. Moreover, the
optical density of the multi-layered nanosheets is accurately
proportional to the number of the layers (left) and can be
precisely controlled by the amount of the inserted lithium
ions (right). |
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| Ionic materials built up from
nanosheets |
 Layered
LiMnO2 will be cheap and environmentally benign electrode
material in lithium-ion batteries. However, it easily transforms
into spinel phase upon the cycling due to their structural
similarity, which results in rapid capacity fading. A new
LiMnO2 built up from turbostratically stacked MnO2 nanosheets
retains large capacity, because its different oxygen alignment
from spinel phase prevents the transformation.
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| High-performance ionic devices |
| Solid-state battery is a fundamental
solution to the safety issue of lithium-ion batteries containing
combustible electrolytes; however, its energy and power densities
are not high enough for its practical use. Our unique construction,
in which two kinds of solid electrolytes are used, has made
its energy density comparable to commercialized batteries. |
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