Стабільні кремнієві електроди з полівініліденфторид-зв’язуючим для літій-іонних акумуляторів
Replacing intercalated graphite in traditional lithium-ion batteries with conversion silicon anode material gives an advantage in increasing specific energy at a lower price. A significant drawback of silicon is its very large swelling when saturated with lithium, with the growth of mechanical loads...
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| Datum: | 2020 |
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| Hauptverfasser: | , , , |
| Format: | Artikel |
| Sprache: | Ukrainisch |
| Veröffentlicht: |
Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2020
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| Schlagworte: | |
| Online Zugang: | https://www.cpts.com.ua/index.php/cpts/article/view/532 |
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| Назва журналу: | Chemistry, Physics and Technology of Surface |
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Chemistry, Physics and Technology of Surface| Zusammenfassung: | Replacing intercalated graphite in traditional lithium-ion batteries with conversion silicon anode material gives an advantage in increasing specific energy at a lower price. A significant drawback of silicon is its very large swelling when saturated with lithium, with the growth of mechanical loads in the bulk of the electrode layer. Direct use of silicon, even nanoscale, is impossible without modifying the interface of the "silicon | electrolyte". A stable cycling is shown of silicon electrodes based on the nanocomposite Si@SiOC&C (0D ? micro-3D) with a high silicon content (9nano-S@1SiOC&C by mass), active electrically conducting additive of synthetic graphite KS6 and vinylidene fluoride polymer binder in traditional ethylene carbonate electrolyte. The effect is discussed of carbon-enriched silicon oxycarbide (glass-like carbon) – SiOC&C, as a modifier of the "silicon | electrolyte" interface, synthesized using polymethylphenylsiloxane, on their electrochemical behavior. Formation of structurally-integrated phase boundary in the synthesis of the composite, the high mechanical strength of the glass-like carbon, the capability of SiOC&C to set up a relatively large amount of lithium in its bulk and a low electrocatalytic activity of this material in relation to organic electrolyte allows to accommodate without cracking the volume changes of silicon, solving the problem of preventing destruction carbon coating of active nanoparticles during long-term cycles of silicon electrodes. Glass-like carbon material can also contribute to the phase transition of the cubic ?-Li15Si4, with the formation of which the volume of the original silicon increases by 280 %, to a denser ortorombic ?-Li15Si4, with a smaller increase in silicon volume (by 210 %). Therefore, the usual vinylidene fluoride polymer binder for graphite anode of lithium-ion batteries can provide effective electrical contact between the particles of the active silicon material and the current collector. These electrodes are effective for use in high-energy lithium-ion superbatteries. |
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