Abstract
Sodium-Ion Batteries (SIBs) present a promising alternative to Lithium-Ion Batteries (LIBs) due to their similar physicochemical properties, abundant natural resources, and cost-effectiveness. However, their lower energy density compared to LIBs limits their widespread application. This research addresses this challenge through two strategies: enhancing electrode capacity and increasing cell voltage.In the first study, a novel bifunctional crosslinked binder is fabricated to enhance the performance of hard carbon (HC) anodes, thereby increasing the energy density of full cells. The binder, formed by crosslinking sodium alginate (SA) and carboxymethyl cellulose (CMC) with Ca(TFSI)2, demonstrates a high initial coulombic efficiency (ICE) of 89.2% and superior capacity retention of 98.6% after 600 cycles at 500 mA/g. This binder's three-dimensional network facilitates efficient sodium ion transport, supporting high mass loading HC anodes without sodium plating issues. Full cells using this crosslinked binder show better capacity retention (68%) compared to those with commercial binders. The second study focuses on a high-voltage tolerant ether electrolyte, incorporating dual additives Al(acac)3 and FEC, which form a stable cathode-electrolyte interphase (CEI) layer. This layer enables high voltage applications, as demonstrated by the NVP║Na cell, which retains 93.6% capacity after 300 cycles at a 1C rate and achieves a high discharge capacity of 73.5 mAh/g at a 20C rate without sacrificing performance.
Together, these studies offer significant advancements in enhancing the energy density of SIBs through innovative approaches.
| Date of Award | 2025 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Minhua SHAO (Supervisor) |
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