The electrochemical reaction mechanism of pyrite FeS2 as Cathode for Room Temperature Sodium-Sulfur Battery

• Main Authors: Chang, Po-Chia, 張博嘉
• Other Authors: Chen, Chia-Chun
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/71292640543441077898

碩士 === 國立臺灣師範大學 === 化學系 === 103 === Efficient electrical energy storage has attracted intense attention due to power demend in next generation of electric vehicles and stationary applications. Rechargeable battery has viewed as good approach for energy storage. To aspire the higher energy density than traditional lithium ion battery used wildly, room temperature sodium-sulfur batteries (RT Na-S batteries) are especially attractive because of their high specific energy. In this thesis, a iron pyrite FeS2 material was investigated as sulfur source in the cathode electrode of RT Na-S battery. We found that iron disulfide as cathode materials (FeS2/Na-S battery) exhibited first discharge and charge capacity of 1360 mAhg-1 and 1086 mAhg-1 at a current density of 50 mAg-1 with a suitable electrolyte and potential range. The irreversible capacity at first cycle is approximately 20%. The capacity of FeS2 still remained 745 mAh g-1 after 50th cycles. During rapid charge - discharge test, FeS2/Na-S battery showed a high capacity of 520 mAh g-1 at a current density of 8920 mAg-1. In the detailed characterization by Raman and X-ray absorption spectra, we found that No polysulfide was formed by sulfur in FeS2 reacting with sodium and dissolved in electrolyte, resulting in remaining good capacity retention. Overall results indicated that The FeS2 cathode materials used in RT Na-S battery exhibited long cycle performance, high Coulombic efficiency and good capacity retention at high charge-discharge rate.