摘要： It is desirable to develop electrode materials for advanced rechargeable batteries with low cost, long life, and high-rate capability. Pyrite FeS 2 , as an easily obtained natural mineral, has been already commercialized in primary lithium batteries, but encountered problems in rechargeable batteries with carbonate-based electrolytes due to the limited cycle life caused by the conversion-type reaction (FeS 2 + 4M → Fe + 2M 2 S (M = Li or Na)). Herein, we demonstrate that FeS 2 microspheres can be applied in room-temperature rechargeable sodium batteries with only the intercalation reaction by simultaneously selecting a compatible NaSO 3 CF 3 /diglyme electrolyte and tuning the cut-off voltage to 0.8 V. A surprisingly high-rate capability (170 mA h g −1 at 20 A g −1 ) and unprecedented long-term cyclability (∼90% capacity retention for 20 000 cycles) has been obtained. We suggest that a stable electrically conductive layer-structured Na x FeS 2 was formed during cycling, which enables the highly reversible sodium intercalation and deintercalation. Moreover, 18650-type sodium batteries were constructed exhibiting a high capacity of ∼4200 mA h (corresponding to 126 W h kg −1 and 382 W h L −1 ) and a capacity retention of 97% after an initial 200 cycles at 4 A during charge-discharge. This shows that the production of rechargeable sodium batteries with FeS 2 microspheres is viable for commercial utilization. High-performance rechargeable Na/FeS 2 batteries showing only the intercalation reaction are obtained by selecting a NaSO 3 CF 3 /diglyme electrolyte and tuning the cut-off voltage to 0.8 V. 出版日期： 2015-04-01 資源來源： Royal Society of Chemistry 識別號： ISSN: 1754-5692 識別號： EISSN: 1754-5706 識別號： DOI: 10.1039/c4ee03759f
