Chueh-Han Wang, Yu-wen Yeh, Nithinai Wongittharom
Jan 15, 2015
Citations
0
Influential Citations
85
Citations
Quality indicators
Journal
Journal of Power Sources
Abstract
Abstract Orthorhombic Na 0.44 MnO 2 with wide structural tunnels for sodium ion transport is synthesized. Butylmethylpyrrolidinium-bis(trifluoromethanesulfonyl)imide (BMP-TFSI) ionic liquid (IL) with various Na solutes, namely NaBF 4 , NaClO 4 , NaTFSI, and NaPF 6 , is used as an electrolyte for rechargeable Na/Na 0.44 MnO 2 cells. The cell with NaClO 4 -incorporated IL electrolyte exhibits superior charge–discharge performance due to it having the lowest solid–electrolyte-interface resistance and charge transfer resistance at both the Na and Na 0.44 MnO 2 electrodes. The IL electrolyte shows high thermal stability and is suitable for use at an elevated temperature. At 75 °C, the measured capacity of Na 0.44 MnO 2 in the IL electrolyte with NaClO 4 is as high as 115 mAh g −1 (at 0.05 C), which is close to the theoretical value (121 mAh g −1 ). Moreover, 85% of this capacity can be retained when the charge–discharge rate is increased to 1 C. These properties are superior to those of a conventional organic electrolyte.