화학공학소재연구정보센터
Journal of Power Sources, Vol.359, 234-241, 2017
Discharge products of ionic liquid-based Li-O-2 batteries observed by energy dependent soft x-ray transmission microscopy
Products deposited on an O-2-cathode discharged in ionic liquid electrolytes are analyzed by transmission soft X-ray microscopy (TXM) and compared to ether-based electrolytes, showing differences in morphology and chemical compositions. With both solvents we observe Li2O2 and LiO2 primary products in similar proportions. However, while as previously observed in tetraglyme an important reactivity takes place producing significant amount of carbonates, in ionic liquid-based electrolytes the formation of carbonates was almost negligible, confirming higher stability. Only when sample is intentionally air exposed before analysis, significant amounts of carbonates came up. However, LiOH crystallites are clearly recognized with the ionic liquid electrolyte. The abundance of these crystallites depends on both the LiTFSI concentration and the storage time of discharged electrodes, suggesting that they result from the reaction of water trace with primary discharge products. (C) 2017 Elsevier B.V. All rights reserved.