Insights into the electrochemical activity of nanosized α-LiFeO2
- 作者：J. Morales ; J. Santos-Peñ ; a ; R. Tró ; coli ; S. Franger ; E. Rodrí ; guez-Castelló ; n
- 关键词：
//www.sciencedirect.com/scidirimg/entities/204e.gif" alt="greek small letter alpha" title="greek small letter alpha" border="0">-LiFeO2 ; Lithium ion batteries positive electrode ; X-ray photoelectron spectroscopy ; Mö ; ssbauer s
- 刊名：Electrochimica Acta
- 出版年：2008
- 期刊代码：30_00134686
- 类别：ch
- 出版时间：20 September 2008
- 卷：53
- 期：22
- 页码：6366-6371
- 文件大小：570 K
摘要
In recent work [J. Morales, J. Santos-Peña, Electrochem. Commun. 9 (2007) 2116], we prepared nanosized 
-LiFeO2 with increased electrochemical activity in lithium cells relative to various lithium ferrite polymorphs. In this work, we studied the previous electrodes in different charge states in order to obtain a more accurate picture of the phenomena occurring during cycling. Ex situ X-ray photoelectron spectroscopy (XPS) measurements confirmed the oxidation/reduction of iron atoms during the charge/discharge process. The electrochemical impedance spectroscopy results suggested that the electrolyte is not oxidised during the first charge, but rather than a solid electrolyte interface is formed after one cycle. Also, thermal tests revealed that Fe(IV) present in the electrodes reacted with the electrolyte to form oxidised carbon species. Finally, -LiFeO2 was tested as a positive electrode material in a lithium battery under different regimes. Stabilised capacities up to 150 mAh g−1 were obtained under a C/4 regime. This lithium ferrite is therefore an attractive alternative to LiCoO2.
-LiFeO2 with increased electrochemical activity in lithium cells relative to various lithium ferrite polymorphs. In this work, we studied the previous electrodes in different charge states in order to obtain a more accurate picture of the phenomena occurring during cycling. Ex situ X-ray photoelectron spectroscopy (XPS) measurements confirmed the oxidation/reduction of iron atoms during the charge/discharge process. The electrochemical impedance spectroscopy results suggested that the electrolyte is not oxidised during the first charge, but rather than a solid electrolyte interface is formed after one cycle. Also, thermal tests revealed that Fe(IV) present in the electrodes reacted with the electrolyte to form oxidised carbon species. Finally, -LiFeO2 was tested as a positive electrode material in a lithium battery under different regimes. Stabilised capacities up to 150 mAh g−1 were obtained under a C/4 regime. This lithium ferrite is therefore an attractive alternative to LiCoO2.