Single-Step Synthesis of FeSO4F1鈥?i>yOHy (0 鈮?y 鈮?1) Positive Electrodes for Li-Based Batteries

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• 作者：M. Ati ; M-T. Sougrati ; G. Rousse ; N. Recham ; M-L. Doublet ; J-C. Jumas ; J-M. Tarascon
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：April 24, 2012
• 年：2012
• 卷：24
• 期：8
• 页码：1472-1485
• 全文大小：846K
• 年卷期：v.24,no.8(April 24, 2012)
• ISSN：1520-5002

文摘

The recent discovery of electrochemical activity at 3.6 V vs Li⁺/Li⁰ in LiFeSO₄F has generated widespread research activity in this new family of fluorosulfate electrode materials aiming at either increasing the Fe³⁺/Fe²⁺ redox potential, searching for new active members, or extending this family to hydroxyl-fluorosulfates. Here we present a new low temperature single step synthesis of FeSO₄F_1鈥?i>yOH_y phases using FeF₃ and Fe₂(SO₄)₃路nH₂O as precursors. Using thorough chemical analytical techniques to test for F鈥?/sup> content in conjunction with M枚ssbauer measurements, we demonstrate the existence of a limited solid solution (0.35 < y<1) within this system. Members pertaining to this solid solution have a redox activity ranging from 3.2 to 3.6 V vs Li⁺/Li⁰ and show sustained reversible capacity retention of 130 mAh/g which makes them potentially interesting for Li-based polymer batteries. We demonstrate that the Li-insertion-deinsertion mechanism depends markedly on the sample F鈥?/sup>content by using joint in situ XRD and M枚ssbauer spectroscopy. Moreover, we show the versatility of our synthetic approach by extending it to the elaboration of Fe_1鈥?i>zM_zSO₄F_1鈥?i>yOH_y phases with M = Ti and V.

Keywords:

batteries; fluorosulphate electrodes; hydroxyl-fluorosulfates