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Title: Single-Step Synthesis of FeSO4F1-yOHy (0 ≤ y ≤ 1) Positive Electrodes for Li-Based Batteries

Journal Article · · Chemistry of Materials
DOI:https://doi.org/10.1021/cm300188a· OSTI ID:1039069

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 FeSO4F1-yOHy phases using FeF3 and Fe2(SO4)3 ∙ nH2O as precursors. Using thorough chemical analytical techniques to test for F- content in conjunction with Moessbauer 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- content by using joint in situ XRD and Moessbauer spectroscopy. Moreover, we show the versatility of our synthetic approach by extending it to the elaboration of Fe1-zMzSO4F1-yOHy phases with M = Ti and V.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
DOE - BASIC ENERGY SCIENCES
OSTI ID:
1039069
Journal Information:
Chemistry of Materials, Vol. 24, Issue (8) ; 04, 2012; ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
ENGLISH