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Identifying the Electrochemical Processes in LiFeSO 4 F Cathodes for Lithium Ion Batteries
Author(s) -
Blidberg Andreas,
Sobkowiak Adam,
Tengstedt Carl,
Valvo Mario,
Gustafsson Torbjörn,
Björefors Fredrik
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201700192
Subject(s) - pedot:pss , electrochemistry , materials science , coating , lithium (medication) , electrode , cathode , chemical engineering , conductive polymer , battery (electricity) , composite number , polymer , electrochemical kinetics , ion , diffusion , nanotechnology , composite material , chemistry , organic chemistry , thermodynamics , medicine , power (physics) , physics , endocrinology , engineering
The electrochemical performance of tavorite LiFeSO 4 F can be considerably improved by coating the material with a conducting polymer (poly(3,4‐ethylenedioxythiophene); PEDOT). Herein, the mechanisms behind the improved performance are studied systematically by careful electrochemical analysis. It is shown that the PEDOT coating improves the surface reaction kinetics for the Li‐ion insertion into LiFeSO 4 F. For such coated materials no kinetic limitations remain, and a transition from solid state to solution‐based diffusion control was observed at 0.6 mA cm −2 ( circa C/2). Additionally, the quantity of PEDOT is optimized to balance the weight added by the polymer and the improved electrochemical function. Post mortem analysis shows excellent stability for the LiFeSO 4 F‐PEDOT composite, and maintaining the electronic wiring is the most important factor for stable electrochemical cycling of LiFeSO 4 F. The insights and the methodology used to determine the rate‐controlling steps are readily transferable to other ion‐insertion‐based electrodes, and the findings are important for the development of improved battery electrodes.