Structural and electrochemical diversity in LiFe1-δZn δSO4F solid solution: A Fe-Based 3.9 v positive-electrode material

Transition-metal fluorosulfates are currently under intense investigation for their use as anodes in Li-ion batteries. The substitution of Zn into LiFeSO4F has been found to trigger a transition from the tavorite structure to two separate polymorphs which crystallize in the sillimanite and triplite structures (see picture). These new phases show Fe2+/Fe 3+ redox potentials of 3.6 and 3.9 V versus Li, respectively. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim