Testing Mg as an anode against BiF_3 and SnF_2 cathodes for room temperature rechargeable fluoride ion batteries

摘要

In the attempt of developing post-lithium technologies for electrochemical energy storage devices, rechargeable batteries based on fluoride shuttle have recently attracted attention due to the perspective of achieving high energy densities. In this study, we present relatively high voltage room temperature rechargeable fluoride ion batteries (FIBs) using a liquid electrolyte. FIBs were built using LiPF6 as an electrolyte, Mg + MgF2 as an anode, and BiF3 and SnF2 as cathodes. We have investigated two types of FIB systems such as Mg+MgF2/LiPF6/BiF3, and Mg+MgF2/LiPF6/SnF2 at room temperature. The electrochemical analyzes were performed on sealed steel case coin cells containing a FIB pellet. A current density of 38 mu A cm(-2) was applied. First discharge capacities of 160 and 185 mA.h.g(-1) were obtained for the Mg+MgF2/LiPF6/BiF3 and Mg+MgF2/LiPF6/SnF2 electrochemical systems, respectively. The reaction mechanisms of these FIBs were investigated by X-ray diffraction, impedance measurements, cyclic voltammetry and constant current battery cycling. (C) 2019 Elsevier B.V. All rights reserved.