fig3

Figure 3. (A) Crystal structures of FeF₃, FeF₂, FeF₃·0.33H₂O, and FeF₃·0.5H₂O. This figure is quoted with permission from Liu et al. (ReO₃-type and HTB-type)^[19], Huang et al. (Rutile-type)^[25], and Rao et al. (Pyrochlore-type)^[34]. (B) Reaction pathways for both discharging and charging of the FeF₃ electrode and their crystal structures. These summaries are based on the empirical data and DFT calculation results, where Li, Fe, and F atoms are represented by green, blue, and red spheres. This figure is quoted with permission from Li et al.^[21]. (C) Performance during cycling of FeF₂@CNT under different current densities, which shows cycling stability and rate performance of FeF₂@CNT. This figure is quoted with permission from Zhou et al.^[27]. (D) Voltage vs. capacity profiles of FeF₃·0.33H₂O electrodes for the first ten cycles with a current density of 14 mA g^-1. This figure is quoted with permission from Li et al.^[32]. (E and F) Voltage vs. capacity profiles of FeF₃·0.5H₂O cathodes wired by 5 wt % SWNTs at 0.1 C during the first few cycles (vs. Li/Na Anode, respectively). This figure is quoted with permission from Li et al.^[29].