fig4

Figure 4. (A) Crystal structures of LiVPO₄F, NaFePO₄F, and Na₂FePO₄F. (B) Electrochemical curves of LiVPO₄F/C composite cycled vs. Li⁺/Li starting in discharge show Li-ion insertion/extraction potential (as shown by the red arrow). This figure is quoted with permission from Ellis et al.^[42]. (C) The characteristic discharge profiles of the 5 wt% ZrO₂ coated Li₂CoPO₄F cathode materials between 2 and 5.2 V at various rates. This figure is quoted with permission from Amaresh et al.^[48]. (D) The charge-discharge curves of NaVPO₄F obtained from different synthesis processes at 15 mA g^-1. This figure is quoted with permission from Xu et al.^[49]. (E) Charge-discharge curves of Na₃V₂PO₄F₃/C. This figure is quoted with permission from Zou et al.^[52]. (F) The initial charge/discharge profile of Li_0.995K_0.005VPO₄F at 0.12 C (1 C = 156 mA g^-1) in the potential range of 2.5-4.6 V (vs. Li⁺/Li). The inset shows the CV curves at a scanning rate of 0.1 mV s^-1. This figure is quoted with permission from Wu et al.^[58].