Nanoparticle iron-phosphate anode material for Li-ion battery

Abstract

Nanoparticle crystalline iron phosphates (${\mathrm{FePO}}_4\bullet 2{\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{FePO}}_4$ ) were synthesized using a (CTAB) surfactant as an anode material for Li rechargeable batteries. The electrochemical properties of the nanoparticle iron phosphates were characterized with a voltage window of 2.4–0 V. A variscite orthorhombic ${\mathrm{FePO}}_4\bullet 2{\mathrm{H}}_2\mathrm{O}$ showed a large initial charge capacity of $609\mathrm{mAh}∕\mathrm{g}$ . On the other hand, a tridymite triclinic ${\mathrm{FePO}}_4$ exhibited excellent cyclability: the capacity retention up to 30 cycles was $\sim 80\%$ , from 485 to $375\mathrm{mAh}∕\mathrm{g}$ . The iron phosphate anodes exhibited the highest reported capacity, while the cathode ${\mathrm{LiFePO}}_4$ has an ideal capacity of $170\mathrm{mA}\mathrm{h}∕\mathrm{g}$ .