Cathode properties of amorphous and crystalline FePO4

Lithium intercalation into amorphous FePO4 cathode in aqueous solutions

“…The slurry was evaporated at 90 °C for 30 min and the resultant precursor was fine ground and calcined at 200 °C for 12 h to yield the amorphous FePO 4 material. The Fe 3+ / 2+ redox couple in the amorphous iron phosphate is reported [17] to be fully reversible than the crystalline counterpart. The crystalline FePO 4 phase is known to be electrochemically inactive [18].…”

“…The amorphous iron phosphate (FePO 4 ) material used in this work was synthesized by a simple and inexpensive method identical to that described by Okada et al [17]. The stoichiometric ratios of starting materials such as metallic iron and P 2 O 5 were mixed in ethanol for an hour in an agate mortar.…”

Precipitation of Iron and Aluminum Phosphates Directly from Aqueous Solution as a Function of Temperature from 50 to 200 °C

“…37 Strengite and phosphosiderite can be synthesized by either acid reflux or boiling 17,43 or at hydrothermal conditions. 44 The main industrial application of hydrated iron phosphates is their use as cathodes in Li batteries, [45][46][47][48] while giniite is used as a potential dehydrogenation catalytic material. Despite this past work, our understanding of the nucleation, growth, and transformation of Al and Fe phosphate minerals is still fragmented.…”

Bio-Inspired Synthesis of Electrode Materials for Lithium Rechargeable Batteries

“…Figure 7 represents the M13 virus genetically modified to bind amorphous FePO 4 cathode material and highly conductive carbon nanotubes (CNTs) (Lee et al, 2009). Amorphous FePO 4 is an attractive cathode material due to its high specific capacity and safety originating from the strong (PO 4 ) 3-covalent bond, but its poor electronic/Li-ionic conduction precludes further investigation (Okada et al, 2005). Therefore, developing nano-sized amorphous FePO 4 with a highly conductive agent is essential for the high performance Li rechargeable battery.…”

“…Another purpose for the heat treatment is to remove crystal water because it tends to form a hydrated phase of FePO 4 ·2H 2 O when the FePO 4 phase is synthesized from aqueous solution. Heat treatment at too high temperature induces the crystallization of the amorphous phase, lowering the electrochemical activity (Okada et al, 2005). Thus, controlling the temperature is an important factor for the heat treatment.…”