Ultra-rapid combustion synthesis of Na2FePO4F fluorophosphate host for Li-ion and Na-ion insertion

Exploring soft-chemistry synthesis of Fe-based battery cathode materials, we have optimized combustion synthesis as an ultra-rapid approach to produce Na 2 FePO 4 F fluorophosphate cathode. It yields nanoscale, carbon-coated target product by annealing (at 600 °C) for just 1 min. The purity of the material crystallizing in the orthorhombic structure was confirmed by powder X-ray diffraction pattern and XPS analysis, while the morphology was studied by scanning electron microscopy. The as-synthesized material exhibits good electrochemical performance delivering a first discharge capacity of more than 70 mAh/g at C/10 rate versus both Li + /Li and Na + /Na, hence acting as an efficient host for both Li-ion and Na-ion insertion. Combustion synthesis can be employed as an economic route for synthesis and rapid screening of various phosphate-based insertion materials.