Fabrication of Na2FeP2O7 glass-ceramics for sodium ion battery

New cathode candidate Na2FeP2O7 for rechargeable sodium ion second battery was successfully prepared by glass-ceramics method. The precursor glass, which is same composition in Na2FeP2O7, was prepared by melt-quenching method. Na2FeP2O7 was obtained by heat treatment of precursor glass powder with 10% glucose addition as reduction agent of Fe3+ at 620°C for 3 h in electric furnace. Na2FeP2O7 has triclinic P1-structure with a = 0.64061 nm, b = 0.938893 nm, c = 1.09716 nm, α = 64.5381°, β = 86.0580°, γ = 73.0619°. By means of electrochemical charge–discharge testing, Na2FeP2O7 exhibits 2.9 V, 88 mAh/g, in which is 90% for the theoretical capacity during 2.0–3.8 V cut-off voltages. Na2FeP2O7 ceramics has the potential for the safety cathode candidate for the sodium ion battery with a low materials cost.