The nickel-nickel oxide [Ni-NiO1+x(0 less than or equal to x < 0.5)] composites prepared from a mixture of Ni and LiNiO2 or NiO powders at 900 &DEG;C under 2000 atm for 2 h by hot isostatic pressing were employed as the anode for electrolytic production of NF3. In electrolysis of a molten NH4F&BULL;2HF with and without LiF at 100 &DEG;C and at 25 mA/cm(2), the anode gas generated at the Ni-NiO1+x composite anode was composed of N-2, O-2, NF3, N2F2, N2F4, and N2O, and its composition was almost the same as that at the Ni sheet anode. The current efficiency for NF3 formation on the Ni-NiO composite anode from mixture of NiO and Ni powders was high compared with that on the Ni-NiO1+x composite anode from the mixture of LiNiO2 and Ni powders. The best current efficiency for NF3 formation was ca. 53% on the Ni 5 mol % NiO composite anode, and it was almost the same as that of the Ni sheet anode. The addition of LiF in a molten NH4F&BULL;2HF increased it, presumably because of deposition of Li2NiF6 on the anode. On the other hand, the anode consumption of the Ni-NiO composite was much smaller compared with that of the Ni sheet electrode. Also, the oxygen content in the oxidized layer formed on the Ni-NiO composite anode was high compared with that on the Ni sheet anode. The scanning electron microscope observation revealed that the surface of the Ni-NiO composite anode was covered with the compact film having some defects. From these results, it is concluded that the Ni-NiO composite anode is favorable for electrolytic production of NF3, and that the oxidized layer on the anode has a high resistance to corrosion, because of the compact film containing a higher content of oxygen formed on the anode. (C) 2003 The Electrochemical Society.