The NiO particles were reduced within 1.0 w.t. % Li2O/LiCl molten salt at 650 degrees C with controlled cathodic potential -2.05 V (vs Ni/NiO), at which the Li metal was generated in situ. It took less than two hours for 2.0 g of NiO particles to obtain 96.1% of reduction extent using 100% of theoretical charge, which gives 96.1% current efficiency. The unprecedented high current efficiency for NiO reduction is due to both the lithiothermic and electrolytic reduction, which also suggests the high efficiency of the customized electrochemical cell setup used for this study. (c) 2018 The Electrochemical Society.