Intercalation and exfoliation are effective approaches for enlarging the interlayer distance and increasing ion exchange capacity of layered materials. Here, an in-situ intercalation method is demonstrated to expand the inter-layer spacing of electrodeposited NiFe Layered Double Hydroxides (LDH) electrodes. Compared with traditional electrode fabrication method, in which intercalation/exfoliation of LDH powders is performed first followed by coating it on substrate, better interface connection and stability are maintained in the present method. It is found that the inter-layer distance of NiFe LDH material can be increased from 7.8 to 9.5 angstrom by immersing the electrode in formamide at 80 C-circle for 3 h, and the required overpotential of oxygen evolution reaction (OER) for sustaining 10 mA cm(-2) current density is reduced from 256 to 210 mV. Moreover, with the assistance of ultrasound treatment, the required intercalation time is reduced drastically and the overpotential@10 mA cm(-2) current density is further decreased to 203 mV. (C) 2017 Elsevier B.V. All rights reserved.