A batch tank of 1.6 L capacity has been designed for Ni electrowinning using a Pt catalysed H-2-diffusion anode and a stainless steel/Ni cathode, both of 100 cm(2) area. The anode has high stability for sulphate baths of pH 3.5 with 35 gL(-1) H3BO3 and Ni2+ concentrations from 10 g L-1 up to saturation. Linear correlations between the cell voltage and current intensity are found, as expected for ohmic control of the process. Good electrowinning conditions at room temperature are obtained for Ni2+ contents from 50 gL(-1), using an interelectrode gap of 2 cm and regulating the solution pH by NaOH addition for periods of 30 min. Current efficiencies greater than or equal to 93% are always found. The energy costs increase linearly with increasing current density from 10 to 50 mA cm(-2), with values much lower than those obtained using a conventional lead anode. This indicates that the Pt catalysed H-2-diffusion anode is preferable for Ni electrowinning. The crystals are composed of high-purity Ni and have a face-centred cubic structure. Surface analysis by SEM shows that the grain size gradually increases with increasing current density, with no significant influence of the Ni2+ concentration.