Anode supported solid oxide fuel cells (SOFCs) with varying Ni content in the anode function layer (AFL) were fabricated and investigated. The observed open circuit potential (OCP) was higher with lower Ni content. However, the highest maximum power densities (MPDs) in the low temperature range, from 450 to 650 degrees C, were achieved at 60 wt% NiO in the AFL, which is a 1: 1 volume ratio of Ni (49 vol%) to Gd-doped ceria (GDC) (51 vol%) phase after reduction. The long term stability of the SOFC of this composition was demonstrated with a power density of similar to 1.1 W/cm(2) at 650 degrees C for 200 hours. Electrochemical impedance was consistent with these results showing the lowest electrode area specific resistance (ASR) at 49 vol% Ni, which has a linear relationship with MPD. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.009207jes] All rights reserved.