Nano-sized Ca2.8Cu0.2Co4O9 powders were synthesized by the solution combustion process, using five different fuels, i.e., aspartic acid, alanine, glutamic acid, glycine, and urea. The combustion process lowered both the calcination and sintering temperatures. The sintered Ca2.8Cu0.2Co4O9 consisted of plate-like grains that were favorable for high energy conversion efficiency. In the comparative study of various different fuels, aspartic acid-processed Ca2.8Cu0.2Co4O9 showed an extremely high Seebeck coefficient, thus resulting in an enhanced power factor. The highest power factor value (8.05 x 10(-4) Wm(-1) K-2) was attained for the aspartic acid-processed sample at 800 degrees C. (C) 2011 Elsevier B.V. All rights reserved.