Eight lignin products have been characterized with regard to chemical composition, physical properties and function as battery expanders. Altogether, 128 different parameters have been measured for each of the expanders. The Principal Component Analysis method has been used to analyze the correlations between these parameters. Several possible correlations between lignin properties and effectiveness in batteries were found. The type of lignin seems to be a very important factor and few correlations hold across different types of lignin. (C) 2000 Elsevier Science S.A. All rights reserved.