The effect of lignin, which is an important additive for the negative electrode in lead±acid batteries, is studied on lead electrodes in sulfuric acid by means of potentiostatic transient measurements and in situ electrochemical atomic force microscope (EC-AFM) observations. During oxidation of the electrodes, it is con®rmed that the current transition in electrolyte with 20 ppm lignin gives a broad, hill-like curve, while that in electrolyte without lignin is a sharp peak. | ELSEVIER Journal of Power Sources 107 2002 167-172 In situ EC-AFM study of effect of lignin on performance of negative electrodes in lead acid batteries I. Bana Y. Yamaguchi3 Y. Nakayama3 N. Hiraib S. Harab aYuasa Corporation 2-3-21 Kosobe-cho Takatsuki Osaka 569-1115 Japan Department of Materials Science and Processing Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan Received 1 August 2001 accepted 30 October 2001 Abstract The effect of lignin which is an important additive for the negative electrode in lead-acid batteries is studied on lead electrodes in sulfuric acid by means of potentiostatic transient measurements and in situ electrochemical atomic force microscope EC-AFM observations. During oxidation of the electrodes it is confirmed that the current transition in electrolyte with 20 ppm lignin gives a broad hill-like curve while that in electrolyte without lignin is a sharp peak. Nevertheless there is little difference in electrode capacity in each electrolyte throughout the whole oxidation. In electrolyte with lignin in situ EC-AFM examination reveals a uniform deposition of lead sulfate crystals after oxidation of the electrode. These results suggest that lignin adsorbs on the electrode surface and promotes uniform diffusion of lead ions near the surface during oxidation. 2002 Elsevier Science . All rights reserved. Keywords Electrochemical atomic force microscopy Expander In situ observation Lead-acid battery Lignin Negative electrodes 1. Introduction Lead-acid batteries are widely used in automotive and standby applications 1 . In order to conserve energy and alleviate environmental problems research is being undertaken in the development of novel lead-acid batteries for electric vehicles EVs electric hybrid vehicles HEVs load-leveling LL installations etc. 1-5 . Since these new applications demand a higher performance from the battery a detailed understanding of the electrode reaction is very important. This .
