tailieunhanh - Synthesis and electrochemical preformances of tribasic and tetrabasic lead sulfates prepared by reactive grinding

Tribasic lead sulfate Ž3BS. and tetrabasic lead sulfate Ž4BS., used as precursors of the positive active material in the leadracid batteries, were prepared by a new method: reactive grinding. The effects of various experimental parameters Žstoichiometry, hygrometry of the starting compounds, duration of mechanical treatment. upon the nature and morphological features of the resulting phase were investigated. | ELSEVIER Journal of Power Sources 72 1998 126-131 Synthesis and electrochemical preformances of tribasic and tetrabasic lead sulfates prepared by reactive grinding S. Grugeon-Dewaele a S. Laruelle a F. Joliveau-Vallat a L. Torcheux b A. Delahaye-Vidal a a Laboratoire de Réactivité et de Chimie des Solides URA CNRS 1211 33 rue Saint Leu 80039 Amiens Cedex France b CEAC Exide Europe 5-7 allee des Pierres Mayettes 92636 Gennevilliers Cedex France Received 12 May 1997 revised 24 July 1997 Abstract Tribasic lead sulfate 3BS and tetrabasic lead sulfate 4BS used as precursors of the positive active material in the lead acid batteries were prepared by a new method reactive grinding. The effects of various experimental parameters stoichiometry hygrometry of the starting compounds duration of mechanical treatment upon the nature and morphological features of the resulting phase were investigated. Among them hygrometry turned out to be the most critical one. With water in excess only 3BS was produced while dry reagents led to 4BS. In both cases samples with a small particle size and high reactivity were obtained. In order to evaluate the influence of the morphology upon the electrochemical performances of such grinding produced samples the capacity was measured and compared with that of traditional 3BS and 4BS samples. 1998 Published by Elsevier Science . Keywords Lead sulfate Performances Reactive grinding 1. Introduction During the last thirty years mechanochemistry has become a topic in the established field of reactivity of solids. The application of a mechanical energy to powder compounds leads generally to phase transitions or chemical reactions. For instance by ball milling a pure solid phase the energy transfer may cause the transition from the crystalline to the amorphous state. For several solid phases of powder compounds ground together chemical reactions may be initiated inside the ball mill although they usually take place at very high temperature leading to .