OBITUARY: KATHRYN BULLOCK, 1945-2021 Kathryn Bullock one of the greats in the electrochemical history of the lead battery has passed away aged 76.
Mapping out the landscape for future generations of lead research It is with sadness we record that Kathryn Bullock, one of the giants of the electrochemistry of lead and batteries in general, passed away on May 17. She was widely admired for not just her encyclopaedic knowledge of VRLA batteries but as a sunny, friendly and an engaging person. She was a regular speaker on behalf of the research side of the battery industry. Lead veteran Gene Valeriote recalls: “Kathy was ebullient, generous and an electrochemical genius. She was simultaneously a friend as well as a colleague. I first met her when she was a secretary/ technician at Gates— the pioneer of the VRLA battery — where she got so absorbed into what was going on, she left and returned with a doctorate!” David Rand, also a Gaston Planté award winner, recalls how they both came out of the gala dinner of the Electrochemical Society in New Orleans singing songs from Oklahoma and dancing down a crowded pathway. Her many achievements include becoming the first ever female president of the Electrochemical Society in 1996 and also winner that year of the lead battery industry’s highest accolade, the Gaston Planté Medal Award. The award recognized Bullock’s contribution to the lead battery world for
Kathryn working in the Johnson Controls research laboratory studying cyclic voltammograms of lead in battery acid containing phosphoric acid
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her discoveries of: • the self-discharge processes in VRLA batteries and their impact on shelf life and discharge capacity; • the structure and properties of the corrosion layer on Pb, Pb-Sr and PbSb electrodes; • how the corrosion layer of the positive plate on a solid-state Pb/PbO/ PbO2 element with an emf (electromotive force) of 0.8V can be formed and its effect on the polarization of the positive plate; • the beneficial influence of H3PO4 on the positive plate of lead acid batteries; • the influence of antimony on the negative plate; • how tridimensional E-pH-pS diagrams of Pb/H2SO4/ H2O could show thermodynamic values for open-circuit voltages, acid activities and lead sulfate solubilities; • the recombination efficiency of the oxygen cycle in VRLA batteries; • new conductive materials and processes to enhance lead battery formation; • the possibility of perovskite coating of the lead current collectors in positive plates to reduce corrosion. She was the author and co-author of more than 60 scientific papers, chapters and books and has 11 US patents in battery, fuel cell and capacitor technology. Norma) Kathryn Rice was born in Bartlesville, Oklahoma on September 24. 1945. An early interest in chemistry developed into a degree at Colorado University and in 1967 (freshly married to Kenneth Bullock who later became a minister), she applied to Gates Rubber Company where she was interviewed by John Devitt, the driving force behind the VRLA battery, who was organizing a battery development group. She left to move to Chicago to get her doctorate before returning to Devitt whose team had by then developed the VRLA battery. The push was on to test and refine the design and develop the manufacturing processes. The first application
of the Gates VRLA AGM battery was in power tools. Lead-acid batteries with silica gel added to the acid could be used in some portable applications, but the gel limited the power. Portable power tool companies were interested in the VRLA cells because of lower materials costs and higher voltages and power. Although lead is heavier than nickel and cadmium, they could use three lead-acid cells to replace the voltage of a battery of four nickel-cadmium cells. When lead-acid batteries are discharged, the state of charge decreases as the acid concentration decreases. Many stationary lead-acid battery applications, such as standby backup power, required regular monitoring of the acid specific gravity with a hydrometer to determine the energy left in the battery. A sealed cell was not acceptable for these critical applications. With her background in computer modelling and physical chemistry, Bullock was able to develop a model and numerical tables that would allow customers to convert the open circuit voltage of a VRLA battery to the acid concentration and battery state of charge. She was also able to use thermodynamic data from the literature to correct the state of charge for the internal battery temperature. She later recalled: “To maintain my skills and increase my knowledge of lead acid batteries, I began reading articles in the Journal of Electrochemical Society on corrosion reactions at the lead-acid positive grid by Paul Ruetschi, Jeanne Burbank, Detchko Pavlov, and others. With electrochemists from local universities, I also founded a local chapter of the Electrochemical Society.” In an evening graduate course on corrosion at the Colorado School of Mines, she learned about potential pH (Pourbaix) diagrams. Since positive grid corrosion reactions are dependent on both sulfate (S) and hydrogen (H) ion concentrations at the corrosion interface, she developed a threedimensional potential/pH/pS diagram that could be used to better understand and reduce the corrosion of the positive
Batteries International • Summer 2021 • 17
