Addition of electrochemically-active carbon to the negative active-material (NAM) has resulted in carbon-enhanced lead–acid batteries (CLABs). These batteries are performing well under partial state-of-charge (PSOC) conditions, whereas traditional batteries fail prematurely due to sulfation of the negative plate. At present, CLABs are the only mass-produced and viable technology available for start–stop and basic micro-hybrid vehicles and they are also expected to play a major role in grid energy-storage applications. The success of CLABs lies in the carbon which promotes both Faradaic and capacitive processes during high-rate PSoC operation. Understanding the differences between these processes is limited. Cyclic voltammetry (CV) has revealed the behaviour of different carbons with in terms of electrocatalytic activity towards Pb2+ reduction and capacitive contributions. Recently, it has been found possible to separate the Faradaic and the capacitive and contributions to the total charge for the lead–carbon electrode. The same study also showed that the presence of carbon at the lead interface substantially enhances the electrochemical activity and increases the Faradaic charge, whereas carbons with high surface-area augment the capacitive charge. The CV technique has been further employed to study combinations of carbons as physical mixtures and bilayers. Earlier efforts were confined to the study of carbons on planar lead electrodes. In the present work, investigations are extended to the carbons that are blended with PbSO4 powder. The resultant system, Pb–PbSO4 + C–H2SO4, has a close resemblance to the lead electrode in a CLAB.

Subhas Chalasani
East Penn Manufacturing Co.
R&D Consultant

Biography: Dr. Subhas Chalasani is an esteemed member of the Research and Development team at East Penn, the world's largest battery manufacturing company. As the company continues to explore new advancement in lead-acid batteries, like the UltraBattery®, and its integration with other battery technologies, Dr. Chalasani brings 30 years of R&D experience in both lead-acid and lithium-ion technology to the program. Dr. Chalasani has successfully led other prominent battery development programs at companies including Exide Industries Ltd., Boeing, General Motors, and AT&T Bell Labs. A Ph.D. in Electrochemistry along many patents and publications in battery and battery management designs support his well-respected career and highly valued work.

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