217 Lead is a commonly available and highly corrosion-resistant metal that is often used as the negative electrode in lead-acid sec- ondary batteries where the formation of insoluble PbSO 4 during discharge terminates the cell operation. Despite the environmental problems associated with lead compounds, lead-acid batteries continue to be used in automobiles because of their large sales value, amounting to an estimated 30 billion US dollar each year. Lead corrosion by methanesulfonic acid in a secondary lead flow- battery with a soluble lead negative electrode and a lead (IV) diox- ide positive electrode in methanesulfonic acid solution has been reported and further exemplifies the importance of lead in energy storage devices [1, 2]. Oxygen reduction is an important process, particularly in metal-air batteries and fuel cells. Oxygen reduction takes place at the air cathode to complete the electrochemical reac- tion of the cell and generate electricity. Due to the slow kinetics of the oxygen reduction reaction, several compounds have been used as electro-catalysts. Highly dispersed platinum metal is an excel- lent electro-catalyst for oxygen reduction, but the cost of platinum hinders large-scale manufacturing. Various types of material has been used as air cathodes in metal-air batteries and fuel cells, but currently manganese dioxide compounds are the most widely used electro-catalysts in metal-air batteries and fuel cells, as they are readily available from manufacturers. In this work, lead corrosion and the surface formation of lead oxides at air cathode in a lead-air cell in methanesulphonic acid solution are investigated; this cell is an undivided primary metal-air cell using a lead negative electrode and a manganese dioxide air cathode. Lead foil (99.9%) was procured from Goodfellow Cambridge Limited, and methanesulfonic acid (99.9%) was procured from Sigma Aldrich. The air cathode was fabricated from catalytic man- ganese dioxide (MnO 2 ) powder mixed with small amounts of car- bon black powder to increase the conductivity. The catalytic pow- ders were pressed onto a nickel mesh current collector on both *To whom correspondence should be addressed: Email: wjbasirun@gmail.com Phone: 603 7967 4082, Fax: 603 7967 4193 Lead Corrosion and Formation of Lead Oxides from a Lead-air Cell in Methanesulfonic Acid Wan Jeffrey Basirun 1,2,* , Idris Mohamed Saeed 3 , Hanieh Ghadimi 2 , Magaji Ladan 2 Mohammad Reza Mahmoudian 4 , Mehdi Ebadi 5 , Lukman Bola Abdulrauf 2 , Zulkarnain Endut 6 1 Institute of Nanotechnology & Catalysis Research (NanoCat), Institute of Postgraduate Studies, University Malaya, 50603 Kuala Lumpur, Malaysia. 2 Department of Chemistry, University Malaya, Kuala Lumpur 50603, Malaysia. 3 Department of Chemical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia 4 Department of Chemistry, Shahid Sherafat, University of Farhangian, 15916, Tehran, Iran. 5 Department of Chemistry, Faculty of Sciences, Islamic Azad University, Gorgan, 49147-39975 Iran. 6 Center of Foundation Studies, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. Received: January 20, 2016, Accepted: October 15, 2016, Available online: November 29, 2016 Abstract: The corrosion of lead in methanesulfonic acid solution in the presence of a MnO 2 air cathode in a primary lead-air cell is in- vestigated. The highest power density of the lead-air cell is 2.8 mW cm -2 . X-ray photoelectron spectroscopy and powder X-ray diffraction results demonstrate the formation of lead (II) oxide and lead (IV) dioxide on the air cathode after continuous discharge. Field emission scanning electron microscopy image shows that the surface coverage of lead (II) oxide and lead (IV) dioxide on the air cathode is only partial and will allow oxygen reduction. Keywords: anodic dissolution; X-ray photoelectron spectroscopy; lead-air cell; lead oxides Journal of New Materials for Electrochemical Systems 19, 217-222 (2016) © J. New Mat. Electrochem. Systems