Electrodeposition Based Synthesis of Metal-Air Battery Cathodes

Metal air batteries offer the opportunity for unprecedented energy density improvements relative to existing battery technologies. Air cathodes are usually comprised of a catalyst, conductive additives, binder, and current collector. The current collector provides support and conductivity, the binder provides physical adhesion, and the catalyst facilitates the oxygen reduction process at the cathode. Thus, each component plays an important role in the function of the overall electrode. Additionally, access of the catalyst particle to oxygen is critical, so the cathode porosity must be appropriately tuned. Electrodes are often fabricated using physical mixing methods, where issues can include poor interparticle contact and limited access of the interior catalyst particles to oxygen. An electrodeposition based strategy for fabrication of a composite air cathode will be discussed. The first layer consists of a current collector substrate, which can be two dimensional (planar) or three dimensional in design. The second layer consists of a conformal conductive polymer coating. The third layer consists of catalyst particles. The second and third layers are each prepared using stepwise deposition processes. Advantages of the electrodeposition fabrication method will be described. Three-dimensionally structured composites can be easily generated via use of three dimensional substrates. All of the catalyst nanoparticles are positioned on the outer surface of the composite electrode, allowing facile access of oxygen gas molecules to the catalyst particle surfaces. Finally, the conductive polymer provides added conductivity and improved stability to the composite. Resulting impact on conductivity and oxygen reduction activity of the composite electrode will be discussed. References 1. S.H. Lee; S. Zhu; C.C. Milleville; C.-Y. Lee; P. Chen; K.J. Takeuchi; E.S. Takeuchi; A.C. Marschilok. Electrochem. Solid-State Lett. 2010, 13(11), A162-A164. 2. A.C. Marschilok; S. Zhu; C.C. Milleville; S.H. Lee; E.S. Takeuchi; K.J. Takeuchi. J. Electrochem. Soc. 2011, 158(3), A223-A226. 3. A.C Marschilok; S.H. Lee; C.C Milleville; P. Chen; E.S Takeuchi; K.J Takeuchi. J. Composite Materials. 2012, 47(1), 33–40.