Electrochemical Energy Generation and Storage. Fuel Cells and Lithium-Ion Batteries

Abstract

We illustrate our current work for electrochemical energy generation and storage (i.e., fuel cells and lithium-ion batteries, respectively). In fuel cell research, we have been developing Pt-based ordered intermetallic compounds as electrocatalysts towards anodic reactions of liquid fuels such as methanol, ethanol, and formic acid for proton-exchange membrane fuel cells (PEMFCs). Development of the intermetallic compounds ranges from bulk materials to nanoparticles. In our work, we have employed a combinatorial method to achieve rapid screening of a large number of potential electrocatalysts. Multi-element sputtering was employed to generate films with different compositions including most of a phase diagram and the resulting libraries were screened using a fluorescence assay. For portable applications, we have also developed a planar microfluidic membraneless fuel cell (PMMFC) device, which eliminates the need for a polyelectrolyte membrane (PEM) and takes advantage of the laminar flow of fuel and oxidant streams. Particularly, in order to increase power density (cell voltages) of a PMMFC device, we have focused on the development of a dual electrolyte PMMFC in which alkaline and acid electrolyte solutions are employed for fuel and oxidant streams, respectively. In lithium-ion battery research, we have been designing new cost-effective organic materials with high energy densities as cathode electroactive materials, targeting large applications such as electrically powered automotives. In particular, we have focused on organosulfur-based polymers, involving the redox chemistry of thiolates (RS−), capable of higher energy density than conventional lithium metal oxides such as LiCoO2. By combining electrochemical techniques with computational methods and organic synthesis, we have tried to establish an efficient procedure to develop novel organic-based electroactive materials suitable for the demands of energy storage materials for rechargeable lithium-ion batteries