Alex Bates

A Review of the Application of CNTs in PEM Fuel Cells

Fuel cells are an important source of renewable energy technology and currently the subject of much research. Hydrogen gas, which is the main fuel source in fuel cells, is relatively easily available, and the exhaust does not consist of greenhouse gases, unlike fossil fuel-based power sources. Some of the challenges persisting in fuel cell technology are the cost of the fuel cell due to factors such as platinum catalyst loading and water management. This study reviews the use of carbon nanotubes (CNTs) in fuel cell applications. CNTs have a large number of superior properties, including electrical conductivity, thermal conductivity, mechanical strength, and ability to support catalysts by providing an increased surface area. Carbon nanotubes offer great promise for overcoming the problems of existing fuel cells. However, they still pose challenges of functionalization on components of the polymer electrolyte membrane fuel cell (PEMFC), namely the membrane electrode assembly (MEA), the gas diffusion layer (GDL), and the bipolar plates. This paper discusses various experimental techniques that have achieved success in this functionalization process. Application of CNTs in fuel cells is expected to improve fuel cell performance and efficiency and bring down the cost by reducing platinum (Pt) catalyst loading

Novel mesoporous microspheres of Al and Ni doped LMO spinels and their performance as cathodes in secondary lithium ion batteries

ABSTRACT A facile, scalable, and solution-based technique is used to fabricate Al and Ni-doped (LiAl0.1Mn1.9O4 and LiAl0.1Ni0.1Mn1.8O4) microspheres of lithium manganese oxide (LMO) spinels for use as reversible cathode materials for lithium ion batteries (LIBs). The spheres of the two samples exhibit different porosities. Cells with these LMO-based cathodes are then cycled between 4.5 V and 2 V to study their stabilities while simultaneously being subjected to the undesirable Jahn-Teller distortion that occurs around the ~3 V regime. The LiAl0.1Mn1.9O4 (LAMO) and the LiAl0.1Ni0.1Mn1.8O4 (LANMO) cells exhibit comparable open circuit voltages (OCV) of 2.94 V and 2.97 V, respectively. During cell cycling, the LAMO cell exhibits a maximum specific capacity of 122.51 mAh g−1 with a capacity fade of 65.35% after 75 cycles. The LiAl0.1Ni0.1Mn1.8O4 (LAMO) sample fares better and exhibits a maximum of 140.49 mAh g−1 and a capacity drop of 52.59%. Detailed structural studies indicate that Ni doping and the greater degree of porosity of the LANMO sample to be a stabilizing factor. This is further confirmed by cyclic voltammetry (CV) and AC impedance spectra analysis.

Design and development of a fuel cell stack for hybrid power systems in small robot application

Proton Exchange Membrane Fuel Cells (PEMFC) are the most appropriate energy source for small robot applications. PEMFC is superior in power density and thermodynamic efficiency as compared with the Direct Methanol Fuel Cell (DMFC). Furthermore, PEMFC is lighter weight and smaller in size than DMFC, which are very important factors for small robot power systems. Operating conditions and fabricating methods are of key importance to fuel cell performance and efficiency. In this study, analysis of pressure drop, concentration variation, deformation of GDL and electrolyte, and stack clamping pressure were completed for a 500 watt PEM fuel cell stack. Several novel designs were discussed and will be continuously studied.