High Power Battery and Fuel Cell Electrodes Enhanced with Nano Catalysts
By Kimberly McGrath, PhD, MBA
June 27, 2009
Next-generation electronic devices demand increased power and capacity that exceed the typical incremental improvements being offered by today’s Li-ion battery technology. But the use of nanocatalysts in the manufacturing of batteries and small fuel cells promises to change all of that. Researchers hope to demonstrate leapfrog increases in energy storage in the coming years.
By using formulations integrating high surface area metal nanocatalysts, signs of dramatic improvements in the performance of electrodes are emerging for primary batteries, rechargeable batteries, and fuel cells.
Ideally, batteries should be small, light weight, and capable of storing a large amount of energy at low cost. Metal-air power sources such as Zinc-air, Magnesium-air, and Aluminum-air batteries have some of the highest theoretical energy densities and are currently being used in both commercial and military applications. However, further improvements must be made in both power and longevity.
One way of improving performance is the use of higher surface area nanoscale catalysts and proper distribution in the air breathing gas diffusion electrode (GDE). For example, the improved kinetic performance of manganese nanocatalyst, combined with other improvements made in a typical battery structure, results in a significant increase in power density compared to commercial electrodes.
Unlike a battery, fuel cells such as the direct methanol fuel cell (DMFC) offer instant ability to recharge by direct fuel injection using cartridges, and longer operation time by virtue of increased energy density of the fuel. Currently, the largest barrier for fuel cells to reach commercialization is their cost relative to batteries. The largest contributing cost to a DMFC is the significant amount of platinum catalyst necessary for high power. Platinum loading needs to be minimized, and most ideally replaced with a less costly material while maintaining or increasing power. Furthermore, the DMFC should operate with reasonable power at high methanol concentration to decrease system size.
Through the integration of alternative high surface area, methanol tolerant nanoscale cathode catalysts, it is possible to improve high fuel concentration DMFC performance while minimizing the usage of platinum. This will aid in the miniaturization and commercialization of DMFCs as a source of portable power, particularly in applications where weight and volume savings are critical.
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