High power portable electronic

Electrochemical double-layer capacitors, often called supercapacitors, can store energy via reversible interfacial electrosorption of ions, and are used to power portable electronic equipment, hybrid electronic vehicle, and other devices. Supercapacitors have fast-charging and discharging rates and the ability to sustain millions of cycles. They bridge the gap between the batteries that offer high energy densities but are slow and between conventional electrolytic capacitors that are fast but have low energy densities. 

In recent decades, direct alcohol fuel cells (DAFCs) have been extensively studied and considered as possible power sources for portable electronic devices and vehicles in the near future. The application of methanol is limited due to its high volatility and toxicity, although it is relatively easily oxidized to CO2 and protons. So other short chain organic chemicals especially ethanol, ethylene glycol, propanol, and dimethyl... 

One of the lessons learned in the 1990s was that the enormous need for high-performance portable power is not diminishing. Consumer electronics continues to be a vibrant, worldwide market force, leading to ever-increasing demands for portable power. The inability of lithium ion batteries to fully satisfy consumer electronics has been one of the principal motivations for the dramatic rise in fuelcell research and development. As the dimensions of devices continue to shrink, the question arises as to... 

In an acidic medium, a PEMFC fed with ethanol allows power densities up to 60 mW cm to be reached at high temperatures (80-120 °C), but this needs platinum-based catalysts, which may prevent wider applications for portable electronic devices. On the other hand, in an alkaline medium, the activity of non-noble catalysts for ethanol or ethylene glycol oxidation and oxygen reduction is sufficient to reach power densities of the order of 20 mW cm at room temperature. This opens up the hope of developing SAMFCs that are particularly efficient for large-scale portable applications. 

It should also be noted that the demand for primary lithium batteries remains strong, particularly in military applications where there is high demand for lightweight and disposable power supplies for portable electronic devices. In fact, the US General Accounting Office (GAO) has indicated that primary lithium batteries were one of seven items for which supply shortages reduced operational capability and increased risk to [US] troops [3]. 

Since its introduction in 1990, the secondary rechargeable lithium-ion battery (LIB) with high energy density and power capability has become an important power source for portable electronic devices, such as cellular phones, laptop computers, and portable media players. Recently, LIB research has also widened to include the hybrid electric vehicles (HEV). 

The rare earth based metal hydrides AB5 have proven to be best suited for use in the negative electrode in NiMH batteries. The market demand for the nickel-metal hydride battery is high because of the rapid demand for portable electronics goods such as video cameras, shavers, power tools, cellular phones, lap-top computers which use high performance batteries. 

The new generation of silicon technology imaging transducers combined with ongoing electronic miniaturization and the availability of extremely fast and powerful portable laptop computers will lead to the development of portable or even wearable high-resolution scanners affording wireless data transfer. This technology will help to make communication with remote locations and advanced medical applications more affordable. 

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