chapter  5
18 Pages

NANOSTRUCTURED TiO MATERIALS

BATTERY TECHNOLOGY OVER THE WORLDThe world battery market is estimated at over $70 billion with a continuous growth at 4.8% annually through 2012 (www.freedoniagroup.com). Non-lead-acid secondary battery demand will surpass primary and lead-acid secondary batteries. The demand will be headed by Asian countries, Poland, Brazil, and Russia, while markets in the industrialized countries will grow slowly. China is estimated to record the largest growth, with a demand for primary

and secondary batteries expecting to annually rise 13% through 2010 to $16 billion.The major driving force for the wide commercialization of rechargeable batteries was the extended use of portable devices. Especially, cell phones must be able to operate continuously in standby mode. It involves significant low power consumption from a small battery. Considering that primary batteries only return around 20% of the energy needed for their manufacturing, rechargeable batteries are the lowest cost solution. Other driving forces for the extended use of rechargeable batteries in portable devices are their high sensitivity to minor power losses or fluctuations; the increased demand for wireless game products; lower prices of cell phones, PDAs, and cameras; and the progressive substitution of desktop computers by laptops and netbooks. In the near future, there will be many other application fields demanding very small power sources. Thus, nanobatteries can be very useful as small, highpower, active RFID (radio frequency identification) batteries. MEMS (micro-electro-mechanical systems) batteries will be useful not only in the medical and pharmaceutical industry as power suppliers in implantable medical devices (several microns in size) but also for automotive industry as parts for projectors, optical switching, printers, and various sensors. These batteries could also be suitable for Smartdust. Smartdust is a concept for wireless MEMS sensors that can detect anything from light and temperature to vibrations. Professor Christopher Pister from UC Berkeley suggested in 2001 creating a new type of micro sensor that could theoretically be as small as a grain of sand. Research into this idea is under way and DARPA (the Defense Advanced Research Projects Agency) is funding the work. If these sensors are developed successfully, they will require tiny, powerful batteries to operate and transmit their data. The nanobatteries developed by the group of Peled [5, 6] might be able to supply the necessary power while keeping the size of the sensor as small as possible.Several rechargeable electrochemical systems have demonstrated to be useful accomplishing the needs of electronic devices in last decades. Mainly, nickel-cadmium and nickel-metal hydride have successfully contributed to the implementation

of portable communication and consumer electronic devices. Nevertheless, notorious disadvantages such as element toxicity, memory effects affecting the charge/discharge behavior, and limited energy densities have influenced the progressive shifting to lithium batteries. Rechargeable lithium batteries are light and compact. Their high energy densities make them suitable for portable applications. Moreover, the possibilities in further developments of high-performance lithium batteries are not still limited. Their charge/discharge lifespan and rates can be improved by research in new materials and designs. This will allow the expansion of their use to new applications deserving great expectations. In fact, Li-ion batteries share 80% of the battery industry market. The global sales of Li-ion batteries were 2.5 billion units in 2006 and continue to grow. In 2008, 2.71 billion units of Li-ion batteries were sold across the world, with a sales value of $8.03 billion. Cellular phone market accounts for 60% of the total consumption. The sales are expected to reach 3 billion units in 2010 in the world, with power and polymer batteries to be the new sources of growth of the battery market. Figure 5.1 illustrates a market that is far from exhausting its growing potential.