Nanomaterial design and fabrication for energy storage

The ‘Internet of Things’ scenario envisions billions of wireless sensors acting as the environmental interface to provide data that will, amongst other benefits reduce analysis costs, improve safety and predict future trends. Non-rechargeable batteries are the predominant energy source for today’s commercial wireless sensors and both the energy and power demands dramatically reduce the lifetime of the primary batteries. The value of the useful data gathered is offset by the frequent battery replacement necessitated by their short lifetimes. The ultimate challenge facing the mass distribution of wireless sensors is meeting the energy and power requirements to match the lifetime of the microdevices. Hybrid systems comprising a significantly smaller and rechargeable energy storage elements coupled to energy harvesters are of interest to enable wireless operation over the lifetime of the device. Li-ion rechargeable batteries provides the highest energy density (~270 Wh/kg) but the limitations of a typical organic solvent–based Li-ion batteries include a modest cycle life (<1,000) and low power density (