SBIR-STTR Award

This SBIR Phase I project will address the technological risks in bringing silicon-based nanostructured thermoelectric materials from a proven laboratory concept to a scalable prototype device. Thermoelectric materials offer great promise in development of self-powered equipment for military use. They are compact, lightweight, highly reliable and virtually maintenance free. Implementation to date has been precluded by the high cost per watt and the low design temperature of existing thermoelectric materials Alphabet Energy’s silicon nanowire thermoelectric materials use low-grade silicon as a raw material and a manufacturing process that utilizes standard semiconductor fabrication tools and facilities. This leads to a device cost in the order of 20¢/Watt, 50-100 times cheaper than existing thermoelectrics. Silicon nanowire thermoelectric materials have been tested at temperatures up to 600C without degradation or loss of performance. As such much greater temperature gradients are possible, leading to power densities with existing performance materials of up to 17 kW/m2. Alphabet Energy’s SiNW thermoelectrics can provide a 100W of electric generation for a cost of as little as $16 at 10% efficiency. Furthermore we have an established development pathways to higher efficiencies of 20% or more, leading to a cost of only $8.

Keywords:
Thermoelectric, Silicon, Nanowire, Low-Cost, Waste Heat Recovery

Alphabet Energy, Inc., is commercializing a breakthrough thermoelectric material from the Lawrence Berkeley National Laboratory for waste heat recovery. Waste heat recovery is a US$50 billion opportunity in the US per year for the generation of electricity from waste heat in power plants, factories, and automobiles. In addition, waste heat from cookstoves as per this US Army SBIR project can be used to charge batteries and power local devices. Thermoelectrics are materials that, in the solid state, produce electricity directly from a temperature gradient. To date, existing thermoelectrics--based almost entirely on bismuth telluride--have seen poor adoption due to their prohibitively high costs. Alphabet's technology is the first thermoelectric entirely based on silicon, enabling devices 50-100x cheaper than existing ones at similar performance (~10% efficiency, or ZT=1.5). Alphabet saw progress during its Phase I award in building a structure incorporating this novel silicon-based nano material into a thermoelectric device. Alphabet will use a Phase II award to deliver working prototype thermoelectric devices to the Army for testing, and to prepare our devices for manufacturing using only existing semiconductor processing technology.

Keywords:
Thermoelectrics, Waste Heat Recovery, Power Generation, Energy Scavenging, Cookstove Auxiliary Power, Energy Efficiency.