Low-Cost, Mercury-Free Electrical Switches and Relays

Mercury is a toxic, volatile metal that is used in electrical switches, relays, and motion detectors because of its electrical conductivity, low volatility, and fluid properties over a large temperature range. Mercury is released into the atmosphere during incineration of trash containing discarded electrical switches, relays, and motion detectors and rapidly migrates to the aquatic environment where it is ingested by fish, presenting a serious persistent hazard to humans and wildlife. Nearly all fish in the United States now contain traces of mercury in amounts that can cause permanent brain damage in children and adults who include fish in their diet. As a result of this hazard, the amount and type of fish recommended for human consumption has been restricted. Infoscitex proposes to develop a new class of mercury-free, electrical switches (MFES) and relays that function efficiently while utilizing environmentally safe, nonvolatile, electrically conductive, organic ionic liquids (IL) in place of mercury metal. The IL component will be designed to exhibit properties that make it ideal for use in an electrical switch; namely, it will remain a nonviscous liquid between -40°C and 350°C, is thermal-oxidatively and electrochemically stable, and exhibits resistance to fire. In Phase I, Infoscitex will apply computational analysis first, to identify the most promising IL candidates for synthesis, characterization, and testing as low-cost, nontoxic, electrically conductive liquids suitable for use in switches and relays. Selected IL candidates will be tested for nonvolatility, electrical conductivity, negative surface meniscus formation, and environmental safety. Feasibility will be demonstrated by constructing and testing a simple IL switching device. Infoscitex’s team includes experts in ionic liquids and computational analysis and a leading manufacturer of mercury electrical switches and relays. In Phase II, Infoscitex will refine the MFES, scale up to larger quantities, and produce prototype switches and relays. These will be evaluated for performance at Infoscitex and its electrical switch manufacturer teaming partner who will assist in commercializing the successful MFES product. The enhanced environmental protection, improved electrical performance, and competitive cost of Infoscitex’s proposed MFES product will encourage its immediate acceptance as a drop-in replacement for mercury-containing switches, relays, accelerometers, and motion detectors in commercial and military automobiles, aircraft, ships, and industrial electronic components. Substantial cost savings will be realized because of the elimination of expenses associated with worker safety and hazardous waste disposal. The long-term benefit to the environment cannot be overstated.