Harvesting Electrical Power during Carbon Capture using Various Amine Solvents.

There exists an urgent demand for the advancement of technologies that reduce and capture carbon dioxide (CO2) emissions to mitigate anthropogenic contributions to climate change. This paper compares the maximum power densities achieved from the combination of reverse electrodialysis (RED) with carbon capture (CC) using various CC solvents. Carbon capture reverse electrodialysis (CCRED) harvests energy from the salinity gradients generated from the reaction of CO2 with specific solvents, generally amines. To eliminate the requirement of freshwater as an external resource, we took advantage of a semiclosed system that would allow the inputs to be industrial emissions and heat and the outputs to be electrical power, clean emissions, and captured CO2. We assessed the power density that can be attained using CCRED with five commonly studied CC solvents: monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2-methyl-2-propanol (AMP), and ammonia. We achieved the highest power density, 0.94 W m-2 cell-1, using ammonia. This work provides a foundation for future iterations of CCRED that may help to incentivize adoption of CC technology.

Powering Electronic Devices from Salt Gradients in AA-Battery-Sized Stacks of Hydrogel-Infused Paper.

Strongly electric fish use gradients of ions within their bodies to generate stunning external electrical discharges; the most powerful of these organisms, the Atlantic torpedo ray, can produce pulses of over 1 kW from its electric organs. Despite extensive study of this phenomenon in nature, the development of artificial power generation schemes based on ion gradients for portable, wearable, or implantable human use has remained out of reach. Previously, an artificial electric organ inspired by the electric eel demonstrated that electricity generated from ion gradients within stacked hydrogels can exceed 100 V. The current of this power source, however, was too low to power standard electronics. Here, an artificial electric organ inspired by the unique morphologies of torpedo rays for maximal current output is introduced. This power source uses a hybrid material of hydrogel-infused paper to create, organize, and reconfigure stacks of thin, arbitrarily large gel films in series and in parallel. The resulting increase in electrical power by almost two orders of magnitude compared to the original eel-inspired design makes it possible to power electronic devices and establishes that biology's mechanism of generating significant electrical power can now be realized from benign and soft materials in a portable size.

The Green Lean Amine Machine: Harvesting Electric Power While Capturing Carbon Dioxide from Breath.

As wearable technologies redefine the way people exchange information, receive entertainment, and monitor health, the development of sustainable power sources that capture energy from the user's everyday activities garners increasing interest. Electric fishes, such as the electric eel and the torpedo ray, provide inspiration for such a power source with their ability to generate massive discharges of electricity solely from the metabolic processes within their bodies. Inspired by their example, the device presented in this work harnesses electric power from ion gradients established by capturing the carbon dioxide (CO2 ) from human breath. Upon localized exposure to CO2 , this novel adaptation of reverse electrodialysis chemically generates ion gradients from a single initial solution uniformly distributed throughout the device instead of requiring the active circulation of two different external solutions. A thorough analysis of the relationship between electrical output and the concentration of carbon capture agent (monoethanolamine, MEA), the amount of CO2 captured, and the device geometry informs device design. The prototype device presented here harvests enough energy from a breath-generated ion gradient to power small electronic devices, such as a light-emitting diode (LED).