Salts That Convert CO2 Into Electricity | Home Energy Storage

No time to read?
Get a summary

Salts That Generate Electricity From CO2

On a planet grappling with rising carbon dioxide levels, researchers are urgently pursuing a method that not only cuts global emissions but also removes long-standing pollutants from the air. CO2 has earned the label of the planet’s top adversary, yet a provocative question remains: can it be reused, cleaned, and turned into a fuel that rivals gasoline or diesel?

Although the concept holds great promise, turning it into a practical reality is challenging. Many approaches tested so far struggle with carbon efficiency and the risk of producing fuels that are toxic, flammable, or hard to manage. A recent study led by researchers from the Massachusetts Institute of Technology and Harvard University in the United States suggests a breakthrough that could turn this ambitious idea into a viable technology.

Salts that produce electricity

In a study published in Cell Press Physical Sciences, this team describes a process that converts carbon dioxide directly into formate. These salts can exist as liquids or solids and, in turn, be used to generate electricity.

The process of transforming CO2 into formate salts is illustrated by a visual summary credited to Harvard University and MIT.

The formate family, including potassium formate and sodium formate, has many practical uses. They are commonly employed for de-icing roads and pavements. Importantly, they are not toxic or flammable, and they are easy to store and transport. They stay stable in standard steel containers and can be kept for months or even years after production.

Although the method has only been demonstrated at a laboratory scale, researchers believe it can be scaled. The goal is to provide heat and electricity for homes or industry with no emissions.

“In earlier efforts, the process was usually split into two phases,” notes Ju Li, an MIT engineer and leader of the study. “Other groups relied on chemically capturing gas, turning it into calcium carbonate, and then heating to release carbon dioxide while keeping carbon monoxide as fuel. The second step often yields low results, converting less than 20% of the captured carbon into the desired product.”

That team sought a smarter route and achieved conversion rates up to 90% of the captured carbon. The key change was to keep the product in a liquid state rather than heating it. In liquid form, electrochemical conversion to liquid formate salts is much easier than producing a gas. The highly concentrated liquid can be dried, for example by solar evaporation, to form a solid powder resembling crystals. This solid is remarkably stable and can be stored for years or even decades in ordinary steel tanks.

The accompanying images illustrate the emission-to-salt strategy, while researchers compare storage options for the new fuel forms.

Crystals store more efficiently than hydrogen in many setups. Hydrogen tanks can lose about 1% of gas per day, whereas formate salts offer a safer, stable alternative. Methanol, another candidate for storing recycled carbon, is toxic and poses health risks if leaks occur. By contrast, the formate salts proposed here present a safer, broadly useful storage solution that is less prone to hazardous leakage and widely deployed.

Beyond storing, the team also built a cell designed to use the new fuel and generate electricity. The formate particles, kept in water, are dissolved and pumped into a fuel cell when energy is needed.

A home refrigerator powered by CO2

Researchers say this conversion, storage, and battery system can adapt to a range of energy needs. In other words, the technology could be deployed for both domestic and industrial use.

In a household setting, one envisioned design involves a refrigerator-sized device that captures and converts carbon dioxide, storing the resulting material in an underground tank or on a roof. When energy is required, the crystalline powder is mixed with water and fed into a stack to deliver energy and heat.

Reference work: Cell Reports Physical Science, 2023, S2666-3864(23)00485-X. [Citation: Cell Reports Physical Science, 2023].

………………

Note: The environmental department is reachable at the listed contact channel for further inquiries and updates on this research area.

No time to read?
Get a summary
Previous Article

Everything changed in the 1960s: hybridization between domestic and wild cats over time

Next Article

Samsung confirms Android 14 support for newer Galaxy devices, excludes S20 and Note 20