Researchers have successfully developed a new carbon-negative material using seawater, electricity, and carbon dioxide (CO2). This material, a mineral precipitate formed during a modified seawater splitting process, can store half its weight in trapped CO2 and can be used as a replacement for sand in the production of concrete or in certain plasters and paints. The research, published in the journal Advanced Sustainable Systems, focuses on altering the applied voltage, current, and CO2 injection rate during the precipitation process to tailor the properties of the minerals. The study found that mineral deposits of calcium carbonate and magnesium hydroxide form during the seawater splitting process, a common method in green hydrogen production. These deposits have traditionally been seen as an energy-intensive byproduct but are now viewed with potential for carbon sequestration. By controlling the synthesis of these minerals and engineering their deposition, the researchers can customize the properties of the precipitated minerals for various applications. The researchers inserted electrodes into a reactor filled with seawater, applied an electric current, and bubbled CO2 gas through the water to produce the carbon-sinking minerals. By controlling factors like voltage, current, CO2 injection, and seawater recirculation, they could vary the composition and properties of the minerals. These minerals can trap approximately half their weight in CO2, making them valuable for carbon sequestration. The material can also be used in construction materials like cements, plasters, and paints without compromising strength. This innovation could help reduce emissions in the construction industry, which is crucial for achieving climate targets. The scalability potential of the production method offers promise for large-scale deployment. The researchers are continuously working on enhancing the control of the mineralization process and industrializing the technology to make it more widespread.