The growing demand for lithium-ion batteries in electric vehicle and energy storage applications raises concerns over a stable supply chain for lithium and cobalt. Researchers in South Korea are engineering next-generation secondary batteries as alternatives with a focus on magnesium (Mg), which is abundant in the Earth's crust.

Secondary batteries based on Mg are projected to deliver high energy density due to reliance a divalent ion instead of monovalent alkali metal ions such as lithium. However, commercialization has been hampered by difficulties encountered in efficiently charging and discharging Mg metal due to its reactivity withA new activation strategy enables efficient cycling of the metal using commercially available electrolytes. Source: American Chemical Society acsnano.2c08672 electrolytes, has hindered its commercialization.

A resolution to this obstacle has been developed to enable use of high-voltage electrodes and minimize corrosion of battery components. An artificial protective layer with a novel composition based on magnesium alkyl halide oligomers on the magnesium surface has been synthesized by dipping the Mg anode material into a reactive alkyl halide solution prior to cell assembly. The process described in ACS Nano facilitated the formation of nanostructures on the Mg surface, which in turn enhanced the dissolution and deposition of the metal, suppressed undesirable reactions with electrolytes and maximized the reaction area to induce highly efficient Mg cycling.

The technology developed by researchers from the Korea Institute of Science and Technology and Korea University can reduce the overpotential from more than 2 V to less than 0.2 V when charging and discharging Mg metal in a common electrolyte without corrosive additives. The Coulombic efficiency can be increased from less than 10% to more than 99.5% in a system that demonstrated stable charging and discharging of activated Mg metal more than 990 cycles.

This advance confirms that Mg rechargeable batteries can operate in conventional electrolytes that can be mass-produced.