Magnesium (Mg) is one of the most readily available battery materials. Using brine as the electrolyte with carbon-based cathodes, Mg-air primary batteries can be constructed at a low cost. Researchers at the University of Tsukuba employed nanoporous graphene electrodes and a solid electrolyte to obtain a battery with performance equivalent or even superior to those of platinum electrode-based batteries.

Tsukuba, Japan—In pursuit of a carbon-neutral society, advancement of the battery technology becomes imperative. Primary batteries, though nonrechargeable, hold promise as power sources for sensors and disaster scenarios because of their cost-effective production and voltage stability. However, most of these batteries employ expensive metal electrodes, such as lithium electrodes, necessitating exploration of alternative electrode materials.

Using carbon-based materials for the cathode, magnesium (Mg) for the anode, oxygen from the atmosphere as the cathode active material, and brine for the electrolyte, Mg-air primary batteries can be constructed using inexpensive and abundant materials. Theoretically, these batteries are expected to match lithium-air batteries with regard to performance. However, they do not perform well in terms of battery capacity and operational stability.

Herein, we assembled a Mg-air primary battery using the prepared nitrogen-doped nanoporous graphene as the air cathodes and commercially available Mg sheets as the anodes, with a brine solution-soaked sodium polyacrylate gel constituting the solid electrolyte. Performance tests demonstrated that this battery exhibits comparable or superior performance to platinum cathode-based batteries. This is attributed to the porous electrode structure facilitating air transport as well as the ability of the solid electrolyte to prevent rapid corrosion of the Mg electrode.

This achievement is expected to broaden the applications of primary air batteries and promote the utilization of primary air batteries comprising materials more cost-effective and readily available than platinum and lithium.

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This work was sponsored by JSPS KAKENHI (Grant Numbers JP20H04628, JP21H02037 and JP23K17661), Science Fund Program for Distinguished Young Scholars of the National Natural Science Foundation of China (Overseas), and Shenzhen Science and Technology Program (Grant No. JCYJ20220531095404009, RCBS20221008093057027), Guangdong Basic and Applied Basic Research Foundation (2022A1515110676), a cooperative program (Proposal No. 202211-CRKEQ-0002) of CRDAM-IMR, Tohoku University, NIMS micro-structural characterization platform as a program of "Nanotechnology Platform Project," MEXT, Japan, Grant number JPMXP09A19NM0033. H.-J. Qiu thanks Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive Applications (No. ZDSYS20220527171407017).

Original Paper

Title of original paper:

All-Solid-State Mg-Air Battery Enhanced with Free-Standing N-Doped 3D Nanoporous Graphene

Journal:

Small

DOI:

10.1002/smll.202308045

Correspondence

Associate Professor ITO Yoshikazu
Institute of Pure and Applied Science, University of Tsukuba

Related Link

Institute of Pure and Applied Sciences