Lithium-ion batteries can be said to be one of the most common batteries today but new technologies will always appear and potential next-generation batteries include sodium-ion batteries, zinc-ion batteries, and now "magnesium-ion batteries."

The University of Cordoba in Spain, Xiamen University in China, and the Bulgarian Academy of Sciences have joined forces to use new compounds to open up new avenues for electrochemical energy storage systems, in which lithium-ion batteries are the battery leader, but carry some inherent problems including battery materials concentrated in Latin America, the scarcity of cobalt and lithium metals, and the safety issues of the battery itself.

In the past, many research groups have been looking for new battery replacement materials, including sodium, calcium, aluminum, and magnesium, and now the joint team of the University of Córdoba is deeply exploring the feasibility of magnesium-ion batteries. Like lithium ion batteries, magnesium ion batteries are composed of anode, cathode, and electrolyte. They have the advantages of low cost, no crystal dendrites, abundant magnesium reserves, non-toxicity, and high energy storage performance.

However, due to the high activity of magnesium, not all materials can “cooperate” with magnesium and the team studied the relatively stable oxide Mg2MnO4 which uses the redox process to generate electricity with the final battery voltage reaching 3.1 V, which means the energy density of the battery in the laboratory is 335 Wh/kg or about 60% of a lithium-ion battery.

In the past, the voltage of magnesium-ion batteries was at most 2.2 V and battery capacity was quickly cut in half during the charging and discharging process, said Gregorio Ortiz, a researcher at the University of Cordoba. However, as an optimization strategy was introduced, the rate of capacity decline was slow down. At present, the team has confirmed the feasibility of the battery but at this stage there is only laboratory testing and the performance of the battery after mass production has to be observed and this still requires a large amount of capital to have an opportunity to achieve.

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