| Posted: Jun 29, 2016 | |
Charging ahead with nanowire magnesium batteries(Nanowerk News) A battery for laptops and smart phones that is long-lasting, safe and affordable is a step closer thanks to work by A*STAR researchers (Chemistry of Materials, "First-principles study of molybdenum chalcogenide halide nanowires for Mg-ion battery cathode application"). |
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| Portable electronic devices need smaller batteries with high energy capacities. Now, Man-Fai Ng and colleague Pei Shan Emmeline Yeo, from the A*STAR Institute of High Performance Computing, have investigated a possible cathode material for a magnesium-ion battery to overcome some problems of the common power source, lithium-ion (Li-ion) batteries. | |
| Constraints of Li-ion batteries include low power and limited battery life, which can be significantly improved if lithium is used as the negative electrode or ‘anode’. | |
| However, this creates safety issues as during charging and discharging of the battery, microscopic lithium fibers — known as dendrites — can form on the metal anode’s surface. | |
| If these dendrites reached the cathode, or positive electrode, the battery can short-circuit and catch fire. “Commercial Li-ion batteries use graphite as the anode to prevent this problem,” says Ng. “But the trade-off is that graphite is of lower energy density.” | |
| Magnesium metal, on the other hand, does not form dendrites and, in addition to having a higher volumetric energy density than lithium metal, is much more abundant — reducing the cost of raw materials. | |
| Magnesium-ion (Mg-ion) batteries therefore hold promise as next-generation batteries because they would be low cost, safe and have high energy density, explains Ng. One particularly challenge associated with Mg-ion batteries, however, is finding suitable cathode materials. | |
| “Typical Li-ion cathode materials are not compatible with Mg-ion due to its sluggish kinetics of insertion/desertion of magnesium ions in the cathode materials. Therefore, the performance of the Mg-ion batteries is low and of no practical use.” | |
| Ng and Yeo used supercomputer modeling to scan for a potential cathode material and identified one-dimensional molybdenum chalcogenide halide nanowires as a promising candidate. | |
| “Among the nanowires studied, the molybdenum selenide nanowire with molecular formula (Mo6Se6) exhibits the best battery performance for its fast ion insertion kinetics and moderately good charge capacity,” Ng says. | |
| The team plans to collaborate with experimental groups to verify this theoretical prediction, and continue searching for potential cathode materials for Mg-ion battery using first-principles modeling techniques. | |
| Ng says first-principles modeling is a powerful tool for battery research as it can accurately study the structural and electronic properties of electrode and electrolyte materials; and the interactions between different materials. | |
| More importantly, he says, it can be used for fast screening of materials with desired properties to speed up the search for useful materials to make Mg-ion batteries a reality sooner. |
| Source: A*STAR | |
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