USC scientists may have just identified a solution for one of the biggest stumbling blocks to the next wave of rechargeable batteries – small enough for mobile phones and robust enough for cars.
Derek Moy and Sri Narayan of the USC Loker Hydrocarbon Research Institute outline how they introduced an alteration to the lithium-sulphur battery that could make it more than competitive with the industry standard lithium-ion battery.
The lithium-sulphur battery, long considered being better at energy storage capacity than its more common lithium-ion counterpart, was hampered by its short cycle life. Currently the lithium – sulphur battery can be recharged 50 to 100 times – impractical as an alternative energy source compared to 1,000 times for numerous rechargeable batteries on the market today.
The solution devised by Narayan and lead author and research assistant Moy is something they call the ‘Mixed Conduction Membrane,” or MCM, a small piece of non-porous, fabricated substance sandwiched between two layers of porous separators, soaked in electrolytes and placed between the two electrodes.
The membrane works as a constraint in diminishing the shuttling of dissolved polysulphides between cathode and anode, a procedure that enhances the fort of cycle strain that has made the use of lithium-sulphur batteries for energy storage a challenge. The MCM still enables for the necessary movement of lithium ions, copying the process as it occurs in lithium-ion batteries.
Such novel membrane solution preserves the high-discharge rate potential and energy density without losing capacity over time. At numerous rates of discharge, the scientists identified that the lithium-sulphur batteries that are made to use of MCM led to 100 percent capacity retention and had up to 4 times longer life compared to batteries without the membrane.
“This advance eradicates one of the major technical constraints to the commercialization of the lithium-sulphur battery, enabling us to realize better options for energy efficacy,” says Narayan, senior author and lecturer of chemistry at the USC Dornsife College of Letters, Sciences and Arts. “We can now emphasize our efforts on enhancing other parts of lithium-sulphur battery discharge and recharge that hurt the entire life cycle of the battery.”
Lithium-sulphur batteries have a range of benefits over lithium-ion batteries. They are prepared with abundant and cheap sulphur, and are two to three times denser, which makes them both smaller and better at storing charge.
A lithium-sulphur battery would be perfect for saving space in mobile phones and computers, as well as enabling for weight reduction in future electronic automobiles, including planes, cars and further diminishing reliance on fossil fuels, says the scientists. The actual MCM layer that Moy and Narayan devised is a sleek layer of lithiated cobalt oxide, though future alternative substances could produce even better results. According to them, any replacing substance employed as an MCM must satisfy some basic criteria
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