The new battery uses a cobalt-poor, nickel-rich layered cathode (NCM88) and a commercially available dual anion ionic liquid electrolyte, which provides a higher energy density of 560-Wh/kg and increased stability. (Image credit: Karlsruhe Institute of Technology)
Lithium-ion batteries are part of our daily lives, and we use them to power our mobile devices and electric vehicles. In the past, lithium-metal batteries have had a tendency to become stable or even explode under some circumstances, making them unsafe for the commercial market. They also have some issues, including short circuiting and limited range with EVs. Scientists from the Karlsruhe Institute of Technology (KIT) have found a way to make them safer and increase their energy density with a new type of lithium-metal battery.
Typical lithium-metal batteries employ an LP30 organic electrolyte, which causes particles to crack on the cathode, and when the electrolyte reacts with those cracks, it damages the structure. The problem stems from the electrode materials reacting with conventional electrolyte systems, which causes a host of stability problems with increased energy densities. The scientists have mitigated those issues by designing a new lithium-metal battery that uses a cobalt-poor, nickel-rich layered (NCM88) cathode and a dual anion ionic liquid (ILE) electrolyte, which provides an energy density of 560-Wh/kg and increased stability over many charge/discharge cycles.
It’s that ILE electrolyte that prevents structural damage on the NCM88 cathode, allowing the battery to reach 560-watt hours per kilogram of material. The scientists tested the new battery and found that after 1000 cycles, it still reached 88% of its capacity. The battery’s Coulombic efficiency, the ratio between charge and discharge, also sat at an astonishing 99.94% during testing. Of course, the new lithium-metal battery needs more development before it can become available on the market, but it’s a significant step forward.
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