Lithum Sulfur batteries good for 1500 charges are good enough for electric cars

Lithium Sulfur Battery could find use in mobile applications, and eventually, electric vehicles with 300-mile range. Researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated in the laboratory a lithium-sulfur (Li/S) battery that has more than twice the specific energy of lithium-ion batteries, and that lasts for more than 1,500 cycles of charge-discharge with minimal decay of the battery’s capacity. This is longest cycle life reported so far for any lithium-sulfur battery.

Just last month Nextbigfuture reported an advance to 200 charge cycles for lithium sulfur. 1500 charge cycles provide batteries that last about 5-10 years or more. Depending upon the consumers usage of the car and the frequency of charging.



The initial estimated cell-level specific energy of the cell was 500 W·h/kg—much higher than that of current Li-ion cells (~200 W·h/kg). Even after 1,500 cycles, the cell exhibited a very high specific capacity (740 mA·h/g of sulfur), which corresponds to 414 mA·h/g of electrode—still higher than state-of-the-art Li-ion cells. These Li/S cells with lithium metal electrodes can be cycled with an excellent Coulombic efficiency of 96.3% after 1,500 cycles, which, the team said, was enabled by its new formulation of the ionic liquid-based electrolyte.

Lithium-sulfur batteries are attractive for electric vehicles and advanced electronic devices due to their much higher theoretical specific energy (∼2600 W·h/kg) than that of current lithium-ion cells (∼600 W·h/kg). This is due to the very high specific capacity of sulfur (1675 mA·h/g), based on a two-electron reaction (S + 2Li+ + 2e− Li2S)—significantly larger than the specific capacities of current cathode materials (130−200 mA·h/g).
