Research team demonstrates Li-air battery capable of long cycle life

A team from Hanyang University (Korea) and University of Rome Sapienza (Italy) have demonstrated a lithium–air battery capable of operating over many cycles with capacity and rate values as high as 5,000 mAh g_carbon⁻¹ and 3 A g_carbon⁻¹, respectively. The team, led by Yang-Kook Sun and Bruno Scrosati, reports on their work in a paper in the journal Nature Chemistry.
Despite the extreme promise of lithium-air batteries—with estimates of energy densities some 10x those of current Li-ion batteries—the performance of Li-air batteries has been limited to only a few charge-discharge cycles, with low rate capability, the team notes.
Researchers suspects these issues may be connected to lithium oxidation products and intermediates, including Li₂O₂ and an anionic oxygen radical, O2·^–, a reactive species which decomposes typical electrolytes such as organic carbonate solutions of lithium compounds.
The team selected tetra(ethylene glycol) dimethyl ether-trifluoromethanesulfonate (TEGDME-LiCF₃SO₃, or TEGDME-lithium triflate) for use as a stable electrolyte, and reported that preliminary data showed evidence of reversible formation of Li₂O₂, fast kinetics and almost no degradation of performance for more than 100 cycles. The researchers suggested that the enhanced stability may be due to a fleeting oxygen radical lifetime in their electrolyte.



Source: Green Car Congress