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 gcarbon−1 and 3 A gcarbon−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.
Hun-Gi Jung, Jusef Hassoun, Jin-Bum Park, Yang-Kook Sun & Bruno Scrosati (2012) An improved high-performance lithium–air battery. Nature Chemistry doi: 10.1038/nchem.137610.1038/nchem.1376