An ultra-high capacity lithium-sulfur battery developed by an international team of researchers is close to commercialization with the promise of powering a smartphone for five days at a Coulombic efficiency above Evenly distributed web-like bridging bonds hold fine particles together. The arrows in (C) illustrate the high degree of freedom for expansion and the easily accessible surfaces in the cathode. Source: M. Shaibani et al.Evenly distributed web-like bridging bonds hold fine particles together. The arrows in (C) illustrate the high degree of freedom for expansion and the easily accessible surfaces in the cathode. Source: M. Shaibani et al.99%.

Sulfur cathode failure, a common problem in this battery chemistry, is controlled by dispersing the conventional sodium carboxylmethyl cellulose binder to form a bridging architecture rather than a dense continuous network in the electrode. The new design links adjacent particles without covering them and supports fabrication of ultrathick cathodes with large reaction surfaces that can withstand cycling stresses and possess high ion accessibility and electrical conductivity. The bridging bonds between the carbon matrix and sulfur particles allow for extra space as the battery expands during charging.

High gravimetric and areal capacities were demonstrated for the expansion-tolerant electrodes with loadings up to 15 mg/cm2. The fabricated cells proved stable for more than 200 cycles, which is unprecedented in such thick cathodes.

Researchers from Monash University (Australia), University of Liège (Belgium), Fraunhofer Institute for Material and Beam Technology (Germany) and TU Dresden (Germany) have filed a patent on the sulfur cathode manufacturing process, which is described in Science Advances.

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