An interactive map for HE-DRX stability and disorder temperature
High-entropy (HE) ceramics, by analogy with high entropy metallic alloys, are an emerging class of compounds composed of a large number of species. These materials offer the benefit of compositional flexibility and can be used in a wide variety of applications, including thermoelectrics5, catalysts, superionic conductors and battery electrodes. Among lithium(Li)-ion cathodes, cation-disordered rocksalt (DRX)-type materials are an ideal platform within which to design HE compounds because of their demonstrated chemical flexibility. We show in a recent Natur Materials paper that the systematic incorporation of more different metal species reduces cation short-range order (SRO) and greatly increases energy density and rate capability. By comparing a group of DRX cathodes containing two, four or six TM species, we show that SRO systematically decreases and energy density and rate capability systematically increase as more metal cations are mixed together, even though the total metal content remains fixed. A DRX cathode with six transition metals achieves 950 Wh/kg at low rate, and retains more than 170 mAh/g when cycling at 2A/g. To facilitate further design in this high-entropy DRX space we also present a compatibility analysis of different transition metals on top of 7965 HE-DRX compounds, and successfully synthesize a phase-pure HE DRX containing twelve TM species, as a proof-of-concept.
Click here to play with the interactive version of stability map.
The full paper describing how to engineer the kinetic performance is published in Nature Materials as “Cation-disordered rocksalt-type high-entropy cathodes for Li-ion batteries”.