A Story of Disordered Arrangements

If a disordered arrangement is created in high-entropy ceramics (HECs), an unprecedented performance can be achieved lithium-ion batteries. This significant improvement due to the suppression of short-range ordering, considered chief culprit chain down Li-diffusion. unfolding story about October issue Nature Materials by Ceder’s group. What so exciting HECs? Have we ever imagined what was key discovering these materials, and there any existing analogous material? Well, new class HECs are evolved from metallurgical high entropy alloys (HEAs).1Cantor B. Chang I. Knight P. Vincent A. Microstructural development equiatomic multicomponent alloys.Mater. Sci. Eng. 2004; 375: 213-218Crossref Scopus (3191) Google Scholar These materials significant, as they allow participation multiple elements (≥5) preferably proportion or with slight deviation for example (V0.2Nb0.2Ta0.2Mo0.2W0.2)C NaNi0.12Cu0.12Mg0.12Fe0.15Co0.15Mn0.1Ti0.1Sn0.1Sb0.04O2.2Zhao C. Ding F. Lu Y. Chen L. Hu Y.S. High-Entropy Layered Oxide Cathodes Sodium-Ion Batteries.Angew. Chem. Int. Ed. 2020; 59: 264-269Crossref (87) Recently, were seen excel metallurgy,3George E.P. Raabe D. Ritchie R.O. High-entropy alloys.Nat. Rev. Mater. 2019; 4: 515-534Crossref (678) superionic conductivity,4Bérardan Franger S. Meena Dragoe N. Room temperature lithium conductivity oxides.J. A Energy Sustain. 2016; 9536-9541Crossref electrocatalysts, thermoelectricity, energy storage devices.2Zhao Their excellence evolves their randomness or, technically, simultaneous solubility offers tool tailor desired properties. uniform distribution various transition metals (TMs) allows them effectively suppress cation ordering (SRO), which detrimental With marriage most recently developed rocksalt (DRX) cathodes5Lee J. Urban Li X. Su Hautier G. Ceder Unlocking potential cation-disordered oxides rechargeable batteries.Science. 2014; 343: 519-522Crossref PubMed (644) play wonders devices. In coming years, society poised benefit experience thrill directly tied few newly HECs, but arrangements today has consumed days making. The findings group6Lun Z. Ouyang Kwon D.-H. Ha Foley E.E. Huang T.-Y. Cai Kim H. Balasubramanian M. Sun et al.Cation-disordered rocksalt-type cathodes Li-ion batteries.Nat. https://doi.org/10.1038/s41563-020-00816-0Crossref (43) could not well appreciated without knowing previous voluminous efforts synthesize cathodes,5Lee all went jolt age-old belief ordered cations only option enhance authors completely aware that way density would pass through chopping systematic layered cathodes, that, synthesized first member DRX family (Li1.211Mo0.467Cr0.3O2), utilizes 0-TM percolation theory.5Lee also found out SRO usually restricts percolation, contrary random TM species. Furthermore, offer compositional flexibility allowing incorporations many TMs. Nonetheless, if idea HE works, it further broaden chemistry TMs, more periodic table added, pushing reliance on selected suppressing SRO, enhancing diffusions even further. To investigate applicability DRX, set three prototypes formulated, bringing 30% excess content (over stoichiometry) simultaneously 15% oxygen substitution ensure better transport evading TMs redox capacity ensuring reservoir, respectively (Figure 1A). configuration assisted sequentially increase formidable success inspires indeed opens up possibilities explore other configurations. finding act torchbearer compounds species less than four have been categorized low (LE) (HE) respectively, while indicating mixing (Figures 1B 1C). They predicted taking Li1.3 F0.3/f.u. conjunction 23 possibility, combination 7965 achieved. Obviously, when such huge number exists, always issues incompatibility. avoid this, hinted at this refraining combinations (gray color Figure 1D). probabilistic compatibility pairs normalized between 0 1 highly compatible compatible, respectively. Grass greener mixings. Most importantly, care must taken Mg2+, Zn2+, Ga3+, Al3+, Sn4+, expresses strong dislikes thus concentrations should kept minimum. creates possibility designing putting several species, shown 1E (12 TMs). Eventually, some show double triple centers. For instance, seems beneficial include Mn (Mn2+/Mn4+), Mo (Mo4+/Mo6+), V (V3+/V5+) category, electron capacity. situation often required high-energy-density cathodes. On contrary, Cr negates its wider (Cr3+/Cr6+) center capability form phases voltages, additionally imposing Cr3+. Excitingly, non-redox features d0 (Nb5+ Ti4+) possess display enthalpy mixing, used charge compensator active resulting Through studies, able demonstrate delivery increases TM2 (220.0 mAh g-1) TM4 (269.0 g-1), highest TM6 (307.0 g-1). Extensive structural characterization theoretical calculations revealed large choice particular responsible increasing Additionally, involvements anionic chemistries arising simultaneous/sequential compared convention Li-excess cathodes.7Seo Lee Malik R. Kang chemical origin activity cathode materials.Nat. 8: 692-697Crossref (611) Scholar,8Luo K. Roberts M.R. Hao Guerrini Pickup D.M. Liu Y.-S. Edström Guo Chadwick A.V. Duda L.C. Bruce P.G. Charge-compensation 3d-transition-metal-oxide intercalation generation localized holes oxygen.Nat. 684-691Crossref (569) research two aspects during synthesis HECs-DRX. First, centers among It desirable frustrate boost provided amount lie above ≥1.2/f.u. Second, Mn2+ V3+ favorable choices trace Cr3+ voltage applications showcase three-electron While Nb Ti reservoirs. above-unfolded unexplored path toward developing materials. Nevertheless, exploration successful application batteries open possibilities. outcome study effort how challenging yet rewarding integrate different ideas eyeing futuristic modern electrifications. Having successfully obtained imbibed DRXs, shattered traditional state demonstrated controlled entropic fetch surprisingly compositionally flexible, incorporated, dressed-up multifunctional ranging thermoelectrics, conductors, efficient catalysts. author declares no competing interests.