15 research outputs found
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Probing Mg Migration in Spinel Oxides
Mg batteries utilizing oxide cathodes can theoretically surpass the energy density of current Li-ion technologies. The absence of functional devices so far has been ascribed to impeded Mg2+ migration within oxides, which severely handicaps intercalation reactions at the cathode. Broadly, knowledge of divalent cation migration in solid frameworks is surprisingly deficient. Here, we present a combined experimental and theoretical study of Mg migration within three spinel oxides, which reveal critical features that influence it. Experimental activation energies for a Mg2+ hop to an adjacent vacancy, as low as ∼0.6 eV, are reported. These barriers are low enough to support functional electrodes based on the intercalation of Mg2+. Subsequent electrochemical experiments demonstrate that significant demagnesiation is indeed possible, but the challenges instead lie with the chemical stability of the oxidized states. Our findings enhance the understanding of cation transport in solid structures and renew the prospects of finding materials capable of high density of energy storage
Recommended from our members
Probing Mg Migration in Spinel Oxides
Mg batteries utilizing oxide cathodes can theoretically surpass the energy density of current Li-ion technologies. The absence of functional devices so far has been ascribed to impeded Mg2+ migration within oxides, which severely handicaps intercalation reactions at the cathode. Broadly, knowledge of divalent cation migration in solid frameworks is surprisingly deficient. Here, we present a combined experimental and theoretical study of Mg migration within three spinel oxides, which reveal critical features that influence it. Experimental activation energies for a Mg2+ hop to an adjacent vacancy, as low as ∼0.6 eV, are reported. These barriers are low enough to support functional electrodes based on the intercalation of Mg2+. Subsequent electrochemical experiments demonstrate that significant demagnesiation is indeed possible, but the challenges instead lie with the chemical stability of the oxidized states. Our findings enhance the understanding of cation transport in solid structures and renew the prospects of finding materials capable of high density of energy storage
Biochemical and molecular genetics of cystic fibrosis
Cystic fibrosis (CF) is the most common severe recessive genetic disorder in the Caucasian population. In 1938, D. H. Anderson provided the first comprehensive description of the disease and also introduced the name “cystic fibrosis of the pancreas.” Patients with CF suffer from excessive mucus accumulation resulting in severe clinical consequences in the respiratory, gastrointestinal, and genitourinary tracts (see Table I). All these symptoms are consistent with defects of exocrine glands, as suggested by S. Farber in 1945; he called the disease “mucoviscidosis,” a name still popular in some parts of continental Europe. CF patients also have elevated electrolyte levels in their sweat, an observation which, first described by di Sant’Agnese et al. (1953), became the hallmark for CF diagnosis.link_to_subscribed_fulltex