In-Situ Neutron Studies of Electrodes for Li-Ion Batteries Using a Deuterated Electrolyte: LiCoO2 as a Case Study

An electrochemical cell for in-situ neutron powder diffraction studies of electrode materials for lithium-ion batteries is presented. The device has a coin cell geometry, consisting of 8.4 cm diameter, circular components that can be stacked together and clamped tight using sixteen polyetheretherketone (PEEK) screws. The background issue associated with incoherent scattering from hydrogen within the organic electrolyte was addressed by replacing the normal electrolyte with a deuterated analogue, significantly improving the peak-to-background ratio of the in-situ neutron data. Initial in-situ studies showed clear structural evolution within LixCoO2 during charge in a half-cell with lithium metal as the counter electrode, in agreement with previous studies. In addition, the in-situ cell was shown to provide electrochemical performance comparable to that of equivalent coin cells of the commercial design and, following these demonstration studies, is available for in-situ structural studies of other lithium cathode and anode materials during charge/discharge cycling

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Pyrochlore to Fluorite Transition: The Y2(Ti1-xZrx)2O7 (0.0 ≤ x ≤ 1.0) System

The structural properties of the system Y-2(Ti1-xZrx)(2)O-7 have been investigated using the neutron powder diffraction technique, including a detailed analysis of the "total scattering" using reverse Monte Carlo modeling to probe the short-range ion-ion correlations over sample range 0.

Pyrochlore to Fluorite Transition: The Y2(Ti1-xZrx)2O7 (0.0 ≤ x ≤ 1.0) System

The structural properties of the system Y-2(Ti1-xZrx)(2)O-7 have been investigated using the neutron powder diffraction technique, including a detailed analysis of the "total scattering" using reverse Monte Carlo modeling to probe the short-range ion-ion correlations over sample range 0.

Proton conductivity of hexagonal and cubic BaTi1-xScxO3-δ (0.1 ≤ x ≤ 0.8)

BaTi1−xScxO3−δ (x = 0.1–0.8) was prepared via solid state reaction. High resolution X-ray powder diffraction was used to characterise the synthesised materials. It was found that low substitution (x = 0.1 and 0.2) of Ti4+ for Sc3+ gives a hexagonal perovskite structure, whereas high substitution (x = 0.5–0.7) results in a cubic perovskite structure. Thermogravimetric analysis revealed significant levels of protons in both as-prepared and hydrated samples. Electrical conductivity was measured by AC impedance methods under oxygen, argon and under dry and humid, both H2O and D2O, conditions for BaTi1−xScxO3−δ (x = 0.2, 0.6 and 0.7). In the temperature range of 150–600 \ub0C, under humid conditions, the conductivity is significantly higher than that under the dry conditions. The increase in conductivity is especially prominent for the cubic phases, indicating that protons are the dominant charge carriers. The proton conductivity of hexagonal BaTi0.8Sc0.2O3−δ is approx. two orders of magnitude lower than that of the more heavily substituted cubic phases. Conductivity is also found to be higher in dry O2 than in Ar in the whole temperature range of 150–1000 \ub0C, characteristic of a significant contribution from p-type charge carriers under oxidising atmospheres. Greater Sc3+ substitution leads to a higher proton concentration and the highest proton conductivity (σ [similar] 2 7 10−3 S cm−1 at 600 \ub0C) is found for the BaTi0.3Sc0.7O3−δ composition

Crystal structure, thermal expansion and high-temperature electrical conductivity of A-site deficient La2-zCo1+y(MgxNb1-x)1-yO6 double perovskites

New La-deficient double perovskites with P21/n symmetry, La∼1.90(Co2+1-xMg2+x)(Co3+1/3Nb5+2/3)O6 with x=0, 0.13 and 0.33, and La2(Co2+1/2Mg2+1/2) (Co3+1/2Nb5+1/2)O6 were prepared by solid state reaction at 1450 \ub0C. Their crystal structures were refined using time-of-flight neutron powder diffraction data. Our results show that certain cations such as Nb5+, with very strong B-O bonds in the perovskite structure, can induce A-site vacancies in double perovskites. Upon heating in N2 gas atmosphere at 1200 \ub0C ∼1% O atom vacancies are formed together with a partial reduction of the Co3+ content. The average thermal expansion coefficient between 25 and 900 \ub0C of La1.90(Co2+2/3Mg2+1/3)(Co3+1/3Nb5+2/3)O6 was determined to be 17.4 ppm K-1. Four-point electronic conductivity measurements showed that the compounds are semiconductors, with conductivities varying between 3.7\ub710-2 and 7.7\ub710-2 S cm-1 at 600 \ub0C and activation energies between 0.77 and 0.81 eV. Partial replacement of La3+ with Sr2+ does not lead to any increase of conductivity, while replacement of Mg2+ with Cu2+ in La1.9CoCu1/3Nb2/3O6 and La1.8CoCu1/2Nb1/2O6 leads to ∼100 times larger conductivities at 600 \ub0C, 0.35 and 1.0 S cm-1, respectively, and lower activation energies, 0.57 and 0.73 eV, respectively