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Abstract: A new material, LiRu2O4, has been synthesized by ion-exchange reaction from NaRu2O4 that has been prepared by solid state reaction at 950 °C under Ar flow. The crystal structure of LiRu2O4, isostructural with the parent NaRu2O4, has been refined by an X-ray Rietveld method (Pnma, a = 9.13940(5) Å, b = 2.80070(9) Å, c = 11.0017(1) Å, Z = 4, R p = 5.30%, wR p = 6.73%, χ 2 = 0.41, 23 °C). The structure belongs to CaFe2O4-type, where double chains of edge-sharing octahedral RuO6 share the corners with neighboring double chains and form tunnels in between them parallel to the shortest b-axis so that the one-dimensional Li array is placed inside each of the tunnels. Detailed structural analysis indicates that the tunnel inside has more than enough space to be filled with the Li atoms. The electrochemical tests of LiRu2O4 demonstrates a reversible Li intercalation reaction at 3.2–3.5 V vs. Li/Li+ with a capacity of ∼80 mAhg−1. The material exhibits excellent high-rate characteristics (93% capacity retention at 10C/1C) as well as high capacity retention with cycles (99% at 50 cycles). [Copyright &y& Elsevier]

NASICON-type structured Na 3 V 2 O 2 (PO 4 ) 2 F nanocubes with multi-wall carbon nanotubes (MWCNTs) composite has been synthesized by ethylene glycol-assisted hydrothermal reaction and used as a rechargeable non-aqueous and aqueous sodium-ion battery cathode material. As a cathode material for non-aqueous sodium-ion batteries, as-synthesized Na 3 V 2 O 2 (PO 4 ) 2 F-MWCNT composite shows stable capacity of 98 mAh g −1 at 0.1 C for 120 cycles and 60 mAh g −1 at 2 C for 1800 cycles in half-cell and full-cell configurations, respectively. In aqueous electrolytes, Na 3 V 2 O 2 (PO 4 ) 2 F-MWCNT composite delivers discharge capacity of 35 mAh g −1 at 1 C rate in half-cell and 42 mAh g −1 at 1 C rate in full-cell with NaTi 2 (PO 4 ) 3 -MWCNT as an anode. Stable cyclability and high rate performance of Na 3 V 2 O 2 (PO 4 ) 2 F-MWCNT nanocomposite can be attributed to the very short sodium ion diffusion length in nano cube morphology of Na 3 V 2 O 2 (PO 4 ) 2 F as well as the carbon nanotubes matrix which endows the unbreakable conductive networks for electrons and Na + ions. [ABSTRACT FROM AUTHOR]

The slow kinetics of bigger-sized sodium ions in intercalation compounds restricts the practical applications of sodium batteries. In this work, sodium ion intercalation/de-intercalation behavior of Na0.44MnO2 (NMO), which is one of the promising cathode materials for sodium batteries, is presented in both aqueous and non-aqueous electrolyte systems. The NMO samples synthesized using modified Pechini method shows better rate capability in 0.5 M sodium sulfate aqueous electrolyte system than the 1 M sodium perchlorate non-aqueous system. The difference in the rate performance is extensively investigated using electrochemical impedance spectroscopy (EIS) measurements and the apparent diffusion coefficients of sodium in NMO are determined to be in the range of 1.08 × 10−13 to 9.15 × 10−12 cm2 s−1 in aqueous system and in the range of 5.75 × 10−16 to 2.14 × 10−14 cm2 s−1 in non-aqueous systems. The differences in the evaluated rate capability are mainly attributed to nearly two to three orders of magnitude difference in the apparent diffusion coefficient along with the charge transfer resistance and the resistance from the formed SEI layer. [ABSTRACT FROM AUTHOR]

Abstract: One-dimensional ordered LiNi0.5Mn1.5O4 nanorods have been fabricated and investigated for use as a high power cathode in rechargeable Li-ion batteries. These highly crystalline nanorods, with an ordered spinel structure and diameters and lengths around 130nm and 1.2μm, respectively, were synthesized in two steps by using a hydrothermal reaction to produce β-MnO2 nanorods followed by solid-state lithiation. Electrochemical analysis showed the superior performance of nanorods as a cathode in Li-ion half cells. The specific charge and discharge capacities were found to be 120 and 116mAhg−1 at a 0.5C rate, and 114 and 111mAhg−1 at a 1C rate between 3.5 and 5.0V vs. Li+/Li. Moreover, the nanorods exhibit high power capability, maintaining capacities of 103 and 95mAhg−1 at specific currents of 732.5 and 1465mAg−1 (5 and 10C rates), respectively. [Copyright &y& Elsevier]

Abstract: Fe- and Cu-doped SmBaCo2O5+δ (FC-SBCO)–Ce0.9Gd0.1O1.95 (CGO) composites with various CGO contents (0–40wt.%) are investigated as new cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on a Ce0.9Gd0.1O1.95 electrolyte. The effect of CGO incorporation on the thermal expansion coefficient (TEC), electrochemical properties and thermal stability of the FC-SBCO-CGO composites is investigated. A composite cathode of 30wt.% CGO–70wt.% FC-SBCO (CS30-70) coated on a Ce0.9Gd0.1O1.95 electrolyte shows the lowest area specific resistance (ASR), i.e., 0.049Ωcm2 at 700°C. The TEC of the CS30-70 cathode is 14.1×10−6 °C−1 up to 900°C, which is a lower value than that of the FC-SBCO (16.6×10−6 °C−1) counterpart. Long-term thermal stability and thermal cycle tests of the CS30-70 cathode are performed. Stable ARS values are observed during both type of test. An electrolyte-supported (300-μm thick) single-cell configuration of CS30-70/CGO/Ni-CGO delivers a maximum power density of 535mWcm−2 at 700°C. The unique composite composition of CS30-70 demonstrates improved electrochemical performance and good thermal stability for IT-SOFCs. [ABSTRACT FROM AUTHOR]