Several yolk-shell-structured CuO-Fe2 O3 powders with various Cu/Fe molar ratios have been successfully prepared under equivalent reaction conditions using a one-pot spray pyrolysis process. The Cu and Fe components are uniformly distributed throughout the powders, irrespective of composition. The Brunauer-Emmett-Teller surface areas of the yolk-shell CuO-Fe2 O3 systems increased from 5 to 16 m(2) g(-1) if the Cu/Fe molar ratios are decreased from 3:1 to 1:3. The initial discharge and charge capacities of the yolk-shell CuO-Fe2 O3 system (Cu/Fe=1:2), showing maximum values at a constant current density of 1000 mA g(-1) , are 1436 and 1012 mA h g(-1) , respectively. After 130 cycles, the discharge capacities of the yolk-shell CuO-Fe2 O3 powders with Cu/Fe molar ratios of 1:3, 1:2, 1:1, 2:1, and 3:1 are 1159, 1151, 755, 655, and 651 mA h g(-1) , respectively. The discharge capacities of the yolk-shell and dense powder samples after 50 cycles, when subjected to a series of current density increases from 500 to 5000 mA g(-1) , are 735 and 495 mA h g(-1) , respectively.
Spherical C/Li 4 Ti 5 O 12 anode powders were prepared by spray pyrolysis with aqueous solution. The particle characteristics of C/Li 4 Ti 5 O 12 powders were determined by SEM, XRD and DTA-TG. C/Li 4 Ti 5 O 12 anode powder had a spherical morphology with non aggregation and porous structure. The carbon content was around 13 wt%. XRD analysis revealed that the spinel phase was obtained by heating at 750 °C under N 2 atmosphere. The discharge capacity of C/Li 4 Ti 5 O 12 was 160 mAh/g at 1C. That of C/Li 4 Ti 5 O 12 decreased to 90 mAh/g at 20 C. 96 % of initial discharge capacity was maintained at 1 C after 100 cycles. 85 % of it was maintained at 20 C after 300 cycles.
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