Li-storage and cycling properties of spinel, CdFe2O4, as an anode for lithium ion batteries

Abstract

Cadmium ferrite, CdFe2O4, is synthesized by urea combustion method followed by calcination at 900°C and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) techniques. The Li-storage and cycling behaviour are examined by galvanostatic cycling, cyclic voltammetry (CV) and impedance spectroscopy in the voltage range, 0005-3 0 V vs Li at room temperature. CdFe2O 4 shows a first cycle reversible capacity of 870 (± 10) mAhg-1 at 007C-rate, but the capacity degrades at 4 mAhg-1 per cycle and retains only 680 (± 10) mAhg-1 after 50 cycles. Heat-treated electrode of CdFe2O4 (300°C; 12 h, Ar) shows a significantly improved cycling performance under the above cycling conditions and a stable capacity of 810 (± 10) mAhg-1 corresponding to 87 moles of Li per mole of CdFe2O4 (vs theoretical, 90 moles of Li) is maintained up to 60 cycles, with a coulombic efficiency, 96-98%. Rate capability of heat-treated CdFe2O 4 is also good: reversible capacities of 650 (± 10) and 450 (± 10) mAhg-1 at 05 C and 14 C (1 C = 840 mAg-1) are observed, respectively. The reasons for the improved cycling performance are discussed. From the CV data in 2-15 cycles, the average discharge potential is measured to be ∼ 09 V, whereas the charge potential is ∼21 V. Based on the galvanostatic and CV data, ex situ-XRD, -TEM and -SAED studies, a reaction mechanism is proposed. The impedance parameters as a function of voltage during the 1st cycle have been evaluated and interpreted. © Indian Academy of Sciences.