Incorporation of Alloy-de-Alloy Phase with Conversion Based Manganese Oxide to Enable High and Stable Capacity and Density Functional Theory Study of CdMn2O4

Abstract

In this work, incorporation of alloying-dealloying based element i.e. Cd due to its high ductility and good wear resistance in manganese based spinel oxides i.e. CdMn2O4 has been studied as Li-ion battery (LIB) anode. This study demonstrates that the Li-alloying phases in such type of compound provides extra assistances of dissemination of these intermetallics element in Li2O matrix which stabilizes the conversion reaction and significantly buffer the accompanying volume variation. As a result, CdMn2O4 exhibits high-capacity (810 (±5) mAh g−1, 100 mA g−1) and -rate capability at different C-rates that signifies the introduction of an alloying element over pure conversion based materials. Further, reduced particle size of ∼ 10 nm supports mechanical integrity of electrode by transferring the developed stress to voids/gaps in spinel CdMn2O4 enabling high performance as LIB anodes. Based on the galvanostatic, cyclic voltammetry data and ex situ –X-ray diffraction,-transmission electron microscope, -selected area electron diffraction studies, a plausible reaction mechanism is also proposed. The reversibility of proposed reaction is further complemented by electrochemical impedance spectroscopy. Furthermore, diffusion of Li ion into spinel CdMn2O4 and associated structural and electronically changes are studied by Density Functional Theory (DFT) and discussed in detail.