Discovery of abnormal lithium-storage sites in molybdenum dioxide electrodes

Abstract

Developing electrode materials with high-energy densities is important for the development of lithium-ion batteries. Here, we demonstrate a mesoporous molybdenum dioxide material with abnormal lithium-storage sites, which exhibits a discharge capacity of 1,814 mAh g−1 for the first cycle, more than twice its theoretical value, and maintains its initial capacity after 50 cycles. Contrary to previous reports, we find that a mechanism for the high and reversible lithium-storage capacity of the mesoporous molybdenum dioxide electrode is not based on a conversion reaction. Insight into the electrochemical results, obtained by in situ X-ray absorption, scanning transmission electron microscopy analysis combined with electron energy loss spectroscopy and computational modelling indicates that the nanoscale pore engineering of this transition metal oxide enables an unexpected electrochemical mass storage reaction mechanism, and may provide a strategy for the design of cation storage materials for battery systems.

High rate hybrid MnO2@CNT fabric anodes for Li-ion batteries: properties and a lithium storage mechanism study by in situ synchrotron X-ray scattering

“…These results also indicate that the nanostructured surface of this hybrid is beneficial to store significant amount of lithium through an intercalation process by increasing lithium concentration in the oxide. A similar increase in lithium concentration has been observed in MoO3 anode, 61 for example. But, to the best of our knowledge, the present work provides the first evidence of Li-ion storage by intercalation for manganese oxide-based Li-ion anodes.…”

Alkaline earth metal vanadates as sodium-ion battery anodes

“…3c ), which is higher than the calculated value. This is because Na + insertion also leads to the formation of an amorphous phase (as evidenced by the ex situ TEM results) in addition to NaVO 2 and CaO nanograins, and the amorphous region provides additional active sites (such as vacant sites or void spaces) for Na ions 42 , 61 , resulting in the higher capacity. The capacity of CVO-450 is higher than that of CVO-550 at different current densities.…”

All-$t_{2g}$ Electronic Orbital Reconstruction of Monoclinic MoO$_2$ Battery Material

“…Interest in molybdenum oxides is particularly motivated by their application in a wide variety of fields such as flexible electronics, [9] solid fuel cells, [10] gas sensors, catalysis, diffusion barrier, [11] and storage lithium ion batteries. [12][13][14][15][16] Importantly, MoO 2 is considered to be one of the most studied anode systems for lithium ion batteries. [13,16] Both for fundamental science and for applications, MoO 2 is relevant in view of the quantum nature of its metallic conductivity [9,17] [18,19] This behavior is consistent with metal-metal dimerization parallel to the c-axis.…”