Reaction mechanism and additional lithium storage of mesoporous MnO2 anode in Li batteries

Nanostructured transition metal oxides, employed as anode materials for lithium-ion batteries, exhibit a higher capacity than the theoretical capacity based on the conversion reaction. To date, the reasons behind this phenomenon are unclear. For the one-step evolution of anode material for lithium-ion batteries, it is essential to understand the lithium storage reaction mechanism of the anode material. Herein, we provide a detailed report on the lithium storage and release mechanism of MnO2, using synchrotron-based X-ray techniques. X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge, MnO2 is reduced in the order of MnO2 → LixMnO2 (1