Abstract
Layered oxides showing edge-sharing octahedra are promising negative electrode materials for high-power Li-ion batteries. In this sense, we propose the synthesis of the lamellar HTiNbO5 by solid-state (SS), sol-gel (SG) and exfoliation-restacking (NS) syntheses investigating in the same way the charge storage mechanism of this oxide and the influence of the microstructure on material and electrochemical properties. An arsenal of characterization techniques has been used to investigate these three types of particles using X-Ray Diffraction (XRD), electron microscopy, but also by associating mass spectroscopy to thermogravimetric analyses (TGA). Their ability to intercalate lithium has been compared, showing interesting and very similar specific capacities for solid-state and sol-gel synthesis (> 100 mAh.g − 1 at 0.5 A.g − 1). In addition, it was shown that the synthesis giving rise to nanosheet (NS) led to lower performance due to the presence of organic molecules in the interlayer spacing of the 2D lamellar structure. Lastly, in situ XRD evidenced a solid-solution reaction for HTiNbO5, with an initial and irreversible phase change leading to the formation of Li0.4HTiNbO5. Moreover, ex situ1H MAS NMR measurements highlight the essential role of the proton in the charge storage mechanism of HTiNbO5. Thus, this paper demonstrates the interest of HTiNbO5 as a fast negative electrode material for high-power Li-ion batteries as well as the predominant role that the proton can play in the diffusion of lithium ions inside a confined interlayer space.
Published Version
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