Study of the Insertion/Deinsertion Mechanism of Sodium into Na0.44MnO2

作者：Frédéric Sauvage, Lydia Laffont, J.-M. Tarascon, Emmanuel Baudrin · 发表于：Inorganic Chemistry · 年份：2007 · DOI：10.1021/ic0700250 · 被引用次数：465 · 研究领域：Multiferroics and related materials、Ferroelectric and Piezoelectric Materials、Transition Metal Oxide Nanomaterials

Pure Na0.44MnO2 samples were prepared via a solid-state route by carefully tuning the synthesis conditions. Insertion/deinsertion of sodium into the well-crystallized particles leads to capacities as high as 140 mA.h/g. A potentiostatic intermittent titration technic, together with in situ X-ray diffraction measurements, enabled us to evidence the presence of six biphasic transitions within a potential range of 2-3.8 V (vs Na+/Na). The insertion process within the NaxMnO2 system is fully reversible over the 0.25 < x < 0.65 composition range and presents some degree of irreversibility as values of x below 0.25 are reached. Furthermore, we similarly showed that HCl treatment has a detrimental effect on these electrochemical properties because of structural and textural evolutions.