An Exploratory Investigation of Spinel LiMn 1.5 Ni 0.5 O 4 as Cathode Material for Potassium‐Ion Battery
Résumé
The emerging interest in K-ion batteries (KIBs) increases the importance of cathodes with high working voltage in this system. The LiMn1.5Ni0.5O4 spinel is a promising alternative for the next generation of high voltage Li-ion positive electrodes and its delithiated structure could be of interest for KIBs. In this work, Li ions are extracted from LiMn1.5Ni0.5O4 by a first electrochemical oxidation. The electroformed λ-Mn0.75Ni0.25O2 spinel phase is shown to convert into layered K0.5Mn0.75Ni0.25O2 (KMNO) at 20°C along the first discharge in K cell. Then, 0.3 K + /KNMO (90 mAh g-1) are reversibly exchanged during the subsequent cycle. Superior electrochemical performance are reported for KMNO as compared to K0.5MnO2 (KMO): a higher working voltage vs. K + /K (3.10 V vs. 2.79 V), enhanced rate capability and better cycling stability (70 mAh g-1 after 60 cycles at C/20 for KMNO vs. 40 mAh g-1 for KMO). The contribution of the Ni redox system is revealed as a reason for these improved performances.
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)
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