Modification of the electrochemical activity of LiMn_(1.95)Si_(0.05)O4spinel via addition of phases with different physico-chemical properties

摘要

We report the synthesis of composites based on freeze-dried LiMn_(1.95)Si_(0.05)O4 spinel. In order to improve the active material-electrolyte interface for better cyclability, three different additive materials were chosen: LiMn_(1.9)Ga_(0.1)O4, Al2O3 and Li3PO4. A morphologic examination of the composites demonstrated a good connection of the homogeneous primary particles about 50 nm in diameter and the different additive materials, especially when adding LiMn_(1.9)Ga_(0.1)O4 and Al2O3. The nature of the additives was confirmed by XPS and magnetic measurements. The electrochemical study revealed that LiMn_(1.9)Ga_(0.1)O4 is a suitable complement to LiMn_(1.95)Si_(0.05)O4. Due to the similar transport properties, the concurrence of both differently substituted spinels in the electrode material has a synergistic effect favoring the electrochemical response of the cathode composite.