Improved electrochemical properties of a coin cell using LiMn₁.₅Ni₀.₅O₄ as cathode in the 5 V range

By Singhal, Rahul; Das, Suprem R.; Oviedo, Osbert; Tomar, Maharaj S. & Katiyar, Ram S.
Published in Journal of Power Sources NULL 2006

Abstract

Phase pure LiMn₁.₅Ni₀.₅O₄ powders were synthesized by a chemical synthesis route and were subsequently characterized as cathode materials in a Li-ion coin cell comprising a Li anode and lithium hexafluorophosphate (LiPF₆), dissolved in dimethyl carbonate (DMC) + ethylene carbonate (EC) [1:1, v/v ratio] as electrolyte. The spinel structure and phase purity of the powders were characterized using X-ray diffraction and micro-Raman spectroscopy. The presence of both oxidation and reduction peaks in the cyclic voltammogram revealed Li+ extraction and insertion from the spinel structure. The charge–discharge characteristics of the coin cell were performed in the 3.0–4.8 V range. An initial discharge capacity of ∼140 mAh g⁻¹ was obtained with 94% initial discharge capacity retention after 50 repeated cycles. The microstructures and compositions of the cathode before and after electrochemistry were investigated using scanning electron microscopy and energy-dispersive analysis by X-ray analysis, respectively. Using X-ray diffraction, Raman spectroscopy and electrochemical analysis, we correlated the structural stability and the electrochemical performance of this cathode.

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