High-Voltage Performance of Li[Ni0.55Co0.15Mn0.30]O-2 Positive Electrode Material for Rechargeable Li-Ion Batteries

Abstract

The electrochemical properties and thermal stabilities of a new positive electrode material for Li-ion batteries, Li[Ni0.55Co0.15Mn0.30]O-2, were investigated over a wide potential window. This electrode material was synthesized via a coprecipitation method. X-ray diffraction studies indicated that the synthesized material crystallized into an alpha-NaFeO2 layered structure (R (3) over barm). The Li[Ni0.55Co0.15Mn0.30]O-2 positive electrode has a discharge capacity of 202 mAh g(-1) in the voltage range of 2.7-4.5 V. This high capacity was retained throughout cycling. The thermal stability of Li[Ni0.55Co0.15Mn0.30]O-2 was measured by differential thermal calorimetry and found to be comparable to that of Li[Ni1/3Co1/3Mn1/3]O-2. This positive electrode material was also characterized in a full cell configuration (graphite negative electrode) by the hybrid pulse power characterization tests following the FreedomCAR battery test manual for plug-in hybrid electric vehicles (PHEVs). The pulse power capability and available energy met the goals for PHEVs.