Structural and Electrochemical Characterization of LiNi_0.5Mn_0.5O₂

Abstract

The initial charge/discharge behavior of LiNi_0.5Mn_0.5O₂ has been examined by XRD, in-situ XAFS and electrochemical methods. The LiNi_0.5Mn_0.5O₂ (a=2.8999(7), c=14.330(7)Å in hexagonal setting) was observed to keep its initial structure after charging up to 4.5V. XAFS analysis revealed that the majority of Ni and Mn exist in a divalent and tetravalent state respectively. Upon charging LiNi_0.5Mn_0.5O₂, Ni⁺ ions were consequently oxidized to Ni⁴⁺.