Crystal structure and cathode properties of delithiated Li1-xMn1/3Ni1/3Co1/3O2 for Mg rechargeable batteries
Abstract The crystal structure and electrode properties of delithiated Li1-xMn1/3Ni1/3Co1/3O2 as a Mg rechargeable battery cathode material were investigated. Electrochemically delithiated Li0.3Mn1/3Ni1/3Co1/3O2 and Li0.4Mn1/3Ni1/3Co1/3O2 in a Mg cell exhibited capacities of approximately 50 and 80 mAh g−1, respectively. On the other hand, chemically delithiated Li0.1Mn1/3Ni1/3Co1/3O2 and Li0.4Mn1/3Ni1/3Co1/3O2 exhibited capacities of approximately 40 and 130 mAh g−1, respectively. Synchrotron X-ray diffraction was performed to refine the crystal structure of these two chemically delithiated samples and their crystal structures were analyzed in detail. Although Li0.4Mn1/3Ni1/3Co1/3O2 was identified as a monophase of a hexagonal crystal system (R 3 ¯ m), Li0.1Mn1/3Ni1/3Co1/3O2 was identified as two phases of the hexagonal O3-type (R 3 ¯ m) and the trigonal O1-type (P 3 ¯ m1). Therefore, the Li deficient O3 structure is considered to be more suitable than O1 structure in the electrochemical intercalation and deintercalation of Mg ions.