The ability to control the formation of nano-sized domains of Ni/Mn cation order by annealing of LiNi0.5Mn1.5O4 (LNMO) spinel oxide, a next-generation cathode material, was revealed using neutron, x-ray, and electron diffraction. The work demonstrates a correlation between the degree of nanoscale cation order in LNMO and Li-ion battery performance. Partially ordered LNMO delivers the optimal performance by balancing the higher capacity of the fully ordered phase with the superior cycling performance of the disordered phase.

Neutron diffraction data provide information about volume-averaged size and fraction of ordered domains. Electrochemical behavior of LNMO agrees with calculations using density functional theory performed with varying degrees of chemical ordering. Annealing LNMO at 700oC for 2 hours provides the optimal electrochemical properties of LNMO.

Work performed at the ORNL Spallation Neutron Source’s Powder Diffractometer (POWGEN) was supported by Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.

Phases in LiNi0.5Mn1.5O4 for Li-Ion Batteries.” Chemistry of Materials. 26: 15 (2014): 4377–4386. http://pubs.acs.org/doi/abs/10.1021/cm501203r