A series of Ni substituted spinel LiNi x Mn2−x O4 (0≤ x ≤0.5) have been synthesized to study the evolution of the local structure and their electrochemical properties. X-ray diffraction showed a few Ni cations moved to the 8a sites in heavily substituted LiNi x Mn2−x O4 (x ≥0.3). X-ray photoelectron spectroscopy confirmed Ni2+ cations were partially oxidized to Ni3+. The local structures of LiNi x Mn2−x O4 were studied by analyzing the F 2 g ( 1 ) and A1g Raman bands. The most compact [Mn(Ni)O6] octahedron with the highest bond energy of Mn(Ni)O was found for LiNi0.2Mn1.8O4, which showed a Mn(Ni)O average bond length of 1.790Å, and a force constant of 2.966Ncm−1. Electrolyte decomposition during the electrochemical charging processes increased with Ni substitution. The discharge capacities at the 4.1 and 4.7V plateaus obeyed the linear relationships with respect to the Ni substitution with the slopes of −1.9 and +1.9, which were smaller than the theoretical values of −2 and +2, respectively. The smaller slopes could be attributed to the electrochemical hysteresis and the presence of Ni3+ in the materials.