An improved solid-state method for synthesizing LiNi0.5Mn1.5O4 cathode material for lithium ion batteries

High voltage LiNi0.5Mn1.5O4 cathode material was prepared by two steps solid-state method with additive PEG dispersant. XRD, SEM, XPS and electrochemical tests have been carried out, and the results show that the PEG can promote the pyrolysis of MnO2 and limit the impurities formation. The secondary particle can also be effectively restrained in the pre-calcination of MnO2 and NiO, and the effect can be last to the final product. The capacity from Mn3+/Mn4+ couple was reduced and the whole capacity can reach 140.7 mAh g−1 with the retention rate of 81.33% after 100 cycles at 0.2C. Meanwhile, the product has better rate performance and surface stability than those prepared by traditional two-step solid-state method.