Structure and electrochemical behaviors of spherical Li1+xNi0.5Mn0.5O2+δ synthesized by rheological phase reaction method

摘要: Abstract Spherical layered Li 1+x Ni 0.5 Mn O 2+δ (x = 0, 0.1 and 0.2) materials are synthesized by rheological phase reaction method. X-ray diffraction patterns reveal that the prepared have α-NaFeO 2 structure with R-3m space group. The different lithium contents show distinct differences in structure, particle morphology, electrochemical property safety characteristics. When x = 0.1 0.2, excess resides transition metal layer to form MnO 3 -like structure. With content increasing from 1.0 1.2, initial discharge capacity Coulombic efficiency decreased, while maintenance is improved. ions electrochemically activated charge–discharge process has a contribution when cycling voltage window of 2.5–4.5 V for x = 0.2, leading high near 200 mAh g −1 excellent performance (with no decay after 100 cycles) at 20 mA g . Electrochemical impedance spectroscopy shows appropriate can decrease charge transfer resistance obviously several cycles. differential scanning calorimetric indicates generated heat increased increase x.