Synthesis and electrochemical performance of core-shell structured LiNi 0.5 Mn 1.5 O 4 microspheres for lithium ion batteries

The 5 V-cathode material LiNi 0.5 Mn 1.5 O 4 microspheres with hollow, solid or core-shelled inner structures for the lithium-ion batteries are designed and fabricated by a multi-step synthesis procedure. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) analysis, Fourier transformed infrared (FTIR) are employed to characterize the microstructures. Compared with the hollow and solid inner structures, the core-shell structured LiNi 0.5 Mn 1.5 O 4 exhibits excellent cycling stability and outstanding rate performance, which delivers a discharge capacity of 111.5 mA h g −1 after 200 cycles at 1 C, and 98 mA h g −1 at 8 C, respectively. Further analyses with cyclic voltammetry and electrochemical impedance spectroscopy demonstrate that the core-shell structure can provide structural stability and shortened lithium diffusion path at both room and elevated temperatures.