High Rate Capability of 5 V LiNi0.5Mn1.5O4 Cathode Materials Synthesized via a Gel-Combustion Method

Sub. micron LiNi0.5Mn1.5O4 with excellent high rate performance was synthesized by a polyvinylpyrrolidone. assisted gel. combustion method. Thermogravimetric and differential thermal analyses (TG/DTA) were used to determine the nature of the combustion process of the gel. The structure and morphology of the as. prepared materials were characterized by X. ray diffraction (XRD), scanning electron microscopy (SEM), and cyclic voltammetry (CV). The results showed that the LiNi0.5Mn1.5O4 powders were single-phase spinel and consisted of uniform secondary particles (5 mu m), which were formed by small primary particles (500 nm). Galvanostatic charge. discharge tests indicated that the LiNi0.5Mn1.5O4 had an excellent rate capability and cyclic performance. When discharged at a rate of 0.5C, 1C, 4C, 8C, and 10C between 3.5 and 4.9 V, the discharge capacity is 131.9, 127.6, 123.4, 118.4, and 113.7 mAh . g(-1), respectively. Upon long cycling under a high discharge rate of 10C, the capacity retentions after 100, 500, and 1000 cycles were 91.4%, 80.9%, and 73.5%, respectively.