Synthesis and electrochemical properties of LiNi_(0.5-x)Cu_xMn_(1.5-y)Al_yO_4 (x = 0, 0.05, y = 0, 0.05) as 5 V spinel materials

摘要

The LiNi_(0.5-x)Cu_xMn_(1.5-y)Al_yO_4 (x = 0,0.05, y = 0,0.05) powders are synthesized by liquid co-precipitation and wet-milling. The doping effect on LiNio.5Mn1.5O4 by Al~(3+), Cu~(2+), and Al~(3+)/Cu~(2+) co-doping are investigated and compared in relation to physical and electrochemical characterization, namely, through X-ray diffraction, scanning electron microscopy, electronic conductivity, cyclic voltammetry and cycle tests. Results suggest that both Al~(3+) and Cu~(2+) doping effectively improve electrochemical performance of LiNi_(0.5)Mn_(1.5)O_4, although the effect is different between the two cations. All doped samples exceed 95% capacity retention after 100 cycles at room temperature compared to 92% retention for the undoped sample. Moreover, co-doped LiNi_(0.45)Cu_(0.05)Mn_(1.45)Al_(0.05)O_4 exhibits the best cyclic performance with slight superiority.