Improved electrochemical performances of layered lithium rich oxide 0.6Li[Li1/3Mn2/3]O-2 center dot 0.4LiMn(5/12) Ni5/12Co1/6O2 by Zr doping

摘要

A series of layered lithium-rich oxides 0.6Li[Li1/3Mn2/3(1-x) Zr-2/3x]O-2 center dot 0.4LiMn(5/12)Ni(5/12)Co(1/6)O(2) (0 <= x <= 10%) have been prepared by a spray-dry method. The crystal structural and morphological properties of all the samples have been studied by XRD, XPS, SEM, HRTEM and SAED. XRD results reveal Zr4+ ions are doped into the lattice. HRTEM results suggest Zr4+ ions can stabilize the layered structural feature during cycles. The electrochemical properties are remarkably upgraded by Zr4+ ion doping. The discharge capacity of Zr4% doped samples remains 218.9 mA h g(-1) after 100 cycles with a capacity retention of 84% at 20 mA g(-1) between 2.0 and 4.8 V, while the undoped samples drop to 168.6 mA h g(-1) with a capacity retention of 72%. Moreover, Zr4% doped samples show the lowest voltage decay, about 0.16 V lower than the undoped samples after 100 cycles. This study suggests suitable Zr4+ doping can improve the electrochemical performances and suppress voltage decay for layered lithium-rich oxides.