The Effects of Ru(4+) Doping on LiNi(0.5)Mn(1.5)O(4) with Two Crystal Structures

Doping of Ru has been used to enhance the performance of LiNi(0.5)Mn(1.5)O(4) cathode materials. However, the effects of Ru doping on the two types of LiNi(0.5)Mn(1.5)O(4) are rarely studied. In this study, Ru(4+) with a stoichiometric ratio of 0.05 is introduced into LiNi(0.5)Mn(1.5)O(4) with different space groups (Fd [Formula: see text] m, P4(3)32). The influence of Ru doping on the properties of LiNi(0.5)Mn(1.5)O(4) (Fd [Formula: see text] m, P4(3)32) is comprehensively studied using multiple techniques such as XRD, Raman, and SEM methods. Electrochemical tests show that Ru(4+)-doped LiNi(0.5)Mn(1.5)O(4) (P4(3)32) delivers the optimal electrochemical performance. Its initial specific capacity reaches 132.8 mAh g(−1), and 97.7% of this is retained after 300 cycles at a 1 C rate at room temperature. Even at a rate of 10 C, the capacity of Ru(4+)-LiNi(0.5)Mn(1.5)O(4) (P4(3)32) is still 100.7 mAh g(−1). Raman spectroscopy shows that the Ni/Mn arrangement of Ru(4+)-LiNi(0.5)Mn(1.5)O(4) (Fd [Formula: see text] m) is not significantly affected by Ru(4+) doping. However, LiNi(0.5)Mn(1.5)O(4) (P4(3)32) is transformed to semi-ordered LiNi(0.5)Mn(1.5)O(4) after the incorporation of Ru(4+). Ru(4+) doping hinders the ordering process of Ni/Mn during the heat treatment process, to an extent.