Structural and Electrochemical Properties of Ba-doped Li[Ni0.5Mn1.5]O-4 Electrode Synthesized by Co-precipitation for 5.0V Lithium-Ion Batteries

摘要

Li[Ni0.5Mn1.5]O-4 is considered as one of the most attractive cathode materials for high-power battery applications owing to its high operating voltage of around 5.0 V vs. Li/Li+, excellent reversible capacity, and superior specific energy. However, Li[Ni0.5Mn1.5]O-4 exhibits a non-negligible capacity fading during cycling due to the structural and the chemical instabilities resulting from electrolyte decomposition. Ba doping significantly reduced the degree of Ni/Mn disordering, decreased the charge-transfer resistance, and accelerated lithium diffusion owing to the strong binding energy of Ba2+-O (563 eV). We investigated the effect of Ba doping on the crystalline structure and the electrochemical performance of the Li[Ni0.5Mn1.5]O-4 cathode material. The Ba-doped cathode exhibited a good charge storage capacity of 119 mAhg(-1), with a capacity retention of over 94% after 35 voltage cycles (between 3.0 and 5.0 V) at 0.1 C.