Study of spherical Li1.2-xNaxMn0.534Ni0.133Co0.133O2 cathode based on dual Li+/Na+ transport system for Li-ion batteries

Abstract

The Na-doped layered Li1.2-xNaxMn0.534Ni0.133Co0.133O2 (x = 0, 0.05, 0.1 and 0.15) cathode materials with porous spherical structure for lithium-ion batteries have been successfully prepared via a facile co-precipitation method. The dual Li+/Na+ transport system is Li1.2-xNaxMn0.534Ni0.133Co0.133O2 cathode materials companying with dual Li+/Na+ electrolyte, which exhibits an improved initial charge-discharge efficiency, cycling stability and rate capability, compared with pristine Li1.2Mn0.534Ni0.133Co0.133O2. Electrochemical results verify that Li1.1Na0.1Mn0.534Ni0.133Co0.133O2 delivers the initial charge/discharge capacity of 329.68/277.86 mAh g−1 with improved initial coulombic efficiency of 84.28% at 0.1C, and shows good cycling performance with a capacity retention of 76.5% after 100 cycles at 1C much higher than 37.9% of the pristine sample. Such outstanding performance of Li1.2-xNaxMn0.534Ni0.133Co0.133O2 is mainly attributed to: on the one hand, the small particle size and porous structure are helpful to increase the electrochemical active surface, shorten dual Li+/Na+ diffusion pathway, thus enhancing the energy storage properties. On the other hand, the design of dual Li+/Na+ transport system enables to enlarge interlayer, stabilize crystal structure and exert mutual diffusion or transportation of Li+ and Na+.