Li1.1Na0.1Mn0.534Ni0.133Co0.133O2 as cathode with ameliorated electrochemical performance based on dual Li+/Na+ electrolyte

Abstract

Layered Li-rich cathode materials Li1.2Mn0.534Ni0.133Co0.133O2 (LNCMN-0) and Na doping Li1.1Na0.1Mn0.534Ni0.133Co0.133O2 (LNCMN-0.1) are prepared successfully by a co-precipitation method and several consecutive calcination treatments. Besides, the phase structure, morphology, and electrochemical properties of the four samples are studied in detail using X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charge-discharge test, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Although the discharge capacity of spherical LNCMN-0.1 decreases slightly at 0.1 C (1 C = 250 mA g−1), compared to the pristine LNCMN-0, it is noteworthy that the LNCMN-0.1 matched with dual Li+/Na+ electrolyte exhibit superior stability performance at 1 C, as well as enhanced rate capability. The LNCMN-0.1 (Li+/Na+) delivers an initial discharge specific capacity of 267.61 mAh g−1 at 0.1 C between 2.0 and 4.8 V at room temperature and initial coulombic efficiency of 83.51%, which is higher than the LNCMN-0 samples (76.42 and 81.54%). The experimental results verify that Na doping combined with dual Li+/Na+ electrolyte can generate a synergistic effect, which is a promising idea to ameliorate the electrochemical performance for this material.