Mg–Al–B co-substitution LiNi0.5Co0.2Mn0.3O2 cathode materials with improved cycling performance for lithium-ion battery under high cutoff voltage

Abstract

ABSTRACT In order to investigate the influences of Mg–Al–B co-substitution on LiNi 0.5 Co 0.2 Mn 0.3 O 2 material, the uniform and spherical doped Li[Ni 0.5 Co 0.2 Mn 0.3 ] 0.992 Mg 0.003 Al 0.003 B 0.002 O 2 material is successfully prepared through a simple solid state synthesis. X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) mapping, X-ray photoelectron spectroscopy (XPS) and electrochemical tests have been applied for material characterizations and electrochemical measurements. Through the result of XRD and the Rietveld refinements, Mg, Al and B atoms may be incorporated into the crystal lattice. Similarly, the results of EDX and XPS confirm the existence of Mg 2+ , Al 3+ and B 3+ in accordance with the chemical formula. The Mg–Al–B co-substitution LiNi 0.5 Co 0.2 Mn 0.3 O 2 material shows excellent electrochemical performance, especially the superior cycling stability under high cutoff voltages. The Mg–Al–B co-substitution LiNi 0.5 Co 0.2 Mn 0.3 O 2 material exhibits the higher capacity retentions of 83.8%, 84.9%, 83.2% and 80.4% than that of the bare one (71%, 62.5%, 40.9% and 25%) after 200 cycles at a cutoff voltage of 4.2, 4.3, 4.4 and 4.5 V, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirm that the modification of Mg–Al–B co-substitution plays an important role in improving the electrochemical performance of the bare LiNi 0.5 Co 0.2 Mn 0.3 O 2 .