Relieving capacity decay and voltage fading of Li1.2Ni0.13Co0.13Mn0.54O2 by Mg2+ and PO43- dual doping

Abstract Li- and Mn-rich layered cathode materials (LMR) have been widely studied for their ultrahigh energy density. Unfortunately, the rapid potential decay and capacity degradation during cycling hinder their commercialization process. In this work, Mg2+ cation and PO43− polyanion dual elements coupling effect induced lattice modification strategy is developed to address these drawbacks for a typical lithium-rich material. The structural characteristic, chemical composition, valence state and elemental distribution of the materials are investigated by scanning electron microscopy, X-ray diffraction, inductively coupled plasma optical emission spectroscopy, focused ion beam and high-resolution transmission electron microscopy, respectively. Mg2+ and PO43− co-modified lithium-rich cathode material shows excellent electrochemical properties. It provides an improved initial coulombic efficiency of 87 % and ultrahigh initial discharge capacity of 307 mA h g-1 during a cut-off voltage of 2.0–4.8 V and a current density of 25 mA g-1. In conclusion, the Mg2+ and PO43− co-modified material exhibits not only significantly improved rate performance (150.7 mA h g−1 @ 5 C) but also markedly improved cycling stability (83 % @ 1 C @ 300 cycles).