(Invited) Structure Reconstruction Strategy for High-Energy Lithium Ion Batteries without Capacity Sacrifice

Abstract

Lithium nickel oxides (LiNiO2) is considered to be a promising high-energy-density cathode material in lithium-ion batteries (LIBs)1-3. However, its inherent Li off-stoichiometry composition and structural deterioration under various phase transition usually bring about low initial capacity and rapid capacity decay4,5. To stimulate the high capacity and extend the lifespan for LiNiO2 in LIBs, the structure reconstruction method is applied to modify the cathode materials by Mo regulating (Mo-LiNiO2). The cross section high-resolution transmission electron microscope and energy dispersive spectroscopy (TEM-EDS) images show that the concentration of Mo is gradually decreased from the surface to the bulk center. Correspondingly, the concentrated Ni2+ ions in the surface of Mo-LiNiO2 build up the rock-salt phase layer with 5-20 nm in the surface, which plays the pinner effect based on in situ X-ray diffraction (XRD) patterns to enable excellent mechanical and structural reversibility for the layered Mo-LiNiO2 upon cycling. Finally, electrochemical results show that the modified cathode materials (Mo-LiNiO2) has a high capacity (~235 mAh g–1 at 0.1C) and the stable cycle performance (~94% for 90 cycles at 1C) as shown in Figure 1. The Mo-LiNiO2 cathode can provide high capacity and cycle stability with low material cost, which is suitable for the long service life of electric vehicles, further realizing a commercially viable cathode materials for LIBs.