Stabilized Li-rich Mn-based oxide cathode particles with an artificial surface in-Situ-preprocessing

Abstract

The heavy hybrid anion and cation redox contributes to high discharge capacity for Li-rich Mn-based cathode material, but also raises a number of issues including the low initial coulombic efficiency (ICE), rapid attenuation of capacity and voltage and so on, which have prevented its commercialization for more than a decade. Herein, solid-liquid impregnating is conducted to in-situ-build an artificial surface for Li1.2Mn0.54Ni0.13Co0.13O2 (FLLO) particles, which concurrently constructed a anion-redox-free LiMn1.5Ni0.5O4 (LNMO) shell during FLLO synthesis process that completely encloses the FLLO lattice (A-2%-LNMO-FLLO), presents as solid solution structure between FLLO and LNMO coating interface and exhibits stronger bonding between coatings and FLLO cathode material. DSC, TEM and industry computed tomography (ICT) evidence that LNMO coatings is effectiveness in stabilizing the crystal structure of FLLO from macro and micro aspects, leading to the excellent electrochemical properties, such as A-2%-LNMO-FLLO exhibits a discharge capacity of 278mAh/g under 0.1C, and the capacity retention is 98.5 % after 200 cycles under 1C. Furthermore, the enhancement mechanism on electrochemical properties is investigated from aspects of reaction process and crystal structure stability. This paper can provide a theoretical and experimental support for the practical application of FLLO cathode material.