Fundamental understanding of high-capacity lithium-excess cathodes with disordered rock salt structure

As a new class of lithium rich cathodes,disordered rock-salt cathodes have been of primary interest,because of their ability to deliver a promisingly high capacity up to 300 mAh/g.Nevertheless,some fundamental issues are yet to be fully understood and a comprehensive mastering of their solid-state chemistry,kinetics and thermal stability is required.Here,we select a high capacity cation-disordered positive electrode-Li_(1.2)Ni_(0.4)Nb_(0.4)O_(2)as a model compound to study intrinsic reaction mechanism,including charge compensation mechanism,kinetics,thermal stability,and structural evolution.By combining soft and hard X-ray absorption spectroscopy(XAS),X-ray photoelectron spectroscopy(XPS)with operando and exsitu differential scanning calorimetry(DSC),galvanostatic intermittent titration technique(GITT),cyclic voltammetry(CV),and X-ray diffraction(XRD),we present holistic information on disordered rock-salt cathode.This work provides beneficial insights into designing and tailoring new positive electrodes with disordered rock-salt structure.