Fig. 2: Structural evolution of the LRM cathode during the first cycle.
a First charge/discharge curves of a graphite || LRM pouch cell and corresponding surface contour plot recorded using operando neutron diffraction. Contributions of LRM are marked by arrows. b Phase fraction evolution during the first cycle. Purple: O3’; yellow: O3; blue: spinel. c Values of dinter-layer and dintra-layer for the O3’ and O3 phases in the LRM cathode obtained from Rietveld refinement as a function of cycling time. (In the hexagonal crystal system, \({(003)}_{o3}\) is equivalent to \({(001)}_{o3}\) in the monoclinic system. Therefore, dinter-layer corresponds to \({{{{\rm{d}}}}}_{{(003)}_{o3}}\) and \({{{{\rm{d}}}}}_{{(001)}_{o3{\prime} }}\). Similarly, \({(100)}_{o3}\), \({(010)}_{o3}\) and \({(1\bar{1}\,0)}_{o3}\) are equivalent to \({(13\,\bar{1/3})}_{o3{\prime} }\), \({(\bar{1}\,31/3)}_{o3{\prime} }\) and \((20\,\bar{2/3})_{o3{\prime} }\), respectively. Therefore, dintra-layer corresponds to \([{{{{\rm{d}}}}}_{(100)_{o3}}+{{{{\rm{d}}}}}_{(010)_{o3}}+{{{{\rm{d}}}}}_{{(1\,\bar{1}\,0)}_{o3}}]\,/\,3\) in the O3 phase and to \([{{{{\rm{d}}}}}_{(13\,\bar{1/3})_{o3{\prime} }}+{{{{\rm{d}}}}}_{(\bar{1}\,31/3)_{o3{\prime} }}+\,{{{{\rm{d}}}}}_{(20\,\bar{2/3})_{o3{\prime} }}]\,/\,3\) in the O3’ phase. d Calculated ratio of DoO (Li@TM6), DoD (LiO2) and O vacancy plotted as a function of cycling time. e Schematic diagram of the Li@TM6 superstructure in the O3’ phase, in which Li and TM at the TMO2 slabs occupy 2b and 4g Wyckoff sites, respectively.
