in battery technology have come since its fi rst demonstration, the high energy demands needed to electrify the automotive industry have not yet been met with the current technology. [ 2,3 ] One considerable bottleneck is the cathode energy density. [ 2,3 ] The lithium layered oxides utilize transition metal redox pairs for charge/ discharge compensation during lithium extraction and intercalation offering a theoretical capacity of 270 mAh g −1 for complete lithium extraction. [ 3,4 ] However, practical capacities have so far shown to be ≈200 mAh g −1 due to degradation reactions and large lattice contractions at low lithium content, limiting its capability to meet future demands. One possible cathode material is the Li-rich layered oxide compounds x Li 2 MnO 3 ⋅(1 − x )LiMO 2 (M = Ni, Mn, Co) (0.5 = < x = <1.0) that exhibit capacities over 280 mAh g −1 obtainable by the combination of the typical transition metal redox pair with the additional oxygen redox reaction as the charge compensation mechanism. [ 5 ] In this class of compounds, lithium ions can reside in both lithium layer and transition metal layer of close packed oxygen framework, typical from O3 type layered oxides like LiCoO 2 . Large irreversible capacities are often observed in these materials due to irreversible oxygen loss or side reactions stemming for the electrolyte. [ 6 ] It has been also observed using ex situ NMR (nuclear magnetic resonance) that lithium reinsertion back into the transition metal layer is little to none. [ 7 ] Several different lithium extraction/insertion sites and migration pathways are available, where lithium may be extracted from lithium or transition metal layers and lithium from octahedral coordinated sites to tetrahedral sites to form Li-Li dumbbells. [ 8 ] However, these studies have not revealed the dynamic process of lithium migration for the Li-rich material under operando electrochemical cycling conditions. Neutron scattering has several distinct advantages for battery studies: (1) The sensitivity of neutron to light elements such as lithium and oxygen is signifi cant in order to determine their position in the crystal structure; (2) Compares to the X-ray, the neutron shows larger scattering contrast between neighboring elements in the periodic table specifi cally the scattering lengths, e.g., for transition metals in this case: Ni, 10.3 fm; Mn, −3.73 fm; Co, 2.49 fm; and (3) The deep penetration capability of neutron allows simultaneous observation of the cathode and