Structural Evolution and High-Voltage Structural Stability of Li(Ni<sub><i>x</i></sub>Mn<sub><i>y</i></sub>Co<sub><i>z</i></sub>)O<sub>2</sub> Electrodes GoonetillekeDamian SharmaNeeraj PangWei Kong PetersonVanessa K. PetibonRemi LiJing DahnJ. R. 2018 Positive electrode materials remain a limiting factor for the energy density of lithium-ion batteries (LIBs). Improving the structural stability of these materials over a wider potential window presents an opportune path to higher energy density LIBs. Herein, operando neutron diffraction is used to elucidate the relationship between the structural evolution and electrochemical behavior for a series of Li-ion pouch cells containing Li­(Ni<sub><i>x</i></sub>Mn<sub><i>y</i></sub>Co<sub><i>z</i></sub>)­O<sub>2</sub> (<i>x</i> + <i>y</i> + <i>z</i> = 1) electrode chemistries. The structural stability of these electrodes during charge and discharge cycling across a wide potential window is found to be influenced by the ratio of transition-metal atoms in the material. Of the electrodes investigated in this study, the Li­(Ni<sub>0.4</sub>Mn<sub>0.4</sub>Co<sub>0.2</sub>)­O<sub>2</sub> composition exhibits the smallest magnitude of structural expansion and contraction during cycling while also providing favorable structural stability at high voltage. Greater structural change was observed in electrodes with a higher Ni content, while decreasing inversely to the Ni and Co content in the positive electrode. The combination of structural and electrochemical characterization of a wide range of NMC compositions provides useful insight for the design and application of ideal electrode compositions for long-term cycling and structural stability during storage at the charged state.