10.1021/acs.chemmater.8b03525.s001 Damian Goonetilleke Damian Goonetilleke Neeraj Sharma Neeraj Sharma Wei Kong Pang Wei Kong Pang Vanessa K. Peterson Vanessa K. Peterson Remi Petibon Remi Petibon Jing Li Jing Li J. R. Dahn J. R. Dahn 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 American Chemical Society 2018 stability discharge cycling Li-ion pouch cells Co content NMC compositions Structural Evolution Mn electrode compositions High-Voltage Structural Stability O 2 Electrodes energy density electrochemical characterization electrode materials Ni content electrochemical behavior energy density LIBs transition-metal atoms lithium-ion batteries operando neutron diffraction 2018-12-17 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/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/7562129 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.