TY - JOUR AU - Wang Hay Kan AU - Biao Deng AU - Yahong Xu AU - Alpesh Khushalcha Shukla AU - Tao Bo AU - Shuo Zhang AU - Jin Liu AU - Piero Pianetta AU - Bao-Tian Wang AU - Yijin Liu AU - Guoying Chen AB -

We report the observation of persistent chemical gradient on rock-salt Li1.3Nb0.3Mn0.4O2 single crystals transforming through a second-order reaction and reveal the dominating effect of local chemistry on Li diffusion within the percolated network. By using advanced 2D and 3D nanoscale X-ray spectro-microscopy on well-formed crystal samples, our study visualizes the mesoscale chemical distribution as a function of the state of charge at the subparticle level. We further reveal the presence of thermodynamically favorable short-range ordering of Nb-cation-only (Nb6) and Nb-cation-enriched (MnNb5) configurations, which promote non-equilibrium diffusion pathways and the expansive chemical heterogeneity observed on LixNb0.3Mn0.4O2 particles. The present study utilizes large single crystals to eliminate the influence of kinetic factors such as particle-size distribution, crystal facet, grain boundary, and strain, allowing us to clearly demonstrate the strong correlation between a material's structural defects and chemical propagation and its crucial impact on electrode performance and stability.

BT - Chem DA - 09/2018 DO - 10.1016/j.chempr.2018.05.008 IS - 9 LA - eng N2 -

We report the observation of persistent chemical gradient on rock-salt Li1.3Nb0.3Mn0.4O2 single crystals transforming through a second-order reaction and reveal the dominating effect of local chemistry on Li diffusion within the percolated network. By using advanced 2D and 3D nanoscale X-ray spectro-microscopy on well-formed crystal samples, our study visualizes the mesoscale chemical distribution as a function of the state of charge at the subparticle level. We further reveal the presence of thermodynamically favorable short-range ordering of Nb-cation-only (Nb6) and Nb-cation-enriched (MnNb5) configurations, which promote non-equilibrium diffusion pathways and the expansive chemical heterogeneity observed on LixNb0.3Mn0.4O2 particles. The present study utilizes large single crystals to eliminate the influence of kinetic factors such as particle-size distribution, crystal facet, grain boundary, and strain, allowing us to clearly demonstrate the strong correlation between a material's structural defects and chemical propagation and its crucial impact on electrode performance and stability.

PY - 2018 SP - 2108 EP - 2123 ST - Chem T2 - Chem TI - Understanding the Effect of Local Short-Range Ordering on Lithium Diffusion in Li1.3Nb0.3Mn0.4O2 Single-Crystal Cathode VL - 4 SN - 24519294 ER -