Visualization of lithium-ion transport and phase evolution within and between manganese oxide nanorods

Abstract

Multiple lithium-ion transport pathways and local phase changes upon lithiation in silver hollandite are revealed via in situ microscopy including electron diffraction, imaging and spectroscopy, coupled with density functional theory and phase field calculations. We report unexpected inter-nanorod lithium-ion transport, where the reaction fronts and kinetics are maintained within the neighbouring nanorod. Notably, this is the first time-resolved visualization of lithium-ion transport within and between individual nanorods, where the impact of oxygen deficiencies is delineated. Initially, fast lithium-ion transport is observed along the long axis with small net volume change, resulting in two lithiated silver hollandite phases distinguishable by orthorhombic distortion. Subsequently, a slower reaction front is observed, with formation of polyphase lithiated silver hollandite and face-centred-cubic silver metal with substantial volume expansion. These results indicate lithium-ion transport is not confined within a single nanorod and may provide a paradigm shift for one-dimensional tunnelled materials, particularly towards achieving high-rate capability.

Ordering Heterogeneity of [MnO6] Octahedra in Tunnel-Structured MnO2 and Its Influence on Ion Storage

“…Mapping results show that Na ions that initially accumulated near the surface gradually diffused into the whole body of the nanorod, resulting in the uniform distribution of Na + ions in location 3. The significant change of sodium distribution in location 3 should be attributed to the large concentration gradient of Na + ions in this region, where Na + ions from their adjacent source are driven to diffuse into any open tunnel structures in a violent mode through either intra-tunnel diffusion 31 or inter-tunnel diffusion 32 as reported previously.…”

In situ interface engineering for probing the limit of quantum dot photovoltaic devices

“…In this context, the development of in situ TEM techniques enables the fabrication of in situ constructed devices in a 'nanolab' inside a TEM 20 . The state-of-the-art microscopic techniques have the unique capability to study the underlying mechanism of energy devices during operation and are employed to elucidate the charge transfer and microstructure evolution during the operation of lithium-ion batteries 21 and resistive memories 22 . In these experiments, the nanolab consists of a high-performance TEM scanning tunnelling microscopy (STM) sample holder, which allows the direct visualization of the operation of nanoscale devices mounted on it.…”

Temperature‐dependent electrical transport behavior and structural evolution in hollandite‐type titanium‐based oxide

“…[1][2][3][4][5][6] Among the numerous hollandites, titaniumbased materials have attracted considerable attention due to their improved light scattering properties, chemical stability, biological inertness, ion exchangeability, and good ionic conduction, 7,8 enabling the development of a series of new functional ceramic materials. [1][2][3][4][5][6] Among the numerous hollandites, titaniumbased materials have attracted considerable attention due to their improved light scattering properties, chemical stability, biological inertness, ion exchangeability, and good ionic conduction, 7,8 enabling the development of a series of new functional ceramic materials.…”

“…Hollandites belong to a well-known family of materials with many potential applications in energy, environment and catalysis fields. [1][2][3][4][5][6] Among the numerous hollandites, titaniumbased materials have attracted considerable attention due to their improved light scattering properties, chemical stability, biological inertness, ion exchangeability, and good ionic conduction, 7,8 enabling the development of a series of new functional ceramic materials. [9][10][11][12][13] In addition to the use of solid matrices for the immobilization of radioactive cesium and anode materials for lithium-ion batteries, [14][15][16][17] hollandite K x Ti 8 O 16 with large (2 × 2) tunnels could accommodate a large number of sodium ions and facilitate Na + diffusion in sodium ion batteries.…”