Tim B. Eldred

Abstract: H2W2O7, a metastable material synthesized via selective etching of the Aurivillius‐related Bi2W2O9, is demonstrated as an electrode for high power proton‐based energy storage. Comprehensive structural characterization is performed to obtain a high‐fidelity crystal structure of H2W2O7 using an iterative approach that combines X‐ray diffraction, neutron pair distribution function, scanning transmission electron microscopy, Raman spectroscopy, and density functional theory modeling. Electrochemical characterization shows a capacity retention of ≈80% at 1000 mV s–1 (1.5‐s charge/discharge time) as compared to 1 mV s–1 (≈16‐min charge/discharge time) with cyclability for over 100 000 cycles. Energetics from density functional theory calculations indicate that proton storage occurs at the terminal oxygen sites within the hydrated interlayer. Last, optical micrographs collected during in situ Raman spectroscopy show reversible, multicolor electrochromism, with color changes from pale yellow to blue, purple, and last, orange as a function of proton content. These results highlight the use of selective etching of layered perovskites for the synthesis of metastable transition metal oxide materials and the use of H2W2O7 as an anode material for proton‐based energy storage or electrochromic applications.

TL;DR: In this paper , the anomalous Hall effect in pristine Cr2Te3 thin films manifests a unique temperature-dependent sign reversal at nonzero magnetization, resulting from the momentum-space Berry curvature as established by first-principles simulations.

TL;DR: In this paper , the entire formation process of a high-entropy fluorite oxide from a polymeric precursor using atomic resolution in situ gas-phase scanning transmission electron microscopy was analyzed.

TL;DR: In this paper, a transient surface morphology is introduced during dislocation mediated spiral growth, which, in conjunction with process supersaturation, determines the Ga incorporation, providing insights into compositional pulling in high Ga content AlxGa1−xN grown on AlN and providing a route to grow thicker wells with very abrupt interfaces on native AlN substrates.