Equilibrium phase diagram of ruthenium–zirconium oxide (Ru–Zr–O) was calculated by a combination of ab initio density functional theory and thermodynamic calculations. The phase diagrams suggest that the solubility between ruthenium oxide and zirconium oxide is very low under normal experimental conditions, in good agreement with the prior reports in literature. Also provided is the theoretical support for the reported phenomenon that doping or amorphization of Ru–Zr–O might suppress phase separation of the oxide. To study the spinodal decomposition of Ru–Zr–O, we successfully prepared an amorphous Ru0.48Zr0.52O2 film of a solid solution phase by a thermal decomposition at a low temperature (563 K). In situ transmission electron microscopy was utilized to witness the spinodal decomposition of the amorphous Ru0.48Zr0.52O2 solid solution by electron–beam annealing. The present fundamental study of the phase behavior of Ru–Zr–O provides a guideline for the phase and microstructure design of Ru-based mixed oxides for various important applications.

First-principles calculations were employed to study the effects of the addition of ZrO 2 on the electrochemical activity and structure of Ir-Zr binary oxide. In the computation model employed, Zr atoms replaced Ir atoms in IrO 2 supercells, so as to form a rutile-type solid solution of Ir 1 -x Zr x O 2 (0 ≤ x ≤ 1). IrO 2 -ZrO 2 oxide coatings were prepared on Ti substrates by thermal decomposition. X-ray diffraction (XRD) analyses, cyclic voltammetry, and galvanostatic charge/discharge tests were performed to investigate the effects of the Zr content on the structure and capacitive performance of the synthesized Ti/IrO 2 -ZrO 2 electrodes. As the Zr content was increased, the density of state of Ir 1 -x Zr x O 2 moved to a higher energy level, and a forbidden band was formed, which reduced its electronic conductivity. The XRD analyses showed that ZrO 2 restrained the crystallization of IrO 2 . Thus, the extent of the amorphous phase increased with the increase in the ZrO 2 content, indicating that the proton conductivity of the binary oxide coating increased with the ZrO 2 content. When the ZrO 2 content was higher than 50 mol%, the IrO 2 -ZrO 2 coating exhibited a relatively narrow energy band gap (0.42eV) and a "amorphous/ crystalline" structure, as well as the highest charge capability, indicating that its electronic and protonic conductivities had reached an equilibrium. This was in accordance with the sudden variation in the length of the M-O bond and the change in the bulk modulus.

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Currently, stretchable hydrogel has attracted great attention in the field of wearable flexible sensors. However, fabricating flexible hydrogel sensor simultaneously with superstretchability, high mechanical strength, remarkable self-healing ability, excellent anti-freezing and sensing features via a facile method remains a huge challenge. Herein, a fully physically linked poly(hydroxyethyl acrylamide)-gelatin-glycerol-lithium chloride (PHEAA-GE-Gl-LiCl) double network organohydrogel is prepared via a simple one-pot heating-cooling-photopolymerization method. The prepared PHEAA-GE-Gl-LiCl organohydrogel exhibits favorable stretchability (970%) and remarkable self-healing property. Meanwhile, due to the presence of glycerol and LiCl, the PHEAA-GE-Gl-LiCl organohydrogel possesses outstanding anti-freezing capability, it can maintain excellent stretchability (608%) and conductivity (0.102 S/m) even at −40°C. In addition, the PHEAA-GE-Gl-LiCl organohydrogel-based strain sensor is capable of repeatedly and stably detecting and monitoring both large-scale human motions and subtle physiological signals in a wide temperature range (from −40°C to 25°C). More importantly, the PHEAA-GE-Gl-LiCl organohydrogel-based sensor displays excellent strain sensitivity (GF = 13.16 at 500% strain), fast response time (300 ms), and outstanding repeatability. Based on these super characteristics, it is envisioned that PHEAA-GE-Gl-LiCl organohydrogel holds promising potentials as wearable strain sensor.

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