Phase transformation induced fatigue of a Ce-TZP/Al2O3 composite

In this study, the stress–cycle number (S–N curve) of a composite consisting of ceria-stabilized zirconia (Ce-TZP) and alumina (Al₂O₃) was measured. First, the initial bending strength of the Ce-TZP/Al₂O₃ composite was determined using a four-point bending technique. Next, stress above 70% of the initial bending strength was applied on the composite for up to 1,000,000 cycles. Transformation bands were formed on the tensile surface in the first several cycles as the stress was higher than a critical value. The number and width of bands then changed marginally after their fomraiton. Fatigue failure occured at the band with the largest width, as a result of slow crack growth process. The transformation bands could be removed using a post-fatigue heating treatment. After removal of these bands, the strength was consequently enhanced.     

Metallic Metastable Hybrid 1T′/1T Phase Triggered Co,P?SnS2 Nanosheets for High Efficiency Trifunctional Electrocatalyst

The development of trifunctional electrocatalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) with deeply understanding the mechanism to enhance the electrochemical performance is still a challenging task. In this work, the distorted metastable hybrid-phase induced 1T′/1T Co,P SnS₂ nanosheets on carbon cloth (1T′/1T Co,P SnS₂@CC) is prepared and examined. The density functional theoretical (DFT) calculation suggests that the distorted 1T′/1T Co,P SnS₂ can provide excellent conductivity and strong hydrogen adsorption ability. The electronic structure tuning and enhancement mechanism of electrochemical performance are investigated and discussed. The optimal 1T′/1T Co,P SnS₂@CC catalyst exhibits low overpotential of ≈94 and 219.7 mV at 10 mA cm⁻² for HER and OER, respectively. Remarkably, the catalyst exhibits exceptional ORR activity with small onset potential value (≈0.94 V) and half-wave potential (≈0.87 V). Most significantly, the 1T′/1T Co,P SnS₂||Co,P SnS₂ electrolyzer required small cell voltages of ≈1.53, 1.70, and 1.82 V at 10, 100, and 400 mA cm⁻², respectively, which are better than those of state-of-the-art Pt-C||RuO₂ (≈1.56 and 1.84 V at 10 and 100 mA cm⁻²). The present study suggests a new approach for the preparation of large-scalable, high performance hierarchical 3D next-generation trifunctional electrocatalysts.     

Formulation lyotropic liquid crystals from palm oil-based monoacylglycerols

Lyotropic liquid crystals (LLCs) made of monoacylglycerols (MAGs) are rich in potential for food and pharmaceutical applications but the understandings of these materials are quite limited. This study, therefore, precisely demonstrated the formation of some LLCs based on the combination of two palm oil-based MAGs (distilled and non-distilled) with water and a triblock copolymer (Pluronic F127). X-ray diffraction results showed that the main lyotropic mesophase obtained from palm oil-based MAGs was lamellar phase (L_α) while dynamic light scattering results revealed that these LLC particles had a size range from 0.5 to 4 μm (after 5 min homogenization at 12,000 rpm). LLC dispersions made of both palm oil-based MAGs/water mixtures were shear-thinning fluids and the sample owning a higher concentration of MAGs had a higher yield stress as well as a higher storage modulus.     

Electrochemical Self-Healing Nanocrystal Electrodes for Ultrastable Potassium-Ion Storage

The unique properties of self-healing materials hold great potential in battery systems, which can exhibit excellent deformability and return to its original shape after cycling. Herein, a Cu₃BiS₃ anode material with self-healing mechanisms is proposed for use in ultrastable potassium-ion battery (PIB) and potassium-ion hybrid capacitor (PIHC). Different from the binder design, Cu₃BiS₃ anode can exhibit the dual advantages of phase and morphological reversibility, further remaining original property after potassiation/depotassiation and exhibiting ultrastable cycling performance. The reversible electrochemical reconstruction during the continuous charge/discharge processes is beneficial to maintain the structure and function of the material. Furthermore, the conversion reactions during the charge and discharge process produce two advantages: i) suppressing the shuttle effect due to the formation of the heterostructure interface between Cu (111) and Bi (012); ii) Cu can avoid the agglomeration of Bi nanoparticles (NPs), further improving the electrochemical performance and long-cycle stability of the Cu₃BiS₃ electrode. As a result, the Cu₃BiS₃ electrode not only exhibits a long cycle life in half cells, but also 2000 cycles and 12000 cycles in PIB and PIHC full cells, respectively.     

Bonding microwave absorbing ferrites to thermal conducting copper

In the present study, the thermal characteristics of spinel ferrites are reported. The thermal expansion coefficient of ferrites is slightly larger than that of silicon; furthermore, these ferrites all demonstrate capability to absorb microwave. Nevertheless, their thermal conductivity is relatively low. A copper plate is bonded to ferrite to provide a backing for heat spreading. Microstructure observation at the interface reveals no reaction phase. The thermal resistance at the copper-ferrite interface is low. With the bonding of metallic copper, the heat generated in ferrites by microwave absorbing is possible to be removed by the backing copper layer.     

Engineering Route for Stretchable, 3D Microarchitectures of Wide Bandgap Semiconductors for Biomedical Applications

Wide bandgap (WBG) semiconductors have attracted significant research interest for the development of a broad range of flexible electronic applications, including wearable sensors, soft logical circuits, and long-term implanted neuromodulators. Conventionally, these materials are grown on standard silicon substrates, and then transferred onto soft polymers using mechanical stamping processes. This technique can retain the excellent electrical properties of wide bandgap materials after transfer and enables flexibility; however, most devices are constrained by 2D configurations that exhibit limited mechanical stretchability and morphologies compared with 3D biological systems. Herein, a stamping-free micromachining process is presented to realize, for the first time, 3D flexible and stretchable wide bandgap electronics. The approach applies photolithography on both sides of free-standing nanomembranes, which enables the formation of flexible architectures directly on standard silicon wafers to tailor the optical transparency and mechanical properties of the material. Subsequent detachment of the flexible devices from the support substrate and controlled mechanical buckling transforms the 2D precursors of wide band gap semiconductors into complex 3D mesoscale structures. The ability to fabricate wide band gap materials with 3D architectures that offer device-level stretchability combined with their multi-modal sensing capability will greatly facilitate the establishment of advanced 3D bio-electronics interfaces.