Lead-free (K,Na)NbO₃ (KNN) ceramics are eco-friendly and have a high Curie temperature. In this work, high-performance KNN ceramics were synthesized through the texturing method while simplifying the components. The results indicate that the KNN-3 textured ceramics exhibit excellent piezoelectric properties of d₃₃ = 315 pC/N, d₃₃* = 600 pm/V, and k_p = 0.74 without sacrificing the Curie temperature of 394 °C. Compared with those of the KNN ceramics prepared via the conventional solid-state reaction method (d₃₃ = 104 pC/N, k_p = 0.26), d₃₃ and k_p increase by approximately 203% and 185%, respectively. Such high d₃₃ and k_p values arise from a high texture degree (f) of 94%. Additionally, at 25 °C under an electric field of 35 kV/cm, the KNN-3 ceramic shows a maximum polarization (P_max) of 28.52 μC/cm² and a remanent polarization (P_r) of 25.69 μC/cm². At 120 °C under an applied field of 30 kV/cm, the ceramic also exhibited the strain (S) = 0.18% and strain hysteresis (H) ≈ 11.1%, demonstrating excellent ferroelectric properties. Moreover, the ceramic has a high density, good breakdown strength, and low dielectric loss.

Metal oxides exhibit remarkable gas sensing effect and adjustable physicochemical properties, making them widely utilized in chemiresistive gas sensors. The aggregation of metal oxide nanostructures, however, results in a reduction of specific surface area and porosity, thereby affecting the gas sensing properties. The primary challenge involves effectively addressing the deficiencies in surface adsorption and electron transfer capabilities. In this study, we developed a solvothermal template approach for the synthesis of zero-dimensional/two-dimensional nanosheets, enabling highly sensitive detection of ammonia at low operating temperatures. The findings illustrate that the synergistic interaction between Fe₃O₄ nanoparticles and Ti₃C₂T_x MXene nanosheets establishes an interface characterized by chemical and electronic coupling, facilitating an additional pathway for charge transfer. Simultaneously, the adsorption and sensing of ammonia molecules on Fe₃O₄/Ti₃C₂T_x MXene are thermodynamically and kinetically more favorable compared to Fe₃O₄ alone. The Fe₃O₄/Ti₃C₂T_x MXene sensor exhibits excellent sensing performance for ammonia, with high sensitivity (Ra/Rg = 5.3 at 500 ppb, where Ra represents the sensor resistance in air and Rg represents the sensor resistance in the target gas) and ultra-fast response time, while maintaining high selectivity and long-term stability. This work proposes an innovative approach for the integration of nanoparticles and MXenes, which holds great potential for advancing the development of high-performance gas sensors.

Human–machine interactions (HMIs) have advanced rapidly in recent decades in the fields of healthcare, work, and life. However, people with disabilities and other mobility problems do not have corresponding high-tech aids for them to enjoy the convenience of HMIs. In this paper, we propose a sensor with a wave-shaped (corrugated) electrode embedded in a friction layer, which exhibits high sensitivity to skin fold excitation and enormous potential in HMIs. Attributing to the wave-shaped electrode design, it has no built-in cavities, and its small size allows it to flexibly cope with folds at different angles. By specifying the carbon nanotube hybrid silicone film as the electrode layer material and silicone film as the friction layer, good electrical output performance, tensile properties, and biocompatibility can be achieved. Then, the sensor is tested on various joints and skin folds of the human body, the output signals of which can be distinguished between normal physiological behavior and test behavior. Based on this sensor, we designed a medical alarm system, a robotic arm assistive system, and a cell phone application control system for the disabled to help them in the fields of healthcare, work, and life. In conclusion, our research presents a feasible technology to enhance HMIs and makes a valuable contribution to the development of high-tech aids for the disabled.