Search

Most of the optical behaviors in photoelectric multifunctional ceramics strongly depend on the addition of rare‐earth elements. However, the limited species of rare‐earth cations available as luminescence centers restrict the further development of photoelectric devices. Additionally, introducing the large atomic‐radii elements usually dramatically deteriorates the piezoelectric properties. Herein, the novel photochromism and luminescence modulation properties have been realized in CuO‐doped [(K0.43Na0.57)0.94Li0.06][(Nb0.94Sb0.06)0.95Ta0.05]O3 (KNLNST) piezoelectric ceramics which show intense sensitivity to visible‐light irradiation. As a strategy for regulating oxygen vacancy concentrations in piezoelectric ceramics, different CuO amounts are doped to generate color centers for photochromism. The photoluminescence phenomenon exhibiting green emission under 375 nm excitation is observed in KNLNST piezoelectric ceramics, which is most commonly realized via rare‐earth doping in luminescent materials. KNLNST–0.3CuO ceramics with the highest oxygen vacancy concentration achieve a reversible luminescence modulation of 46.9% by altering light irradiation and thermal stimulus. Moreover, a hand‐rewritable optical information test demonstrates exceptional reproducibility and fatigue durability. This research displays the controllable photochromism and luminescence behaviors in ceramics via regulating oxygen vacancy concentration by CuO "hard" doping. The lead‐free high performance photoelectric ceramics fulfill the demands of potential applications in anti‐counterfeiting and optical storage devices. [ABSTRACT FROM AUTHOR]

BiCuSeO is a promising oxygen‐containing thermoelectric material due to its intrinsically low lattice thermal conductivity and excellent service stability. However, the low electrical conductivity limits its thermoelectric performance. Aliovalent element doping can significantly improve their carrier concentration, but it may also impact carrier mobility and thermal transport properties. Considering the influence of graphene on carrier‐phonon decoupling, Bi0.88Pb0.06Ca0.06CuSeO (BPCCSO)‐graphene composites are designed. For further practical application, a rapid preparation method is employed, taking less than 1 h, which combines self‐propagating high‐temperature synthesis with spark plasma sintering. The incorporation of graphene simultaneously optimizes the electrical properties and thermal conductivity, yielding a high ratio of weighted mobility to lattice thermal conductivity (144 at 300 K and 95 at 923 K). Ultimately, BPCCSO‐graphene composites achieve exceptional thermoelectric performance with a ZT value of 1.6 at 923 K, bringing a ≈40% improvement over BPCCSO without graphene. This work further promotes the practical application of BiCuSeO‐based materials and this facile and effective strategy can also be extended to other thermoelectric systems. [ABSTRACT FROM AUTHOR]

Potassium sodium niobate (KNN)‐based piezoelectric ceramics have emerged as a promising alternative to lead‐based systems due to their exceptional properties. While extensive research has focused on improving the electrical properties of KNN‐based ceramics through doping and processing optimization, the concurrent investigation of their mechanical properties has been lacking. This study presents a comprehensive analysis of the mechanical and electrical properties of KNN‐based lead‐free piezoceramics doped with various transition metal oxides and rare earth oxides, based on substantial experimental data. Our findings reveal that the as‐sintered KNN‐based ceramics exhibit not only outstanding electrical properties but also remarkable mechanical robustness compared to conventional toughened lead zirconate titanate (PZT)‐based ceramics. These exceptional electrical and mechanical properties are attributed to the micro‐scale and atomic‐scale structure of the modified KNN‐based ceramics, characterized by a highly condensed structure, an inhomogeneous distribution of nano‐domain structure, and the presence of amorphous intergranular films at grain boundaries. [ABSTRACT FROM AUTHOR]

Memristors are a candidate device for artificial neural systems due to their excellent conductance‐regulation ability and potential to simulate the characteristics of biological synapses. This study fabricated a Pt/TaOx/TiOy/Ti analog artificial synapse memristor that exhibits excellent multilevel storage property with a large on/off ratio of ≈660 times. The dynamic resistive switching mechanism is well expounded and validated by the reset stopping voltage dependent Schottky fitting results. Moreover, the essential biological synaptic characteristics such as long‐term potentiation/depression (LTP/D) and paired‐pulse facilitation (PPF) are successfully mimicked with a low pulse energy consumption of 12.69 nJ. A neuromorphic network constructed on the enhanced symmetry and linearity of conductance for this Pt/TaOx/TiOy/Ti memristive device can achieve 92.45% accuracy in recognizing handwritten pattern. These results demonstrate a significant potential for application Pt/TaOx/TiOy/Ti memristor in non‐volatile memory and bioinspired neuromorphic systems. [ABSTRACT FROM AUTHOR]

The development of a multi‐functional solar‐driven interfacial evaporation (SDIE) system remains a significant challenge for its large‐scale applications. By taking advantage of high surface area, excellent young's moduli, anchoring/coupling capability, large absorption surface, strong absorption in the broadband solar spectrum, and efficient photothermal conversion efficiencies of 2D emerging materials (Xenes, Mxenes, etc.), hybrid SDIEs are developed to increase the use of solar energy beyond water production. This work aims to offer a systematic review of the recent advancement in 2D emerging materials except for graphene and their significant role in hybrid SDIEs to stimulate both fundamental and applied research on utilizing the underutilized auxiliary energy sources for future integrated water, energy, and environmental systems. For this purpose, first, the most recent progress in 2D photothermal materials is discussed, mainly including emerging Xenes, MXenes, and TMDs‐inspired hybrid SDIEs. Second, structural optimization strategies and modulation of the intrinsic photothermal performances of 2D emerging materials are highlighted. Third, the cutting‐edge conceptual designs developed in many hybrid applications such as thermoelectricity, salt recovery, and hydrogen production are broadly presented. Lastly, the current challenges and perspectives of 2D emerging materials and their hybrid evaporation structures are also mentioned. [ABSTRACT FROM AUTHOR]

Solar evaporation is a facile and promising technology to efficiently utilize renewable energy for freshwater production and seawater desalination. Here, the fabrication of self‐regenerating hydrogel composed of 2D‐MXenes nanosheets embedded in perovskite La 0.6Sr 0.4Co 0.2Fe 0.8O3−δ (LSCF)/polyvinyl alcohol hydrogels for efficient solar‐driven evaporation and seawater desalination is reported. The mixed dimensional LSCF/Ti3C2 composite features a localized surface plasmonic resonance effect in the polymeric network of polyvinyl alcohol endows excellent evaporation rates (1.98 kg m−2 h−1) under 1 k Wm−2 or one sun solar irradiation ascribed by hydrophilicity and broadband solar absorption (96%). Furthermore, the long‐term performance reveals smooth mass change (13.33 kg m−2) during 8 h under one sun. The composite hydrogel prompts the dilution of concentrated brines and redissolves it back to water (1.2 g NaCl/270 min) without impeding the evaporation rate without any salt‐accumulation. The present research offers a substantial opportunity for solar‐driven evaporation without any salt accumulation in real‐life applications. [ABSTRACT FROM AUTHOR]

Marxist philosophy has always been attached to the practice. In the new age, Marxist philosophy needs to solve many problems, such as ecological destruction, environmental pollution, international conflicts, and technical innovation, and improve the integration of the Marxist philosophy system with China's national conditions. The premise of change is practice, and the premise of practice is dissemination. Promoting the dissemination of Marxist philosophy is the cornerstone of solving the blind spot in the process of Marxist philosophy popularization. Because of the development of Internet technology, in order to ensure the validity of the uploaded videos related to Marxist philosophy on the platform, combining the research on human visual perception and the advantages of the long-term recurrent convolutional network (LRCN) model in video content recognition, an attention mechanism-based LRCN model is proposed, which simulates the attention characteristics of the human brain in the deep learning model, considers the video content globally, and makes the attention of the model fall in the effective area of the whole video. The experiment uses HMDB51, UCF101, and YouTube-8M data sets, and the results show that the LRCN model based on the attention mechanism proposed in this paper can effectively improve the accuracy of video content recognition, and it can converge quickly during training to improve the efficiency of model training. [ABSTRACT FROM AUTHOR]

[(K0.43Na0.57)0.94Li0.06][(Nb0.94Sb0.06)0.95Ta0.05]O3 + x mol% Fe2O3 (KNLNST + x Fe, x = 0~0.60) lead-free piezoelectric ceramics were prepared by conventional solid-state reaction processing. The effects of small-amount Fe2O3 doping on the microstructure and electrical properties of the KNLNST ceramics were systematically investigated. With increasing Fe3+ content, the orthorhombic-tetragonal polymorphic phase transition temperature (TO-T) of KNLNST + x Fe ceramics presented an obvious "V" type variation trend, and TO-T was successfully shifted to near room temperature without changing TC (TC = 315°C) via doping Fe2O3 around 0.25 mol%. Electrical properties were significantly enhanced due to the coexistence of both orthorhombic and tetragonal ferroelectric phases at room temperature. The ceramics doped with 0.20 mol% Fe2O3 possessed optimal piezoelectric and dielectric properties of d33 = 306 pC/N, kp = 47.0%, ε33T/ε0 = 1483 and tan δ = 0.023. It was revealed that the strong internal stress in the KNLNST + x Fe ceramics with higher Fe3+ contents (x = 0.40, 0.60) stabilized the orthorhombic phase, leading to the irregular "V" type rather than the usually observed monotonic phase transition with composition change in the ceramics. [ABSTRACT FROM AUTHOR]

The ambitious pursuit of carbon neutrality underscores the pressing demand for closed‐loop recycling of lithium‐ion batteries (LIBs), amid escalating production and disposal challenges. Direct battery material recycling, emphasizing the rejuvenation of degraded materials, stands out as an environmentally benign alternative to conventional pyro‐ and hydro‐metallurgical processes that are intrinsically destructive. In addition, given the surface, interface, and interphase as the major failure mechanisms in degraded materials, rapid heating technology (RHT) emerges as a promising direct recycling method, harnessing its distinctive kinetics and thermodynamics to trigger highly time‐ and energy‐efficient, precisely defect‐ and interface‐targeted approach to revitalize degraded materials. This review summarizes recent advancements in RHT‐based LIB recycling strategies, focusing on active materials recovery, efficient regeneration, and reutilization, with emphasis on expedited kinetics and locally confined chemical reactions at interfaces. It also outlines the perspectives and future directions by emphasizing the need for re‐manufactured materials to meet increasing application demands. This comprehensive review aims to guide the recycling and upcycling of spent LIBs toward a green and sustainable battery economy. [ABSTRACT FROM AUTHOR]

Dielectric capacitors have garnered significant attention for their promising attributes in advanced pulse power systems of the future, owing to their rapid charge/discharge capabilities, high power density, and remarkable stability. Whereas environmentally friendly lead‐free ceramics are facing serious challenges of low breakdown strength, poor energy storage density, and/or conversion efficiency, which has been an obstacle to developing desirable dielectric capacitors. In this study, high‐quality ultrathin (<20 µm) lead‐free ceramic dielectrics are successfully produced via the tape‐casting method. The local structural characteristics of these ceramics are verified using piezoresponse force microscopy and aberration‐corrected scanning transmission electron microscopy. By introducing Ta5+ ions into Bi0.39Na0.36Sr0.25TiO3 ceramics, the polar clusters tend to decrease together while the maximum applied electric field tends to increase. This phenomenon can be attributed to the decreased grain size and complex polar structure characterized by extremely small polar clusters, enabling the simultaneous achievement of high applied electric field, large polarization, and minimized polarization hysteresis. Notably, the tape‐casted lead‐free ceramics exhibited exceptional comprehensive energy storage performance with a recoverable energy storage density of ≈10.06 J cm−3 and an efficiency of ≈93% under a high electric field of 915 kV cm−1, surpassing the capabilities of most reported lead‐free ceramics. This work offers a viable solution for developing lead‐free ceramic dielectrics with outstanding energy storage capabilities. [ABSTRACT FROM AUTHOR]