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In the swiftly progressing landscape of wearable electronics and the Internet of Things (IoTs), there is a burgeoning demand for devices that are lightweight, cost‐effective, and self‐powered. In this study, a self‐powered bidirectional knee joint motion monitoring system is introduced, leveraging a dual ratchet sensing (DRS) system fabricated using 3D printing technology. This approach offers substantial economic and portability benefits. The DRS system is engineered to harness the negative work generated from knee joint movements to power commercial electronic devices, obviating the need for additional metabolic energy from the human body. By synergizing the DRS with virtual reality technology, it becomes feasible to monitor knee joint movements in real‐time with remarkable accuracy, presenting a novel avenue for the integration of digital twin technology. Through the amalgamation of convolutional neural network machine learning algorithms with Bayesian optimization techniques, the DRS system can discern up to 97% of knee joint movements, paving the way for innovative applications in smart rehabilitation and healthcare. [ABSTRACT FROM AUTHOR]

Flow batteries (FBs) are one of the most promising strategies for large‐scale energy storage, in which the flow rates of electrolytes are critical to the redox reaction efficiency. However, low‐power and energy‐efficient strategies to effectively monitor and adjust the flow rates of FBs are great challenges. Here, a liquid metal based thin‐film and self‐powered triboelectric sensor (LM‐TS) to monitor and adjust the real‐time electrolyte flow rates in FBs is developed. By integrating the LM‐TS with a peristaltic pump (flow rate control unit in FB), the flow rates of electrolytes can be converted into readable electrical output signals. Furthermore, a logical and a control module are adopted to adjust the flow rates of electrolytes automatically after receiving those electrical signals, which are available to guarantee the optimal working condition of FBs. Benefiting from the high conductivity and outstanding ductility of ultrathin LM film, the self‐powered LM‐TS is endowed with high sensitivity, short response time (9.1 ms), and remarkable cyclic stability (> 20000 cycles) without affecting the normal operation of FBs. This is the first prototype of self‐powered adjustment sensor for FBs, which is readily extended to scaled‐up FB equipment for intermediate trial and large‐scale energy‐storage demonstration. [ABSTRACT FROM AUTHOR]

Piezotronic and plasmonic effects are effective strategies to improve photocatalytic performance. Combining these two effects in one photocatalytic heterostructure is intriguing, but has yet to be reported. Here, a hybrid ternary structure ((silver‐silver sulfide)/barium titanate (Ag‐Ag2S)/BaTiO3) is introduced, where the synergistic exciton–plasmon interaction in Ag‐Ag2S and Ag2S/BaTiO3 heterojunction tuned by piezoelectric polarization can enhance the photon absorption and charge carrier separation to promote photocatalysis efficiency. The exciton–plasmon interaction in Ag‐Ag2S can amplify the plasmon resonance to the semiconductor region and enhance the light absorption of Ag2S. The piezoelectric polarization can tune the band structure of BaTiO3 and then change the heterojunction between Ag2S/BaTiO3 from Type I (i.e., straddling energy band alignments between BaTiO3 and Ag2S) to Type II (i.e., Z‐scheme system between BaTiO3 and Ag2S with a staggered energy band alignment), which can accelerate the separation of electron‐hole pairs. Using this hybrid material, a high methyl orange (MO) degradation rate up to 90% within 30 min is obtained, which is 20% higher than that of Ag/BaTiO3. The demonstrated hybrid material based on the synergistic piezotronic effect and exciton–plasmon interaction shows great promise in pollutant treatment with high efficiency. [ABSTRACT FROM AUTHOR]

Ion exchange membranes play a key role in all vanadium redox flow batteries (VRFBs). The mostly available commercial membrane for VRFBs is Nafion. However, its disadvantages, such as high cost and severe vanadium‐ion permeation, become obstacles for large‐scale energy storage. It is thus crucial to develop an efficient membrane with low permeability of vanadium ions and low cost to promote commercial applications of VRFBs. In this study, graphene oxide (GO) has been employed as an additive to the Nafion 212 matrix and a composite membrane named rN212/GO obtained. The thickness of rN212/GO has been reduced to only 41 μm (compared with 50 μm Nafion 212), which indicates directly lower cost. Meanwhile, rN212/GO shows lower permeability of vanadium ions and area‐specific resistance compared to the Nafion 212 membrane due to the abundant oxygen‐containing functional groups of GO additives. The VRFB cells with the rN212/GO membrane show higher Coulombic efficiencies and lower capacity decay than those of VRFB cells with the Nafion 212 membrane. Therefore, the cost‐effective rN212/GO composite membrane is a promising alternative to suppress migration of vanadium ions across the membrane to set up VRFB cells with better performances. [ABSTRACT FROM AUTHOR]