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The ionic conductivity of composite solid-state electrolytes does not meet the application requirements of solid-state lithium (Li) metal batteries owing to the harsh space charge layer of different phases and low concentration of movable Li + . Herein, we propose a robust strategy for creating high-throughput Li + transport pathways by coupling the ceramic dielectric and electrolyte to overcome the low ionic conductivity challenge of composite solid-state electrolytes. A highly conductive and dielectric composite solid-state electrolyte is constructed by compositing the poly(vinylidene difluoride) matrix and the BaTiO 3 –Li 0.33 La 0.56 TiO 3– x nanowires with a side-by-side heterojunction structure (PVBL). The polarized dielectric BaTiO 3 greatly promotes the dissociation of Li salt to produce more movable Li + , which locally and spontaneously transfers across the interface to coupled Li 0.33 La 0.56 TiO 3– x for highly efficient transport. The BaTiO 3 –Li 0.33 La 0.56 TiO 3– x effectively restrains the formation of the space charge layer with poly(vinylidene difluoride). These coupling effects contribute to a quite high ionic conductivity (8.2 × 10 −4  S cm −1 ) and lithium transference number (0.57) of the PVBL at 25 °C. The PVBL also homogenizes the interfacial electric field with electrodes. The LiNi 0.8 Co 0.1 Mn 0.1 O 2 /PVBL/Li solid-state batteries stably cycle 1,500 times at a current density of 180 mA g − 1 , and pouch batteries also exhibit an excellent electrochemical and safety performance. The authors developed a highly conductive and dielectric composite solid-state electrolyte by coupling BaTiO 3 and Li 0.33 La 0.56 TiO 3– x nanowires with a side-by-side heterojunction structure in a polyvinylidene difluoride matrix, which simultaneously promotes the dissociation of lithium salts to produce more movable Li ions and efficiently transports the generated movable Li ions.

Lightweight flexible piezoelectric polymers are demanded for various applications. However, the low instinctively piezoelectric coefficient ( i.e . d33) and complex poling process greatly resist their applications. Herein, we show that introducing dynamic pressure during fabrication is capable for poling polyvinylidene difluoride/barium titanate (PVDF/BTO) composites with d33 of ~51.20 pC/N at low density of ~0.64 g/cm 3 . The melt-state dynamic pressure driven energy implantation induces structure evolutions of both PVDF and BTO are demonstrated as reasons for self-poling. Then, the porous material is employed as pressure sensor with a high output of ~20.0 V and sensitivity of ~132.87 mV/kPa. Besides, the energy harvesting experiment suggests power density of ~58.7 mW/m 2 can be achieved for 10 N pressure with a long-term durability. In summary, we not only provide a high performance lightweight, flexible piezoelectric polymer composite towards sustainable self-powered sensing and energy harvesting, but also pave an avenue for electrical-free fabrication of piezoelectric polymers. Lightweight flexible piezoelectric polymers are demanded for various applications, but restricted by the low instinctively piezoelectric coefficient and complex poling process. Here, the authors develop a high performance lightweight, flexible self-poled piezoelectric polymer composite towards sustainable self-powered sensing and energy harvesting.

Development of organic theranostic agents that are active in the second near-infrared (NIR-II, 1000–1700 nm) biowindow is of vital significance for treating deep-seated tumors. However, studies on organic NIR-II absorbing agents for photo-to-heat energy-converting theranostics are still rare simply because of tedious synthetic routes to construct extended π systems in the NIR-II region. Herein, we design a convenient strategy to engineer highly stable organic NIR-II absorbing theranostic nanoparticles (Nano-BFF) for effective phototheranostic applications via co-assembling first NIR (NIR-I, 650–1000 nm) absorbing boron difluoride formazanate (BFF) dye with a biocompatible polymer, endowing the Nano-BFF with remarkable theranostic performance in the NIR-II region. In vitro and in vivo investigations validate that Nano-BFF can serve as an efficient theranostic agent to achieve photoacoustic imaging guided deep-tissue photonic hyperthermia in the NIR-II biowindow, achieving dramatic inhibition toward orthotopic hepatocellular carcinoma. This work thus provides an insight into the exploration of versatile organic NIR-II absorbing nanoparticles toward future practical applications. Organic agents with activity in the second near infrared region (NIR-II) are needed for precise treatment of cancer. Here, the authors develop boron difluoride formazanate nanosystem as a theranostic agent active in the NIR-II region for treating deep-seated hepatocellular carcinoma in mice.

Demands on superhydrophobic, self-cleaning and piezoelectric membranes have gained significantly due to their potential to overcome global shortages in clean water and energy. In this study, we have discovered a novel plasma-assisted nonsolvent induced phase separation (PANIPS) method to prepare superhydrophobic, self-cleaning and piezoelectric poly(vinylidene difluoride) (PVDF) membranes without additional chemical modifications or post-treatments. The PANIPS membranes exhibit water contact angles ranging from 151.2° to 166.4° and sliding angles between 6.7° and 29.7°. They also show a high piezoelectric coefficient (d33) of 10.5 pC N −1 and can generate a high output voltage of 10 V pp . The PANIPS membranes can effectively recover pure water from various waste solutions containing Rose Bengal dye, humic acid, or sodium dodecyl sulfate via direct contact membrane distillation (DCMD). This study may provide valuable insights to fabricate PANIPS membranes and open up new avenues to molecularly design advanced superhydrophobic, self-cleaning, and piezoelectric membranes in the fields of clean water production, motion sensor, and piezoelectric nanogenerator. The structures and properties of membranes depend strongly on their preparation methods. Here, the authors present a plasma-assisted nonsolvent-induced phase separation method that allows to tailor the physicochemical and electrical characteristics of PVDF membranes for various applications.

Piezoelectric electronics possess great potential in flexible sensing and energy harvesting applications. However, they suffer from low electromechanical performance in all-organic piezoelectric systems due to the disordered and weakly-polarized interfaces. Here, we demonstrated an all-polymer piezo-ionic-electric electronics with PVDF/Nafion/PVDF (polyvinylidene difluoride) sandwich structure and regularized ion-electron interfaces. The piezoelectric effect and piezoionic effect mutually couple based on such ion-electron interfaces, endowing this electronics with the unique piezo-ionic-electric working mechanism. Further, owing to the massive interfacial accumulation of ion and electron charges, the electronics obtains a remarkable force-electric coupling enhancement. Experiments show that the electronics presents a high d 33 of ~80.70 pC N −1 , a pressure sensitivity of 51.50 mV kPa −1 and a maximum peak power of 34.66 mW m −2 . It is applicable to be a transducer to light LEDs, and a sensor to detect weak physiological signals or mechanical vibration. This work shows the piezo-ionic-electric electronics as a paradigm of highly-optimized all-polymer piezo-generators. Low electromechanical performance is a limiting factor for all-organic piezoelectric systems. Here, Xu et al. report an all-polymer piezo-ionic-electric electronics, coupling the piezoelectric effect with the piezoionic effect for enhanced performance.

The impedance mismatch of carbon materials is a key factor limiting their widespread use in electromagnetic (EM) wave absorption. In this work, the novel CeO 2 /nitrogen-doped carbon (CeO 2 /N-C) nanofiber was prepared to solve the problem by electrospinning and sintering. X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) analyses demonstrated CeO 2 was successfully loaded onto the surface of partially graphitized carbon fibers. Different sintering temperatures change the graphitization degree of material, and the oxygen vacancy structure of CeO 2 and defects from N doping optimize the impedance matching of the material. When the sintering temperature reaches 950 °C, CeO 2 /N-C fiber possesses the minimum reflection loss (RL min ) value of −42.59 dB at 2.5 mm with a filler loading of only 3 wt.% in polyvinylidene difluoride (PVDF). Meanwhile, the CeO 2 /N-C fiber achieves a surprising wideband (8.48 GHz) at a thickness of 2.5 mm, covering the whole Ku-band as well as 63% of the X-band at the sintering temperature of 650 °C. This work provides the research basis for widely commercial applications of carbon-based nanofiber absorbers.

Fluorinated small molecules are prevalent across the functional small-molecule spectrum, but the scarcity of naturally occurring sources creates an opportunity for creative endeavour in developing routes to access these important materials. Iodine(I)/iodine(III) catalysis has proven to be particularly well-suited to this task, enabling abundant alkene substrates to be readily intercepted by in situ-generated λ3-iodanes and processed to high-value (di)fluorinated products. These organocatalysis paradigms often emulate metal-based processes by engaging the π bond and, in the case of styrenes, facilitating fluorinative phenonium-ion rearrangements to generate difluoromethylene units. Here we demonstrate that enynes are competent proxies for styrenes, thereby mitigating the recurrent need for aryl substituents, and enabling highly versatile homopropargylic difluorides to be generated in an operationally simple manner. The scope of the method is disclosed, together with application in target synthesis (>30 examples, up to >90% yield).Hypervalent iodine catalysis remains a powerful method to enable geminal difluoromethylenation of alkenes. However, the scope is mainly limited to styrene derivatives. Now, enynes have been validated as competent substrates where a formal 1,2-shift of the alkyne occurs, thereby enabling highly versatile homopropargylic difluorides to be generated.

HighlightsMIL-88C (Fe) with varying aspect ratios as a precursor was synthesized by regulating oil bath conditions, followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.High-efficiency microwave absorption properties were achieved with RLmin value of -67.4 dB (2.13 mm) and wide effective absorption bandwidth (EAB) of 5.52 GHz (1.90 mm) under the low filler loading.A symmetric gradient honeycomb structure was constructed utilizing the high-frequency structure simulator, achieving an EAB of 14.6 GHz and a RLmin of -59.0 dB.The impedance matching of absorbers is a vital factor affecting their microwave absorption (MA) properties. In this work, we controllably synthesized Material of Institute Lavoisier 88C (MIL-88C) with varying aspect ratios (AR) as a precursor by regulating oil bath conditions, followed by one-step thermal decomposition to obtain carbon-coated iron-based composites. Modifying the precursor MIL-88C (Fe) preparation conditions, such as the molar ratio between metal ions and organic ligands (M/O), oil bath temperature, and oil bath time, influenced the phases, graphitization degree, and AR of the derivatives, enabling low filler loading, achieving well-matched impedance, and ensuring outstanding MA properties. The MOF-derivatives 2 (MD2)/polyvinylidene Difluoride (PVDF), MD3/PVDF, and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt% and as low as 5 wt%. The MD2/PVDF (5 wt%) achieved a maximum effective absorption bandwidth (EAB) of 5.52 GHz (1.90 mm). The MD3/PVDF (10 wt%) possessed a minimum reflection loss (RLmin) value of − 67.4 at 12.56 GHz (2.13 mm). A symmetric gradient honeycomb structure (SGHS) was constructed utilizing the high-frequency structure simulator (HFSS) to further extend the EAB, achieving an EAB of 14.6 GHz and a RLmin of − 59.0 dB. This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.

Transition-metal catalyzed allylic substitution reactions of alkenes are among the most efficient methods for synthesizing diene compounds, driven by the inherent preference for an inner-sphere mechanism. Here, we present a demonstration of an outer-sphere mechanism in Rh-catalyzed allylic substitution reaction of simple alkenes using gem -difluorinated cyclopropanes as allyl surrogates. This unconventional mechanism offers an opportunity for the fluorine recycling of gem -difluorinated cyclopropanes via C − F bond cleavage/reformation, ultimately delivering allylic carbofluorination products. The developed method tolerates a wide range of simple alkenes, providing access to secondary, tertiary fluorides and gem -difluorides with 100% atom economy. DFT calculations reveal that the C − C bond formation goes through an unusual outer-sphere nucleophilic substitution of the alkenes to the allyl-Rh species instead of migration insertion, and the generated carbon cation then forms the C − F bond with tetrafluoroborate as a fluoride shuttle. Allylic substitution reaction of alkenes has been well-developed, but it has limitations, partly due to the intrinsic predilection for an inner-sphere mechanism. Herein, the authors present an outer-sphere mechanism in Rh-catalyzed allylic substitution reaction of simple alkenes using gem-difluorinated cyclopropanes as allyl surrogates.

Fluorinated heterocycles are prevalent in Pharmaceuticals, agrochemicals, and materials. However, reactions that incorporate fluorine into heteroarenes are limited in scope and can be hazardous. We present a broadly applicable and safe method for the site-selective fluorination of a single carbon-hydrogen bond in pyridines and diazines using commercially available silver(II) fluoride. The reactions occur at ambient temperature within 1 hour with exclusive selectivity for fluorination adjacent to nitrogen. The mild conditions allow access to fluorinated derivatives of medicinally important compounds, as well as a range of 2-substituted pyridines prepared by subsequent nucleophilic displacement of fluoride. Mechanistic studies demonstrate that the pathway of a classic pyridine amination can be adapted for selective fluorination of a broad range of nitrogen heterocycles.