Toward Conductive Additive Free Organic Electrode for Lithium-Ion Battery Using Supramolecular Columnar Organization.

With the aim to meet the greatest challenge facing organic batteries, namely the low conductivity of the electrodes, the electrochemical properties of a series of substituted perylene diimides able to form semi-conductive columnar material are investigated. Depending on the substituent group, a strong influence of this group on the reversibility, redox potential but especially on the gravimetric capacity of the electrodes is observed. In the case of substitution by a simple propyl group, the corresponding diimide shows a complete electrochemical activity with only 10% by mass of conductive additive and even shows a half-capacity activity without any additive and without particular electrode engineering. Extensive research has highlighted the intrinsic reactivity of the columnar material but also its perpetual rearrangement during charge/discharge cycles. This study shows that the amount of conductive additive can be significantly reduced by adapting the design of the molecular material and favoring the assembly of redox units in the form of a conductive column.

Halogenated 9H-Indeno[1,2-b]Pyrazine-2,3-Dicarbonitrile End Groups Based Asymmetric Non-Fullerene Acceptors for Green Solvent-Processable, Additive-Free, and Stable Organic Solar Cells.

Non-fullerene acceptors (NFAs) significantly enhance photovoltaic performance in organic solar cells (OSCs) using halogenated solvents and additives. However, these solvents are environmentally detrimental and unsuitable for industrial-scale production, and the issue of OSCs' poor long-term stability persists. This report introduces eight asymmetric NFAs (IPCnF-BBO-IC2F, IPCnF-BBO-IC2Cl, IPCnCl-BBO-IC2F, and IPCnCl-BBO-IC2Cl, where n = 1 and 2). These NFAs comprise a 12,13-bis(2-butyloctyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno-[3,2-b]indole (BBO) core. One end of the core attaches to a mono- or di-halogenated 9H-indeno[1,2-b]pyrazine-2,3-dicarbonitrile (IPC) end group (IPC1F, IPC1Cl, IPC2F, or IPC2Cl), while the other end connects to a 2-(5,6-dihalo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (IC) end group (IC2F or IC2Cl). The optical and electronic properties of these NFAs can be finely tuned by controlling the number of halogen atoms. Crucially, these NFAs demonstrate excellent compatibility with PM6 even in o-xylene, facilitating the production of additive-free OSCs. The di-halogenated IPC-based NFAs outperform their mono-halogenated counterparts in photovoltaic performance within OSCs. Remarkably, the di-halogenated IPC-based NFAs maintain 94‒98% of their initial PCEs over 2000 h in air without encapsulation, indicating superior long-term device stability. These findings imply that the integration of di-halogenated IPCs in asymmetric NFA design offers a promising route to efficient, stable OSCs manufactured through environmentally friendly processes.

The Potential of Self-Activating Au(I) Complexes in Gold Catalysis.

Gold catalysis has emerged as a groundbreaking field in synthetic chemistry, revolutionizing numerous organic transformations. Despite the significant achieved advancements, the mechanistic understanding behind many gold-catalyzed reactions remains elusive. This Concept article covers the so-called "self-activating" Au(I) complexes, sorting out their pivotal role in gold catalysis. We comment on how Au(I) complexes can undergo self-activation, triggering diverse catalytic transformations without the need for external additives. The most important examples reported so far that underlie the catalytic activity of these species are discussed. This intrinsic reactivity represents a paradigm shift in gold catalysis, offering new avenues for the design of efficient and sustainable catalytic systems. Furthermore, we explore the factors influencing the stability, reactivity, and selectivity of these Au(I) complexes, providing insights into their synthetic utility and potential applications. This area of research not only advances our fundamental understanding of gold catalysis but also paves the way for the development of novel catalytic strategies with broad implications in organic synthesis and the chemical industry.

Ti3 C2 TX MXene Ink Direct Writing Flexible Sensors for Disposable Paper Toys.

Flexible electronics have gained great attention in recent years owing to their promising applications in biomedicine, sustainable energy, human-machine interaction, and toys for children. Paper mainly produced from cellulose fibers is attractive substrate for flexible electronics because it is biodegradable, foldable, tailorable, and light-weight. Inspired by daily handwriting, the rapid prototyping of sensing devices with arbitrary patterns can be achieved by directly drawing conductive inks on flat or curved paper surfaces; this provides huge freedom for children to design and integrate "do-it-yourself (DIY)" electronic toys. Herein, viscous and additive-free ink made from Ti3 C2 TX MXene sediment is employed to prepare disposable paper electronics through a simple ball pen drawing. The as-drawn paper sensors possess hierarchical microstructures with interweaving nanosheets, nanoflakes, and nanoparticles, therefore exhibiting superior mechanosensing performances to those based on single/fewer-layer MXene nanosheets. As proof-of-concept applications, several popular children's games are implemented by the MXene-based paper sensors, including "You say, I guess," "Emotional expression," "Rock-Paper-Scissors," "Arm wrestling," "Throwing game," "Carrot squat," and "Grab the cup," as well as a DIY smart whisker for a cartoon mouse. Moreover, MXene-based paper sensors are safe and disposable, free from producing any e-waste and hazard to the environment.

Binary Metallic CuCo5 S8 Anode for High Volumetric Sodium-Ion Storage.

With the rapid improvement of compact smart devices, fabricating anode materials with high volumetric capacity has gained substantial interest for future sodium-ion batteries (SIBs) applications. Herein, a novel bimetal sulfide CuCo5 S8 material is proposed with enhanced volumetric capacity due to the intrinsic metallic electronic conductivity of the material and multi-electron transfer during electrochemical procedures. Due to the intrinsic metallic behavior, the conducting additive (CA) could be removed from the electrode fabrication without scarifying the high rate capability. The CA-free CuCo5 S8 electrode can achieve a high volumetric capacity of 1436.4 mA h cm-3 at a current density of 0.2 A g-1 and 100 % capacity retention over 2000 cycles in SIBs, outperforming most metal chalcogenides, owing to the enhanced electrode density. Reversible conversion reactions are revealed by combined measurements for sodium systems. The proposed new strategy offers a viable approach for developing innovative anode materials with high-volumetric capacity.

External Catalyst- and Additive-Free Photo-Oxidation of Aromatic Alcohols to Carboxylic Acids or Ketones Using Air/O2.

We present an environment-friendly and highly efficient method for the oxidation of aromatic alcohols to carboxylic acids or ketones in air via light irradiation under external catalyst-, additive-, and base-free conditions. The photoreaction system exhibits a wide substrate scope and the potential for large-scale applications. Most of the desired products are easily obtained via recrystallization and separation from low-boiling reaction medium acetone in good yields, and the products can be subsequent directly transformed without further purification.

Amorphous Calcium Carbonate Cluster Nanospheres in Water-Deficient Organic Solvents.

As the key intermediate phase of crystalline calcium carbonate biominerals, amorphous calcium carbonate (ACC) remains mysterious in its structures because of its long-range disorder and instability. We herein report the synthesis of ACC nanospheres in a water-deficient organic solvent system. The obtained ACC nanospheres are very stable under dry conditions. Cryo-TEM reveals that each nanospheres consists of smaller nanosized clusters. We further demonstrate that these clusters can precipitate on other substrates to form an ultrathin ACC coating, which should be an ACC cluster monolayer. The results demonstrate that the presence of small ACC clusters as the subunits of larger aggregates is inherent to ACC synthesized in water-alcohol system but not induced by polymer additives.

Copper-Catalyzed Redox Coupling of Nitroarenes with Sodium Sulfinates.

A simple copper-catalyzed redox coupling of sodium sulfinates and nitroarenes is described. In this process, abundant and stable nitroarenes serve as both the nitrogen sources and oxidants, and sodium sulfinates act as both reactants and reductants. A variety of aromatic sulfonamides were obtained in moderate to good yields with broad substrate scope. No external additive is employed for this kind of transformation.

Catalyst-free synthesis of 4-acyl-NH-1,2,3-triazoles by water-mediated cycloaddition reactions of enaminones and tosyl azide.

The synthesis of 4-acyl-NH-1,2,3-triazoles has been accomplished with high efficiency through the cycloaddition reactions between N,N-dimethylenaminones and tosyl azide. This method is featured with extraordinary sustainability by employing water as the sole medium, free of any catalyst or additive, authentically mild conditions (40 °C stirring) as well as practical scalability.

Combination of Thiol-Additive-Free Native Chemical Ligation/Desulfurization and Intentional Replacement of Alanine with Cysteine.

We report a novel strategy for native chemical ligation (NCL). Alanines not located at a ligation site are temporarily replaced with cysteines, and this enables efficient thiol-additive-free NCL, with subsequent desulfurization to regenerate the target peptide. We synthesized stresscopin-related peptide and neuroendocrine regulatory peptide-2 (NERP-2) by this method. We confirmed that both conventional alkyl thioester and thioester-equivalent N-acyl-N'-methyl-benzimidazolinone (MeNbz) can be adopted as thioester components for thiol-additive-free NCL of multi-Cys-containing peptides.

Imidazole-Aided Native Chemical Ligation: Imidazole as a One-Pot Desulfurization-Amenable Non-Thiol-Type Alternative to 4-Mercaptophenylacetic Acid.

Various bioactive proteins have been synthesized by native chemical ligation (NCL) and its combination with subsequent desulfurization (e.g., conversion from Cys to Ala). In NCL, excess 4-mercaptophenylacetic acid (MPAA) is generally added to facilitate the reaction. However, co-elution of MPAA with the ligation product during preparative high-performance liquid chromatography sometimes reduces its usefulness. In addition, contamination of MPAA disturbs subsequent desulfurization. Here, we report for the first time that imidazole can be adopted as an alternative to MPAA in NCL using a peptide-alkylthioester. The efficiency of the imidazole-aided NCL (Im-NCL) is similar to that of traditional MPAA-aided NCL. As model cases, we successfully synthesized adiponectin(19-107) and [Ser(PO3 H2 )65 ]-ubiquitin using Im-NCL with a one-pot desulfurization.

Fe(III)-catalyzed stereoselective synthesis of deoxyglycosides using stable bifunctional deoxy-phenylpropiolate glycoside donors.

Herein, we report a mild and economical route for the stereoselective synthesis of 2-deoxy and 2,6-dideoxyglycosides via FeCl3-catalyzed activation of bench stable deoxy-phenylpropiolate glycosyl donors (D-PPGs). Optimized reaction conditions work well under additive-free conditions to afford the corresponding 2-deoxy and 2,6-dideoxyglycosides in good yields with high α-anomeric selectivity by reacting with sugar and non-sugar-based acceptors. The optimized conditions were also extended for disarmed D-PPG donors. In addition, the developed strategy is amenable to high-scale-up synthesis.

Electrochemically Exfoliated Graphene Additive-Free Inks for 3D Printing Customizable Monolithic Integrated Micro-Supercapacitors on a Large Scale.

Three-dimensional (3D) printing technology with enhanced fidelity can achieve multiple functionalities and boost electrochemical performance of customizable planar micro-supercapacitors (MSCs), however, precise structural control of additive-free graphene-based macro-assembly electrode for monolithic integrated MSCs (MIMSCs) remains challenging. Here, the large-scale 3D printing fabrication of customizable planar MIMSCs is reported utilizing additive-free, high-quality electrochemically exfoliated graphene inks, which is not required the conventional cryogenic assistance during the printing process and any post-processing reduction. The resulting MSCs reveal an extremely small engineering footprint of 0.025 cm2, exceptionally high areal capacitance of 4900 mF cm-2, volumetric capacitance of 195.6 F cm-3, areal energy density of 2.1 mWh cm-2, and unprecedented volumetric energy density of 23 mWh cm-3 for a single cell, surpassing most previously reported 3D printed MSCs. The 3D printed MIMSC pack is further demonstrated, with the maximum areal cell count density of 16 cell cm-2, the highest output voltage of 192.5 V and the largest output voltage per unit area of 56 V cm-2 up to date are achieved. This work presents an innovative solution for processing high-performance additive-free graphene ink and realizing the large-scale production of 3D printed MIMSCs for planar energy storage.

Additive-Free Anode with High Stability: Nb2CTx MXene Prepared by HCl-LiF Hydrothermal Etching for Lithium-Ion Batteries.

MXenes, represented by Ti3C2Tx, have been widely studied in the electrochemical energy storage fields, including lithium-ion batteries, for their unique two-dimensional structure, tunable surface chemistry, and excellent electrical conductivity. Recently, Nb2CTx, as a new type of MXene, has attracted more and more attention due to its high theoretical specific capacity of 542 mAh g-1. However, the preparation of few-layer Nb2CTx nanosheets with high-quality remains a challenge, which limits their research and application. In this work, high-quality few-layer Nb2CTx nanosheets with a large lateral size and a high conductivity of up to 500 S cm-1 were prepared by a simple HCl-LiF hydrothermal etching method, which is 2 orders of magnitude higher than that of previously reported Nb2CTx. Furthermore, from its aqueous ink, the viscosity-tunable organic few-layer Nb2CTx ink was prepared by HCl-induced flocculation and N-methyl-2-pyrrolidone treatment. When using the organic few-layer Nb2CTx ink as an additive-free anode of lithium-ion batteries, it showed excellent cycling performance with a reversible specific capacity of 524.0 mAh g-1 after 500 cycles at 0.5 A g-1 and 444.0 mAh g-1 after 5000 cycles at 1 A g-1. For rate performance, a specific capacity of 159.8 mAh g-1 was obtained at a high current density of 5 A g-1, and an excellent capacity retention rate of about 95.65% was achieved when the current density returned to 0.5 A g-1. This work presents a simple and scalable process for the preparation of high-quality Nb2CTx and its aqueous/organic ink, which demonstrates important application potential as electrodes for electrochemical energy storage devices.

High mass loading and additive-free prussian blue analogue based flexible electrodes for Na-ion supercapacitors.

Supercapacitor electrodes often suffer from the low mass loading of active substances and the unsatisfactory ion/charge transport features due to the use of various additives. Exploring high mass loading and additive-free electrodes is of huge significance to develop advanced supercapacitors with commercial application prospects, which still remains challenging. Herein, high mass loading CoFe-prussian blue analogue (CoFe-PBA) electrodes are developed by a facile co-precipitation method using activated carbon cloth (ACC) as the flexible substrate. The homogeneous nanocube structure, large specific surface area (143.9 m2 g-1) and appropriate pore size distribution (3.4 nm) of the CoFe-PBA endow the as-prepared CoFe-PBA/ACC electrodes with low resistance and appealing ion diffusion characteristics. Typically, the high areal capacitance (1155.0 mF cm-2 at 0.5 mA cm-2) is obtained for high mass loading CoFe-PBA/ACC electrodes (9.7 mg cm-2). Furthermore, symmetrical flexible supercapacitors (FSCs) are constructed using CoFe-PBA/ACC electrodes and Na2SO4/polyving alcohol (Na2SO4/PVA) gel electrolyte, achieving superior stability (85.6% capacitance retention after 5,000 cycles), maximum energy density of 33.8 µWh cm-2 at 200.0 µW cm-2 and promising mechanical flexibility. This work is expected to offer inspirations for the development of high mass loading and additive-free electrodes for FSCs.

Finely Tuned Molecular Packing Realized by a New Rhodanine-Based Acceptor Enabling Excellent Additive-Free Small- and Large-Area Organic Photovoltaic Devices Approaching 19 and 12.20% Efficiencies.

A new nonfullerene acceptor (NFA), BTA-ERh, was synthesized and integrated into a PM6:Y7:PC71BM ternary system to regulate the blend film morphology for enhanced device performance. Due to BTA-ERh's good miscibility with host active blend films, an optimized film morphology was obtained with appropriate phase separation and fine-tuning of film crystallinity, which ultimately resulted in efficient exciton dissociation, charge transport, lower recombination loss, and decreased trap-state density. The resulting additive-free quaternary devices achieved a remarkable efficiency of 18.90%, with a high voltage, fill factor, and current density of 0.87 V, 76.32%, and 28.60 mA cm-2, respectively. By adding less of a new small molecule with high crystallinity, the favorable nanomorphology shape of blend films containing NFAs might be adjusted. Consequently, this strategy can enhance photovoltaic device performance for cutting-edge NFA-based organic solar cells (OSCs). In contrast, the additive-free OSCs exhibited good operational stability. More importantly, large-area modules with the quaternary device showed a remarkable efficiency of 12.20%, with an area as high as 55 cm2 (substrate size, 100 cm2) in an air atmosphere via D-bar coating. These results highlight the enormous research potential for a multicomponent strategy for future additive-free OSC applications.

3D-printing of easily recyclable all-ceramic thick LiCoO2 electrodes with enhanced areal capacity for Li-ion batteries using a highly filled thermoplastic filament.

In this work, the production of thick ceramic LiCoO2 (LCO) electrodes using a conventional desktop 3D-printing was developed as an alternative to conventional electrode manufacturing for Li-ion batteries. Firstly, the filament formulation, based on LCO powders and a sacrificial polymers blend, is optimized to achieve suitable features (viscosity, flexibility and mechanical consistency) to be used in the 3-D printing. Printing parameters were optimized to produce defect-free bodies with coin geometry (12 mm diameter and 230-850 µm thickness). Thermal debinding and sintering were studied in order to obtain all ceramic LCO electrodes with adequate porosity. The additive-free sintered electrodes (850 µm thickness) have enhanced areal and volumetric capacities (up to 28 mA·h·cm-2 and 354 mA·h·cm-3) due to their extremely high mass loading (up to 285 mg·cm-2). Thus, the Li//LCO half-cell delivered an energy density of 1310 W·h·L-1. The ceramic nature of the electrode permits the use of a thin film of paint gold as current collector, reducing considerably the polarization of thick electrodes. Thus, the whole manufacturing process developed in this work is a complete solvent-free method to produce tuneable shape electrodes with enhanced energy density, opening the door for the manufacturing of high-density batteries with complex geometries and good recyclable.

Catalyst- and Additive-Free Methodical Ring Expansion Protocol to Access Benzooxepino-Fused Pyrroles.

An efficient metal-free, additive-free synthetic method was developed to access benzooxepino-fused pyrrole derivatives from alkynyl substituted aziridines. In this organic transformation, two new C-C bonds were formed via initial cleavage of C-C bond of aziridine ring by in situ generated azomethine ylides. Moderate to excellent yields of benzooxepino-fused pyrroles were obtained atom economically in the presence of t-BuOH in one-pot.

Green construction of metal- and additive-free citrus peel-derived carbon dot/g-C3N4 photocatalysts for the high-performance photocatalytic decomposition of sunset yellow.

In this study, novel, metal-free, CP-derived CDs/g-C3N4 nanocomposites (CDCNs) were created by introducing citrus peel-derived carbon dots (CP-derived CDs) into graphite carbon nitride (g-C3N4) by a green hydrothermal method. The CDCNs were revealed to have superior photoelectrochemical properties relative to pristine g-C3N4 for the photocatalytic degradation of the food dye sunset yellow (SY) under visible light. For SY decomposition, the recommended catalyst contributed almost 96.3% to the photodegradation rate after 60 min of irradiation, showing satisfactory reusability, structural stability and biocompatibility. Moreover, a mechanism for enhanced photocatalytic SY degradation was proposed according to band analysis, free radical trapping and electron paramagnetic resonance (EPR) results. A possible pathway for SY photodegradation was also predicted from UV-visible (UV-Vis) spectroscopy and high-performance liquid chromatography (HPLC) results. The constructed nonmetallic nanophotocatalysts afford a novel route for the elimination of harmful dyes and for the resource conversion of citrus peels.

Flexure-resistant and additive-free poly (L-lactic acid) hydrophobic membranes fabricated by slow phase separation.

PLLA membranes with excellent ductility were successfully prepared by a simple solvent evaporation-induced precipitation method, without any additive. The excellent mechanical properties are mainly attributed to the interconnecting pore morphology and the plastic deformation of the pore wall during the stretching process. The interconnecting pore morphology is determined by delaying non-solvent diffusion and molecular chain pre-nucleation. It was found that the average pore size gradually decreased from 19.25 µm to 6.71 µm as the concentration of the polymer solution increased from 0.03 g/ml to 0.10 g/ml, and the elongation at break of the membrane can reach 130.8%. The crystallinity is between 33.4% and 44.5%, and the crystal form is a perfect α crystal. Membrane with interconnecting pore structure contributes to the formation of 91.2% porosity. Furthermore, the solvent evaporation-induced precipitation method can also form surfaces containing micro-nano structures which significantly improves surface hydrophobicity. The combination of high porosity and hydrophobicity makes the membrane potentially applicable to the field of oil-water separation.