Dissociation Of Anions Research Articles

Dynamics of hydride anion and acetyloxyl radical production by electron attachment to acetic acid.

We investigate the dynamics and site-selectivity in the dissociation of transient anions formed upon attachment of low energy electrons to acetic acid by anion fragment momentum imaging experiments. The resonances at 6.7 and 7.7eV are confirmed to dissociate exclusively by the O-H bond, while a third resonance at 9.1eV dissociates primarily by both C-H break and O-H break. A fourth resonance near 10eV is found to dissociate by O-H break. For each resonance, the measured kinetic energy release indicates two-body dissociation produces a neutral radical in the ground electronic state, for all four resonances. The measured angular distributions are consistent with all four resonances having A' symmetry.

Cationic Covalent Organic Framework-Modified Polypropylene Separator for High-Performance Lithium Metal Batteries.

As an important component of lithium batteries, the wettability and thermal stability of the separator play a significant role in cell performance. Despite the availability of numerous commercial separators, issues such as low ion selectivity and poor thermal stability continue to limit the efficiency and reliability of the batteries. Herein, two cationic covalent organic frameworks (Br-COF and TFSI-COF) with abundant imidazole cationic groups were designed to modify commercial polypropylene (PP) separators. The strong lithium-ion affinity of the cationic COF enables the effective dissociation of lithium salt ion clusters, simplifying the solvent structure of lithium ions to promote lithium ions transport. Additionally, solvent anions can be anchored to the cationic COF by electrostatic interactions, reducing side reactions on the lithium metal anode surface to form a favorable SEI layer, which can effectively inhibit the growth of lithium dendrites. The rapid dissociation of anions in lithium salts with some organic solvents and cationic COFs was revealed by a molecular dynamics simulation. A LiF-rich SEI layer on the lithium metal anode surface was formed, which can speed up Li+ transport at interfaces, leading to consistent lithium deposition and outstanding battery performance. The ordered porous structure of the cationic COF provides interconnected and continuous channels, improving the wettability between the liquid electrolyte and separators, which is conducive to ion transport. When paired with a LiFePO4 cathode and electrolyte (1.0 M LiTFSI in DEC: EC: DMC = 1:1:1), the LiFePO4/TFSI-COF@PP/Li cell demonstrates a prominent cycling capacity of 148.0 mAh g-1 at 0.5 C with a Coulombic efficiency of 98.0% in the first cycle, and the capacity retention is 82.0% after 100 cycles, showing good cycling stability. Thus, this investigation provides inspiration for the expansion of cationic COF-modified separators for next-generation lithium metal batteries.

Understanding the role of tungsten species in diamond-like carbon coatings for enhanced interaction with ionic liquids

This study investigated the impact of tungsten species in tungsten-doped diamond-like carbon (WDLC) coatings on their interactions with ionic liquids (ILs). Using analytical techniques such as in-situ neutron reflectometry, time-of-flight secondary ion mass spectrometry, and Raman spectroscopy, we examined the adsorption mechanism of tributylmethylphosphonium dimethylphosphate on WDLC and undoped hydrogenated DLC (hDLC) coatings. These techniques provide high-resolution insights into the molecular interactions, revealing that tungsten doping enhances the formation of tungsten carbide and tungsten oxides. These species facilitate the dissociation of dimethylphosphate anions, forming a robust 0.75 nm-thick tungsten phosphate layer on the WDLC surfaces. This layer, which adheres strongly even after cleaning, underscores the role of tungsten in enhancing the effectiveness and lubrication properties of WDLC coatings with ILs.

Deciphering the Decomposition Mechanisms of Ether and Fluorinated Ether Electrolytes on Lithium Metal Surfaces: Insights from CMD and AIMD Simulations.

The performance of lithium metal batteries can be significantly enhanced by incorporating fluorinated ether-based electrolytes, yet the solid electrolyte interphase (SEI) formation mechanism on lithium metal surfaces remains elusive. This study employs classical and ab initio molecular dynamics simulations to investigate the decomposition mechanisms of lithium bis(fluoromethanesulfonyl)imide (LiFSI) in 1,2-diethoxyethane (DEE) and its fluorinated analogues, F5DEE and F2DEE, when in contact with lithium metal. Our findings indicate that F5DEE-based electrolytes favor the formation of a FSI-rich primary solvation shell around Li+, while F2DEE-based electrolytes yield a solvent-rich environment. The normalized number density at the Li/electrolyte/Li interface shows a depletion of FSI anions in the electrochemical double layer (EDL) structure near the Li anode upon charging, with the distance between the first main peak of the FSI anion and Li anode following the order F5DEE < DEE < F2DEE. Analysis of the electronic projected density of states and charge transfer dynamics unveils the reductive dissociation pathways of FSI anions and fluorinated DEE solvents on the lithium metal surface, taking into account the influence of the EDL structure. DEE is identified as the most reduction-stable solvent, leading to the selective dissociation of FSI anions and the formation of an entirely inorganic SEI. In contrast, F2DEE displays a pronounced reduction tendency, forming an organic-rich SEI due to the solvent-dominated lowest unoccupied molecular orbital at the interface. F5DEE, competing with FSI anions for reduction, results in the formation of an inorganic-rich hybrid SEI with the highest LiF content. The simulation results correlate well with experimental observations and underscore the pivotal role of various fluorinated functional groups in the formation of EDL and SEI near the lithium metal surface.

Effect of Terminal Phosphate Groups on Collisional Dissociation of RNA Oligonucleotide Anions.

The increasing need for mass spectrometric analysis of RNA molecules calls for a better understanding of their gas-phase fragmentation behaviors. In this study, we investigate the effect of terminal phosphate groups on the fragmentation spectra of RNA oligonucleotides (oligos) using high-resolution mass spectrometry (MS). Negative-ion mode collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD) were carried out on RNA oligos containing a terminal phosphate group on either end, both ends, or neither end. We find that terminal phosphate groups affect the fragmentation behavior of RNA oligos in a way that is dependent on the precursor charge state and the oligo length. Specifically, for precursor ions of RNA oligos of the same sequence, those with 5'- or 3'-phosphate, or both, have a higher charge state distribution and lose the phosphate group(s) in the form of a neutral (H3PO4 or HPO3) or an anion ([H2PO4]- or [PO3]-) upon CID or HCD. Such a neutral or charged loss is most conspicuous for precursor ions of an intermediate charge state, e.g., 3- for 4-nt oligos or 4- and 5- for 8-nt oligos. This decreases the intensity of sequencing ions (a-, a-B, b-, c-, d-, w-, x-, y-, z-ions) and hence is unfavorable for sequencing by CID or HCD. Removal of terminal phosphate groups by calf intestinal alkaline phosphatase improved MS analysis of RNA oligos. Additionally, the intensity of a fragment ion at m/z 158.925, which we identified as a dehydrated pyrophosphate anion ([HP2O6]-), is markedly increased by the presence of a terminal phosphate group. These findings expand the knowledge base necessary for software development for MS analysis of RNA.

Electrochemical Doping of Two-Dimensional Superatomic Materials.

We report an electrochemical method for doping two-dimensional (2D) superatomic semiconductor Re6Se8Cl2 that significantly improves the material's electrical transport while retaining the in-plane and stacking structures. The electrochemical reduction induces the complete dissociation of chloride anions from the surface of each superatomic nanosheet. After the material is dehalogenated, we observe the electrical conductivity (σ) increases by two orders of magnitude while the 3D electron carrier density (n3D) increases by three orders of magnitude. In addition, the thermal activation energy (Ea) and electron mobility (μe) decrease. We conclude that we have achieved effective electron-doping in 2D superatomic Re6Se8Cl2, which significantly improves the electrical transport properties. Our work sets the foundation for electrochemically doping and tuning the transport properties of other 2D superatomic materials.

Tailoring Practical Solid Electrolyte Composites Containing Ferroelectric Ceramic Nanofibers and All-Trans Block Copolymers for All-Solid-State Lithium Metal Batteries.

Ion transport efficiency, the key to determining the cycling stability and rate capability of all-solid-state lithium metal batteries (ASSLMBs), is constrained by ionic conductivity and Li+-migration ability across the multicomponent phases and interfaces in ASSLMBs. Here, we report a robust strategy for the large-scale fabrication of a practical solid electrolyte composite with high-throughput linear Li+-transport channels by compositing an all-trans block copolymer PVDF-b-PTFE matrix with ferroelectric BaTiO3-TiO2 nanofiber films. The electrolyte shows a sustainable electromechanical-coupled deformability that enables the rapid dissociation of anions with Li+ to create more movable Li+ ions and spontaneously transform the battery internal strain into Li+-ion migration kinetic energy. The ceramic framework homogenizes the interfacial potential with electrodes, endowing the electrolyte with a high conductivity of 0.782 mS·cm-1 and stable ion transport ability in ASSLMBs at room temperature. The batteries of LiFePO4/Li can stably cycle 1000 times at 0.5 C with a high capacity retention of 96.1%, and Ah-grade pouch or high-voltage Li(Ni0.8Mn0.1Co0.1)O2/Li batteries also exhibit excellent rate capability and cycling performance.

Carbon dots promoting surface defect and interphase high anion concentration for sodium-ion battery carbon anodes

The interphase chemistry of electrode/electrolyte significantly affects the electrochemical performance. This investigation explores the solid-liquid interphase alteration of an economical asphalt-derived carbon by incorporating multifunctional carbon dots, aiming to clarify the impact of interfacial properties on sodium-ion storage mechanisms. Enhanced by high density defects and carbonyl groups, the capacity, primarily within the sloping discharge, rise from 247 to 361 mA h g−1 in non-aqueous sodium ion batteries. Integrating experimental and computational methods reveals a marked improvement in PF6- anions absorption at the interface, refining the solvation structure and concentrating these anions. Consequently, a NaF/Na2CO3-dominated, inorganic-rich solid-electrolyte interphase (SEI) forms, attributed to the swift PF6- anion dissociation facilitated by the electrode's rapid electron mobility. This effect promotes sodium ion diffusion and accelerates the kinetics of sodium (de)intercalation. Beyond elucidating interfacial property contributions to the sodium storage in disordered carbon, this study highlights the genesis of irreversible capacity and draws connections between SEI's inorganic components and Coulombic efficiency. The insights offered furnish a pioneering perspective for engineering high-performance carbon anodes.

Rational design of blue TADF host of various polarity according to cyano- group applicable to blue thermally activated delayed fluorescence emitter

Although remarkable progress has been made in the field of blue organic light-emitting diodes (OLEDs), many challenges persist. In particular, the emitting material layer of an OLED is composed of a host and a dopant, and the host material has a significant influence on the device efficiency and lifetime along with the dopant. Therefore, in this study, 9-(2′-(dibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-3-yl)-9H-carbazole, 3′-(9H-carbazol-9-yl)-2-(dibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-3-carbonitrile, and 3′-(9H-carbazol-9-yl)-2-(dibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-4-carbonitrile were synthesised to investigate the changes in the device efficiency and lifetime through various properties such as the polarity of the host molecule and anionic bond dissociation energies (BDEs) according to the substitution position of the CN group. In addition, 2,4,6-tris(2-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)-1,3,5-triazine, a blue thermally activated delayed fluorescence dopant, was synthesised and evaluated. The roll-off at 5000 nit decreased from 30.2% to 21.9% depending on the polarity of the host molecule, whereas the lifetime increased from 7.95 to 15.5 h according to the anionic BDE of blue thermally activated delayed fluorescence hosts.

DLPNO-CCSD(T) and DFT study of the acetate-assisted C-H activation of benzaldimine at [RuCl2(p-cymene)]2: the relevance of ligand exchange processes at ruthenium(II) complexes in polar protic media.

To gain mechanistic insights into the acetate-assisted cyclometallations of arylimines promoted by [RuCl2(p-cymene)]2 in polar protic media, DFT geometry optimizations (with M06 and ωB97X-D3 functionals and the cc-pVDZ-PP[Ru] basis set) followed by DLPNO-CCSD(T)/CBS energy evaluations were performed using benzaldimine as a model substrate and methanol as the solvent (with CPCM or SMD models). The calculation results show that coordination of the imine to an acetate ruthenium precursor is followed by anion (chloride or acetate) dissociation as the rate-determining step of the process. H-Bonding of two explicit MeOH to the anion reduces the calculated activation energy to ca. 23 kcal mol-1, in good agreement with the experimental half-life at room temperature. Subsequent AMLA/CMD C-H activation of the intermediate cationic complexes is a faster, reversible process. Alternative reaction pathways involving neutral diacetate ruthenium complexes offer AMLA/CMD transition state structures of lower energy but are precluded due to higher energy barriers for the initial ligand exchange processes at ruthenium. Solvent assistance accelerates the final chloride/acetate exchange processes on the cycloruthenate intermediates, particularly when compression in the condensed phase is taken into consideration. The performance of six DFT functionals (with the aug-pVTZ-PP[Ru] basis set) was assessed using the DLPNO-CCSD(T)/CBS reference energies. Neutral diacetate ruthenium complexes were incorrectly predicted as being kinetically relevant when using hybrid DFT methods (PBE0-D3(BJ), M06-2X or ωB97M-V). Good agreement between the calculated barrier heights and our benchmark energy results was obtained by using double-hybrid DFT methods. PWPB95 with D3(BJ) or D4 dispersion energy corrections was found to be the most accurate (ΔG≠ MUE of ca. 1 kcal mol-1). This study may aid our understanding of and help with further experimental investigations of synthetically useful carboxylate-assisted C-H bond functionalizations involving (N,C)-cyclometallated (p-cymene)Ru(II) intermediate complexes in sustainable polar protic solvents.

Understanding How Anion Exchange Membranes and Cationic Polymer/Catalyst Interactions Behave with Time in Alkaline Electrolysis

We are leveraging our existing success with anion exchange membranes (AEM) to develop new highly stable and highly conductive membranes and ionomers for AEM electrolysis. Our novel and scalable tri-block co-polymers ABA or BAB, where the A block can be functionalized with an advanced chemically stable cation and the B block is an unsaturated polymer that when hydrogenated results in high anion conduction membranes with exceptional mechanical strength and durability analogous to polyethylene (PE). We have also developed a novel immobilization technology for processable catalyst inks. Synergistically the A and B block lengths and chemistries are tuned to achieve all the properties desirable for an anion exchange membrane for electrolyzer applications. Random polymers of the same A and B chemistries can also be formulated for additional fidelity in chemically compatible ionomers for the membrane electrode assemblies (MEA). These systems are unique in that they achieve very high dissociation of anions beyond OH-, giving CO3 2- σ<100 mS cm-1 ca. 60°C and enhanced chemical stability as the water is separated from the high MW polyethylene backbone that additionally gives the materials unprecedented strength. This will allow us to fabricate thinner membranes for long durability pressure differentiated operation. Because of the unusual and exceptional CO3 2- conductivity that we have designed into our membrane, we are able to optimize these for a carbonate electrolyte electrolyzer. While we lose a 100 mV in activity compared to operation in OH-, the advantages including high current densities enabled by our novel membrane outweigh that disadvantage. Chemical stability of the membrane is not a concern, and the system is less complicated as we do not need to use expensive components to protect against caustic corrosion or protect the hydroxide electrolyte from carbon dioxide present in air to avoid its inevitable conversion to CO3 2-.Not all proposed AEM polymer chemistries are scalable, many involve too many synthetic steps, suffer from low overall yields, and are highly exothermic reactions (thus only safely executed on a small scale), or do not produce sufficiently high molecular weight for film formation. The polymer systems proposed here have already been demonstrated on the 1 kg scale. This novel AEM intellectual property, jointly invented by Mines and UMass, has been licensed to Spark Ionix who are commercializing an early version of this polymer technology. The next generation of tailored polymers proposed are increasingly robust, scalable, efficient and more amenable to high volume manufacture to produce inexpensive hydrocarbon polymer membranes for use in electrolyzers. The block lengths, overall molecular weight and chemistries are completely tunable to fabricate AEMs with all desired properties or compatible ionomer chemistries that allow high levels of catalyst utilization, through both ionic conductivity and chemical transport. We have been investigating this polymer system in 1M K2CO3 at 50°C with great success and have shown good performance and durability in 5cm2cells. We are developing the system for >60°C and 25 cm2 cells. We have begun to understand the science behind ionomer catalyst interactions and initially used a commercial Ag nano-catalyst as a model system. Few ave studied the effect of ionomer chemistry and catalyst or catalyst type and loadings on performance. We have shown durability of > 600 h at 0.5 A cm-2 and continue to see improvements. It should be noted that the voltage is dropping in theses tests, at end of test at –ve 60 µV h-1 is achieved, while this may be interpreted as evidence of membrane thinning when the cell was dissembled the membrane thickness was ca. the same as at the beginning of test (80 µm), indicating slow, but long term conditioning, the cell did not reach the point at which a +ve degradation rate was observed. Further investigation of cell conditioning indicated that these cells currently take 40-50 hs under load to reach steady state operation (this break in time will be understood and significantly shortened) giving 400MV improvement at 1 A cm-2. With a MnO2 catalyst the voltage at 0.5 A cm-2drops to 1.5 V indicating that the target of 2 A cm-2 at 1.8 V will be easily achieved with further investigation.

Highly reduced efficiency roll-off with 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-containing unit on bipolar host for improved OLEDs device lifespan

The electrical, thermal, and optical properties of the host material used in the light-emitting layer of a thermally activated delayed fluorescence organic light-emitting diode (TADF-OLED) directly affect its efficiency, lifetime, and color. In this study, a new host material was designed, synthesized, and then applied to a green TADF-OLED device to evaluate its performance as a host. The host material was designed in a bipolar configuration, ensuring the balanced introduction and transport of electrons and holes. This balance was achieved by incorporating a carbazole unit to facilitate hole injection and transport. Moreover, a 5,9-dioxa-13b-boranaphtho [3,2,1-de]anthracene (DOBNA) unit containing a boron atom was introduced for electron injection and transport. These units were linked to ortho terphenyl spacers. The DOBNA unit improved the electron transport properties, the thermal stability of molecule, and anionic bond dissociation energy. Consequently, the device evaluated using the DOBNA-introduced material as a host for 4CzIPN, a TADF dopant, enhanced the performance by ∼ four times from LT80@1000 nit to 15.1 h compared to the unipolar host material comprising carbazole and ortho-terphenyl.

Enable reversible conversion reaction of copper fluoride batteries by hydroxyl solution and anion acceptor

Metal fluorides as conversion-reaction cathodes are attracting more attentions due to their advantages of low cost, environmentally friendly and high energy density. Among CuF2 enables the high theoretical energy density (1874 Wh/kg) and conversion reaction potential (3.55 V vs. Li+/Li), but its poor reversibility is always criticized due to the dissolution of Cu species occurring in delithiation process. In response to this conundrum, here we propose a hydroxyl‑rich copper fluoride (Cu2(OH)3F) as conversion cathode coupled with an electrolyte additive engineering to address the reversibility bottleneck. The presence of OH enables the effective suppression of Cu+ dissolution and imparts Cu2(OH)3F a phase-division conversion mechanism, resulting in the better reaction reversibility and kinetics. Combing with the electrolyte formulation based on boron-based anion acceptor with mild Lewis acidity, the dissociation and conversion of anions from Cu2(OH)3F lattices are promoted and hence the cycling performance is further upgraded, with a reversible capacity over 200 mA h/g after 50 cycles.

Mass-selected ion-molecule cluster beam apparatus for ultrafast photofragmentation studies.

We describe an apparatus for investigating the excited-state dissociation dynamics of mass-selected ion-molecule clusters by mass-resolving and detecting photofragment-ions and neutrals, in coincidence, using an ultrafast laser operating at high repetition rates. The apparatus comprises a source that generates ion-molecule clusters, a time-of-flight spectrometer, and a mass filter that selects the desired anions, and a linear-plus-quadratic reflectron mass spectrometer that discriminates the fragment anions after the femtosecond laser excites the clusters. The fragment neutrals and anions are then captured by two channeltron detectors. The apparatus performance is tested by measuring the photofragments: I-, CF3I-, and neutrals from photoexcitation of the ion-molecule cluster CF3I·I- using femtosecond UV laser pulses with a wavelength of 266nm. The experimental results are compared with our ground state and excited state electronic structure calculations as well as the existing results and calculations, with particular attention to the generation mechanism of the anion fragments and dissociation channels of the ion-molecule cluster CF3I·I- in the charge-transfer excited state.

Unraveling the Ag+ ion coordination and solvation thermodynamics in the 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

The solvation of the Ag+ ion in the 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) ionic liquid (IL) has been studied by means of experimental and theoretical methods with the aim of elucidating the cation coordination structure and thermodynamic properties. Car-Parrinello molecular dynamics (CPMD) simulations showed that the Ag+ ion is coordinated by an average number of four [BF4]− anions in a pseudo-tetrahedral geometry. A high configurational disorder of the first solvation sphere is found, where the anions can be found both in mono- and bidentate coordination mode around the Ag+ ion. Also, a solvational equilibrium is observed as due to [BF4]− anion dissociation along the trajectory. The analysis of X-ray absorption spectroscopy data confirmed the picture provided by the CPMD simulation. Classical molecular dynamics simulations were carried out to obtain the single-ion solvation thermodynamic parameters. The negative water → IL free energy of transfer suggests that the Ag+ ion is more favorably solvated in the [C4mim][BF4] IL than in water. This behavior is due to a balance between the enthalpic and entropic contributions, which allows to find a rationale to the strong solvation capabilities of BF4-based ILs towards Ag+.

Lamellar Ionenes with Highly Dissociative, Anionic Channels Provide Lower Barriers for Cation Transport.

Solid polymer electrolytes have the potential to enable safer and more energy-dense batteries; however, a deeper understanding of their ion conduction mechanisms, and how they can be optimized by molecular design, is needed to realize this goal. Here, we investigate the impact of anion dissociation energy on ion conduction in solid polymer electrolytes via a novel class of ionenes prepared using acyclic diene metathesis (ADMET) polymerization of highly dissociative, liquid crystalline fluorinated aryl sulfonimide-tagged ("FAST") anion monomers. These ionenes with various cations (Li+, Na+, K+, and Cs+) form well-ordered lamellae that are thermally stable up to 180 °C and feature domain spacings that correlate with cation size, providing channels lined with dissociative FAST anions. Electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC) experiments, along with nudged elastic band (NEB) calculations, suggest that cation motion in these materials operates via an ion-hopping mechanism. The activation energy for Li+ conduction is 59 kJ/mol, which is among the lowest for systems that are proposed to operate via an ion conduction mechanism that is decoupled from polymer segmental motion. Moreover, the addition of a cation-coordinating solvent to these materials led to a >1000-fold increase in ionic conductivity without detectable disruption of the lamellar structure, suggesting selective solvation of the lamellar ion channels. This work demonstrates that molecular design can facilitate controlled formation of dissociative anionic channels that translate to significant enhancements in ion conduction in solid polymer electrolytes.

Anion‐Modulated Chemical Doping of Organic Hole Conductor Boosts Efficiency and Stability of Perovskite Solar Cells (Adv. Funct. Mater. 8/2023)

Charge Conductors In number 2211304, Jinbao Zhang, Li Yang, and co-workers reveal the important roles of degree of delocalization of anions in determining the hole-transport mechanism and device photostability. A versatile strategy of Li+ solvation is developed to modulate anion dissociation, enabling simultaneous improvement of device efficiency and stability. This approach can be generally applied to optimize the properties of doped organic semiconductors.

Anion‐Modulated Chemical Doping of Organic Hole Conductor Boosts Efficiency and Stability of Perovskite Solar Cells

AbstractChemical doping of organic semiconductors enables significant progress in improving their optoelectronic performance. However, the correlation between doping counter ions and charge‐transport mechanism has not been yet well‐understood. In this study, it is discovered that the anion‐dependent degree of delocalization (DOD) of lithium‐based dopants significantly determines the doping kinetics as well as the conductivity of organic hole transport layer (HTL), leading to large variation in solar cell efficiency and device stability. Specifically, the incorporation of bis(pentafluoroethanesulfonyl) imide (PFSI−) as the anion with a high DOD results in one order of magnitude higher film conductivity and thus an elevated power conversion efficiency (PCE) exceeding 22.1%, much higher than the state‐of‐the‐art lithium bis(trifluoromethane)sulfonimide (LiTFSI) (21.1%) and lithium hexafluorophosphate (LiPF6) (20.0%). Moreover, the dopant LiPF6 with a smaller DOD produces higher doping yield of HTL accompanied by stronger light‐induced PCE fluctuation. Structural analysis reveals anion‐modulated ion exchange kinetics determine the hole‐transport mechanism and device photostability. To mitigate these detrimental effects, a versatile strategy of Li+ solvation is developed to modulate the anion dissociation, enabling simultaneous improvement of device efficiency and stability. This study elucidates an intriguing and generally applicable doping mechanism, and envisages a bright future to further developing efficient and stable organic electronics.

Zinc borate modified multifunctional ceramic diaphragms for lithium-ion battery

Polyethylene(PE) diaphragm has become broadly used in lithium-ion battery systems because of its high strength, exceptional plasticity, and resistance to organic solvents. Nevertheless, the lack of polar groups on the surface of the PE diaphragms has a little significant effect on the ionic polarity of the electrolyte. Consequently, the electrolyte has poor wettability, the lithium-ion migration number t Li + (0.21) and the ion conductivity σ (0.63 mS/cm) still need to be further improved, which restricts its application to a certain extent. In this work, the high-purity zinc borate modified PE diaphragms with Lewis acid sites were prepared via a simple solid-state method. The multifunctional diaphragms modified by zinc borate have the following advantages: (1) The Zn–O bond and -BO 3 group in the structure have a polar bond and Lewis acid action, respectively, which can promote the desolvation of lithium ions and the dissociation of anions and cations, thereby increasing the concentration of free ions. In addition, zinc borate and anions have a specific binding effect, which can inhibit the migration of anions, consequently increasing t Li + (0.41) and σ (1.14 mS/cm); (2) Zinc borate was a commonly used flame retardant, which was conducive to improving the thermal stability of the PE diaphragms; (3) The surface of the modified diaphragms is rougher, which can increase the specific surface area of the diaphragm, hence enhancing its liquid absorption capacity. The electrochemical performance test results show that the modification of zinc borate can effectively improve the comprehensive performance of the PE diaphragm and the overall cycle stability and rate performance of the lithium iron phosphate battery.

Integrated Bending Actuation and the Self‐Sensing Capability of Poly(Vinyl Chloride) Gels with Ionic Liquids

AbstractSoft actuation materials often only perform an actuation function, and do not achieve the function of self‐sensing. In this work, the polyvinyl chloride (PVC) gels are prepared with a plasticizer of dibutyl adipate (DBA) and small amount of imidazolium type ionic liquids (ILs), and are demonstrated that the PVC/DBA/ILs gels deliver the integrated bending actuation and capacitance pressure self‐sensing capability. The bending actuation performances and sensing behavior of PVC/DBA/ILs are related to the migrability of movable ions from ILs, which are dependent on the dissociation of anions and cations of ILs, and the concentration of ILs. Among the ILs, the PVC/DBA gel with 3.3 wt% 1‐allyl‐3‐methylimidazolium bis ((trifluoromethyl)sulphonyl) imide (P/[AMIM]NTF2 (3.3 wt%)) exhibits best bending displacement of 6.6 mm (corresponding to 24° of bending angle) at 7.2 kV (180 V mm−1 of nominal electric field). In addition, the P/[AMIM]NTF2 (3.3 wt%) exhibits 0.42 kPa–1 capacitance pressure sensitive in the pressure range 0 to 2.2 kPa, and a sudden change in capacitance in the pressure range 2.2–2.7 kPa with 47.5 kPa–1 of sensitivity. The results can provide a new idea for developing integrated sensing and actuation functions of electroactive dielectric polymer gels.