In-situ coating and surface partial protonation co-promoting performance of single-crystal nickel-rich cathode in all-solid-state batteries

The poor electrochemical performance of all-solid-state batteries(ASSBs),which is assemblied by Ni-rich cathode and poly(ethylene oxide)(PEO)-based electrolytes,can be attributed to unstable cathodic interface and poor crystal structure stability of Ni-rich cathode.Several coating strategies are previously employed to enhance the stability of the cathodic interface and crystal structure for Ni-rich cathode.However,these methods can hardly achieve simplicity and high efficiency simultaneously.In this work,polyacrylic acid(PAA)replaced traditional PVDF as a binder for cathode,which can achieve a uniform PAA-Li(LixPAA(0<x≤1))coating layer on the surface of single-crystal LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(SC-NCM83)due to H^(+)/Li^(+)exchange reaction during the initial charging-discharging process.The formation of PAA-Li coating layer on cathode can promote interfacial Li^(+)transport and enhance the stability of the cathodic interface.Furthermore,the partially-protonated surface of SC-NCM83 casued by H^(+)/Li^(+)exchange reaction can restrict Ni ions transport to enhance the crystal structure stability.The proposed SC-NCM83-PAA exhibits superior cycling performance with a retention of 92%compared with that(57.3%)of SC-NCM83-polyvinylidene difluoride(PVDF)after 200 cycles.This work provides a practical strategy to construct high-performance cathodes for ASSBs.

The Determination of the Protonation Constants of A New Macrocyclic Dinucleating Ligand, BDBPH

The protonation constants of a new dinucleating 24-membered hexaazadiphenol macrocyclic ligand, BDBPH, were determined by potentiometric measurement at 25.0 degreesC and mu = 0.100 mol.L-1 (KCl). The species distributions of the deprotonated and protonated compounds in the pH range from 2 to 12 aqueous solutions were also described.

Understanding De-protonation Induced Formation of Spinel Phase in Li-rich Layered Oxides for Improved Rate Performance

Constructing layered-spinel composites is important to improve the rate performance of lithium-rich layered oxides.However,up to now,the effect of microstructure of composites on the rate performance has not been well investigated.In this study,a series of samples were prepared by a simple protonation and de-protonation for the pristine layered material(LiMnNiCoO)obtained by sol-gel method.The characterizations of XRD,Raman and oxidation-reduction potentials of charge-discharge curves demonstrated that these samples after de-protonation are layered-spinel composites.When these composites were tested as a cathode of lithium-ion batteries,the sample treated with 0.1 M of nitric acid exhibited higher discharge capacities at each current density than that of other composites.The outstanding rate performance is attributed to the high concentration of conduction electron resulting from the low average valence state(44.2%of Ni)as confirmed by its high conductivity(1.124×10??mat39800Hz)and ambient temperature magnetic susceptibility(8.40×10emu/Oe?mol).This work has a guiding significance for the synthesis of high rate performance of lithium battery cathode materials.

Conjugate addition‐enantioselective protonation to forge tertiary stereocentresαto azaarenes via cooperative hydrogen atom transfer and chiral hydrogen‐bonding catalysis

Cooperative hydrogen atom transfer and chiral hydrogen‐bonding catalysis as a new platform for the asymmetric synthesis of azaarene derivatives is reported.By using a tetrabutylammonium decatungstate as the photocatalyst and a chiral phosphoric acid as the hydrogen‐bonding catalyst,transformations of a variety of commercially available hydrocarbons and silanes with diverseα‐branched 2‐vinylazaarenes could efficiently experience a tandem radical conjugate addition and enantioselective protonation process,providing a convenient and fully atom economical approach to access a range of valuable enantioenrichedα‐tertiary azaarenes in high yields with good to excellent enantioselectivities(up to 93%ee).Through the direct use of tert‐butyl methylcarbamate as the feedstock,this method enables a highly practical and concise synthesis of the enantiomerically pure medicinal molecule pheniramine(Avil).

Protonation effect on catalytic water oxidation activity of a mononuclear Ru catalyst containing a free pyridine unit

Two efficient single-site Ru water oxidation catalysts [Ru（bda）（pic）（Ln）] （bda=2,2＇-bipyridine- 6,6＇-dicarboxylic acid, pic=picoline, Ll=4,5-bipyridine-2,7-di-tett-butyl-9,9-dimethylxanthene, L2=4- pyridine-5-phenyl-2,7-di-tert-butyl-9,9-dimethylxanthene） were only synthesized containing different xanthene ligands at the axial site. These complexes have been thoroughly characterized by spectroscopic （UV-vis, NMR） and electrochemical （CV and DIV） techniques. Kinetic analysis proved that the mechanism of water oxidation comprises the water nucleophilic attack process on high-valence ruthenium species. It is found that the catalyst I displayed higher activity than catalyst 2 on water oxidation, caused by the protonation of the axial ligand LI with a free pyridine.

Synthesis,Characterization and Protonation Study of Novel Poly(thioether imide)s based on Aromatic Heterocyclic Diimide

Novel poly（thioether imide）s were synthesized by 2,5-dimercapto-l,3,4-thiadiazole, and aromatic heterocyclic chlorodiimids through nucleophilic!substitution reaction as alkali catalysts were presented. The poly（thioether imide）s exhibited good thermal property. The glass transition temperatures of polymers were around 373 ℃, and 10% weight loss temperatures were in the range of 450-500 ℃ in nitrogen/air atmosphere. Meanwhile, the chloroform dilute solutions of these polYmers could show strong UV-vis absorption peaks at about 289 nm. After being protonated by inorganic acids （HC1）, the new shoulder absorption peaks were observed at 350 nm. The PL absorption bands of polymer solutions were in the region of 350-550 nm, which showed the green-yellow fluorescence.

Protonation Effect on One- and Two-photon Absorption Property of a Newly Synthesized Octupolar Chromophore

The protonation effects on one- and two-photon absorption properties of an octupolar molecule TA with 1,3,5-triazine core and pyrrole electron-donating end-groups have been studied at hybrid density functional theory level. A computational scheme is developed to simulate a proton attached to an atom. The numerical results show that large changes in both one- and two-photon absorption properties are observed when the compound is transformed from neutral to threefold protonated states. When the compound is protonated, more charge transfer states appear and the absorption band has a red-shift. Furthermore, the two-photon absorption cross-section is largely enhanced. The theoretical calculations demonstrate the protonation effect on promoting the intramolecular charge transfer strength. The results present qualitative agreement with the experimental observations. A two-photon absorption switch with the compound TA based on the protonation effect is proposed.

Protonation of 5,10,15,20-Tetra(4-hydroxyphenyl)-porphyrin in SDS Micellar Solution

An amphiphilic porphyrin, 5, 10, 15, 20-tetra(4-hydroxyphenyl)-porphyrin (P) was solubilized in SDS micellar solutions. By taking advantage of protonation property of pyridine groups of amphiphilic porphyrin and the UV-Vis spectral sensitivity of Soret band and Q bands to the microenvironment of the porphyrin moiety, two-step protonation was studied in detail by means of UV-Vis spectroscopy. The free base, monocation and dication were described in detail in SDS micellar solution. The possibility of microphase transition was proposed to relate to the observation of two isosbestic points.

Sites of Protonation and Unimolecular Fragmentation of Protonated N-Hydroxyphthalimide in the Gas Phase

The low energy collisioninduced dissociation, linked scan techniques and isotopic labeling experiment were used to investigate the unimolecular fragmentation of protonated N-hydroxyphthalimide under electron impact and chemical ionization conditions. It was found that this compound shows an unusual reactivity towards protonation. Two possible sites of protonation have been proposed to explain the corresponding fragmentation processes, one is that the protonation takes place on the oxygen atom of hydroxyl group, resulting in the loss of water and the other is the formation of an intermediary protonbound complex in the fragmentation process, giving rise to the fragment ions of m/z 133 and m/z 135. The results show both cases are coexistence in the fragmentations of protonated N-hydroxyphthalimide, and the unimolecular fragmentation pathways are available.

Effect of Surface Protonation on Device Performance and Dye Stability of Dye-sensitized Ti02 Solar Cell

A flat thin TiO2 film was employed as the photo-electrode of a dye sensitized solar cell （DSSC）, on which only a geometrical mono-layer of dye was attached. The effect of sur- face protonation by HCI chemical treatment on the performance of DSSCs was studied. The results showed that the short-circuit current Jsc increased significantly upon the HCI treatment, while the open-circuit voltage Voc decreased slightly. Compared to the untreated DSSC, the Jsc and energy conversion efficiency was increased by 31% and 25%, respectively, for the 1 mol/L HCI treated cell. TiO2 surface protonation improved electronic coupling between the chemisorbed dye and the TiO2 surface, resulting in an enhanced electron in- jection. The decreased open-circuit voltage after TiO2 surface protonation was mainly due to the TiO2 conduction band edge downshift and was partially caused by increased electron recombination with the electrolyte. In situ Raman degradation study showed that the dye stability was improved after the TiO2 surface protonation. The increased dye stability was contributed by the increased electron injection and electron back reaction with the electrolyte under the open-circuit condition.

Modeling of the Chemico-Physical Process of Protonation of Molecules Entailing Some Quantum Chemical Descriptors

Relying upon the basic tenets of scientific modeling, an ansatz for the evaluation of proton affinity of mole-cules are evolved in terms of a four component model. The components of the model chosen are global de-scriptors like ionization energies, global softness, electronegativity and electrophilicity index. These akin quantum mechanical descriptors of atoms and molecules are linked with the charge rearrangement and polarization that occur during the physico-chemical process of protonation of molecules. The suggested ansatz is invoked to compute the protonation energy of as many as 43 compounds of diverse physico-chemical nature viz, hydrocarbons, alcohols, carbonyls, carboxylic acids, esters, aliphatic amines and aromatic amines. A detailed comparative study of theoretically evaluated protonation energies of the above mentioned molecules vis-à-vis their corresponding experimental counterparts reveals that there is a close agreement between the theory and experiment. Thus the results strongly suggest that the proposed modeling and the ansatz for computing PA, the proton affinity, of molecules for studying the physico-chemical process of protonation may be valid proposition.

Studies on the Protonation and Complexations of Dioxotetraamine Macrocycles

14-Membered macrocyclic dioxotetraamines deprotonate stepwisely upon coordination to cupric ions. Singly- and doubly-deprotonated complexes are the main species, While for 13-membered analogs, non- and doubly-deprotonated complexes are the main species.

Protonation Sites in Benzimidazolyl-Chalcones Molecules: An ab Initio and DFT Investigation

In this work, we have focused our investigations on the protonation sites predilection in the benzimidazolyl- chalcones (BZC) derivatives. Particularly, we are interested in the study of geometrical and energetical parameters. BZC are well known for their particularly nematicidal activity. Ten (10) BZC derivatives coded BZC-1 to BZC-10, with various larvicidal concentrations, have been selected for this work. They all are different one from another by the phenyl ring which is substituted by electron modulators such as alkyl, hydroxyl, alkoxy, aminoalkyl, halogen and nitro or replaced by the furan. Quantum chemical methods, namely HF/6-311 + G(d,p) and MPW1PW91/6- 311 + G(d,p) theory levels have been used to determine the geometrical and energetical parameters by the protonation on each heteroatom of the BZC derivative. An accuracy results with relatively less time consuming has been obtained using Hartree-Fock (HF) and Density Functional Theory methods (DFT/MPW1PW91). The calculations results allow identifying the sp2 nitrogen as the preferential site of protonation in BZC derivative compounds.

Protonation and Dehydrogenation During the Multiphoton Ionization of the Cluster:C_4H_5N(H_2O)_n

Multiphoton ionization (MPI) of the hydrogen-bonded clusters C4H5N-(H2O)(m) was studied with a time of flight (TOF) mass spectrometer at 355 nm. Series of the pyrrole-water cluster ions were observed, including unprotonated cluster ions [C4H5N-(H2O)(n)](+), protonated cluster ions [C4H5N-(H2O)(n)H](+) and dehydrogenated cluster ions [C4H4N-(H2O)(n)](+). Both the experimental and ab initio calculated results agree with that the dehydrogenation has more probabilities to occur while the value of n is raised.

Direct Observation of Transient Species Generated from Protonation and Deprotonation of the Lowest Triplet of p-Nitrophenylphenol

Photo-induced proton coupled electron transfer(PCET)is essential in the biological,photosynthesis,catalysis and solar energy conversion processes.Recently,p-nitrophenylphenol(HO-Bp-NO2)has been used as a model compound to study the photo-induced PCET mechanism by using ultrafast spectroscopy.In transient absorption spectra both singlet and triplet states were observed to exhibit PCET behavior upon laser excitation of HO-Bp-NO2.When we focused on the PCET in the triplet state,a new sharp band attracted us.This band was recorded upon excitation of HO-Bp-NO2 in aprotic polar solvents,and has not been observed for p-nitrobiphenyl which is without hydroxyl substitution.In order to find out what the new band represents,acidic solutions were used as an additional proton donor considering the acidity of HO-Bp-NO2.With the help of results in strong(~10^-1 mol/L)and weak(~10^-4 mol/L)acidic solutions,the new band is identified as open shell singlet O-Bp-NO2H,which is generated through protonation of nitro O in 3HO-Bp-NO2 followed by deprotonation of hydroxyl.Kinetics analysis indicates that the formation of radical·OBp-NO2 competes with O-Bp-NO2H in the way of concerted electron-proton transfer and/or proton followed electron transfers and is responsible for the low yield of O-Bp-NO2H.The results in the present work will make it clear how the3HO-Bp-NO2 deactivates in aprotic polar solvents and provide a solid benchmark for the deeply studying the PCET mechanism in triplets of analogous aromatic nitro compounds.

Synchronous deprotonation–protonation for mechanically robust chitin/aramid nanofibers conductive aerogel with excellent pressure sensing, thermal management, and electromagnetic interference shielding

Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors,electromagnetic shielding,and so on.However,the poor mechanical properties of the emerging nanofibers-based aerogels are limited in practical applications.In this work,we developed a synchronous deprotonation–protonation method in the KOH/dimethyl sulfoxide(DMSO)system at room temperature for achieving chitin cross-linked aramid nanofibers(CANFs)rather than chitin nanofibers(ChNFs)and aramid nanofibers(ANFs)separately by using chitin and aramid pulp as raw materials.After freeze-drying process,the cross-linked chitin/aramid nanofibers(CA)aerogel exhibited the synergetic properties of ChNF and ANF by the dual-nanofiber compensation strategy.The mechanical stress of CA aerogel was 170 kPa at 80%compressive strain,increased by 750%compared with pure ChNF aerogel.Similarly,the compressibility of CA aerogel was somewhat improved compared to ANF aerogel.The enhancement verified that the crosslinking reaction between ANF and ChNF during the synchronous deprotonation process was formed.Afterwards,the conductive aerogels with uniform porous structure(CA-M)were successfully obtained by vacuum impregnating CA aerogels in Ti_(3)C_(2)T_(x) MXene solution,displaying low thermal conductivity(0.01 W/(m·K)),high electromagnetic interference(EMI)shielding effectiveness(SE)(75 dB),flame retardant,and heat insulation.Meanwhile,the as-obtained CA-M aerogels were also applied as a pressure sensor with excellent compression cycle stability and superior human motion monitoring capabilities.As a result,the dual-nanofiber based conductive aerogels have great potentials in flexible/wearable electronics,EMI shielding,flame retardant,and heat insulation.

In situ protonation in a locally flexible porous coordination polymer for enhancing proton-carrier loading and proton conductivity

Designing efficient proton-conductive materials is crucial in fuel cells.Yet,it remains a substantial challenge because of the issues in proton mobility,proton-carrier amount,and orientation of proton host materials.Herein,we report an in-situ protonation strategy to produce a locally flexible porous coordination polymer(PCP)to enhance the proton-carrier loading and proton conductivity.The local dipole flipping of the ligand allows effective proton exchange with low activation energy,promoting interpore proton transport through the pore apertures and pore walls.The protonation induces substantial charges to the frameworks and enhances the interaction with proton carriers,thereby increasing the loading of the proton carriers.By this design strategy,the resulting PCP exhibits enhanced phosphoric acid loading and extraordinary proton conductivities under both aqueous and anhydrous conditions compared to its isoreticular analog that features rigidity without proton-exchange capability.Our work provides a new avenue for designing proton-conductive materials that combine structural dynamics with performance merits.

Negative differential resistance effects induced by protonation in naphthalocyanine molecular junctions

The electronic and transport characteristics of protonated derivatives of naphthalocyanine(Nc)were investigated using density functional theory and non-equilibrium Green's functions.The results indicate that the protonation of external meso-N atoms of Nc preserves its planar structure and is energetically more favorable than the protonation of internal isoindole-N atoms.The protonation shifts the energy levels of system's frontier molecular orbitals closer to the Fermi level,thus creating channels for electron transport.In contrast with the semiconductor transport properties of H2Nc,its protonation products respond more sensitively to bias and exhibit negative differential resistance phenomena at specific bias.

Ynamide Protonation-Initiated Cis-Selective Polyene Cyclization and Reaction Mechanism

The diastereoselectivity of conventional polyene cyclization reactions is highly dependent on the configuration of the internal alkenes,where E-poly enes provide trans-decalins,while Z-polyenes offer cis-decalins.Although polyene cyclization has evolved into a reliable and widely used strategy for the construction of trans-decalin frameworks of terpene and steroid natural products,its application for cis-decalin framework is extremely challenging.