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A 2-fold interpenetrated Zn-MOF with Lewis basic triazole sites shows selective luminescence sensing of Fe3+ and Cr2O72− and tunable white-light emission by encapsulated Ln3+ ions.

Lithium metal anodes (LMAs) with high energy density have recently captured increasing attention for development of next-generation batteries. However, practical viability of LMAs is hindered by the uncontrolled Li dendrite growth and infinite dimension change. Even though constructing 3D conductive skeleton has been regarded as a reliable strategy to prepare stable and low volume stress LMAs, engineering the renewable and lithiophilic conductive scaffold is still a challenge. Herein, a robust conductive scaffold derived from renewable cellulose paper, which is coated with reduced graphene oxide and decorated with lithiophilic Au nanoparticles, is engineered for LMAs. The graphene cellulose fibres with high surface area can reduce the local current density, while the well-dispersed Au nanoparticles can serve as lithiophilic nanoseeds to lower the nucleation overpotential of Li plating. The coupled relationship can guarantee uniform Li nucleation and unique spherical Li growth into 3D carbon matrix. Moreover, the natural cellulose paper possesses outstanding mechanical strength to tolerate the volume stress. In virtue of the modulated deposition behaviour and near-zero volume change, the hybrid LMAs can achieve reversible Li plating/stripping even at an ultrahigh current density of 10 mA cm-2 as evidenced by high Coulombic efficiency (97.2 % after 60 cycles) and ultralong lifespan (1000 cycles) together with ultralow overpotential (25 mV). Therefore, this strategy sheds light on a scalable approach to multiscale design versatile Li host, promising highly stable Li metal batteries to be feasible and practical.

Five new nuclear coordination complexes based on a 2-hydroxymethylpyridine (Hhmp) ligand, [Cu4(hmp)4(CHOO)2(H2O)2](ClO4)2·2H2O (1), [Cu8(hmp)8(CHOO)4(CH3CN)2(H2O)4](ClO4)4·2CH3CN (2), {[Cu2(hmp)2(C...

The effects of functional groups (including OH, OCH3 , NH2 , CH2 NH2 , COOH, SO3 H, OCO(CH2 )2 COOH(E-COOH), and (CH2 )4 COOH(c-COOH)) in 3D covalent organic frameworks (3D-COFs) on CO2 adsorption and separation are investigated by grand canonical Monte Carlo (GCMC) simulations and density functional theory calculations. The results indicate that interaction between CO2 and the framework is the main factor for determining CO2 uptakes at low pressure, while pore size becomes the decisive factor at high pressure. The binding energy of CO2 with functionalized linker is correlated to CO2 uptake at 0.3 bar and 298 K on 3D-COF-1, suggesting functional groups play a key role in CO2 capture in microporous 3D-COFs. Moreover, CO2 selectivity over CH4 , N2 , and H2 can be significantly enhanced by functionalization, where CH2 NH2 , COOH, SO3 H, and E-COOH enhance CO2 adsorption more effectively at 1 bar. Among them, SO3 H is the most promising functional group in 3D-COFs for CO2 separation.

Preparation of a material with excellent rate performance and high capacity contribution is significant for sodium-ion hybrid capacitors (SIHCs). TiO2 has been extensively studied due to its outstanding chemical stability, but the low specific capacity greatly hinders its practical application. Herein, TiO2 with a foveolate-shape is prepared via a precisely controlled Ostwald maturation procedure. Benefiting from the unique structure, foveolate TiO2 possesses satisfactory electrochemical performance. When used as the anode for SIHCs, a high reversible specific capacity of 290 mA h g−1 is obtained with an ultrahigh initial coulombic efficiency of 96% at 100 mA g−1. Even if the current density increases to 1000 mA g−1, the specific discharge capacity can still be maintained at 158 mA h g−1 after 1500 cycles. To further improve its capacity, the TiO2@MoSe2 composite electrode is synthesized by using foveolate TiO2 as the skeleton for the successful growth of MoSe2 nanosheets. A higher reversible specific capacity of 551 mA h g−1 is achieved at 100 mA g−1. Moreover, a reversible specific capacity of 164 mA h g−1 is maintained after 500 cycles at 5000 mA g−1. The foveolate TiO2 preparation method developed in this work provides new ideas for the development of both substrate materials and active materials in the field of energy storage.

Angiogenesis occurs during the process of tumor growth, invasion and metastasis, and is essential for the survival of solid tumors. As an integrin significantly overexpressed in human tumor vascular endothelial cells, αvβ3 is a suitable targeting site for anti-angiogenesis of tumor. We designed and prepared a self-assembling peptide (SAP) with the ability to targeting αvβ3 and self-assembly. SAP formed nanoparticles in solution and transformed into nanofibrous network once specifically binding to integrin αvβ3 on the surface of human umbilical vein endothelial cells (HUVECs). The SAP network stably anchored on HUVECs over 24 h, which consequently resulted in high-efficient inhibition of vascularization. In vitro anti-angiogenesis experiment displayed that the inhibition rate of tube-formation reached 94.9%. In vivo anti-angiogenesis array based on chick chorioallantoic membrane (CAM) model exhibited that the SAP had an inhibition rate up to 63.1%. These results indicated the outstanding anti-angiogenic ability of SAP, potentially for tumor therapy.

Binary transition-metal oxides (BTMOs) with hierarchical micro-nano-structures have attracted great interest as potential anode materials for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical cauliflower-like CoFe2 O4 (cl-CoFe2 O4 ) via a facile room-temperature co-precipitation method followed by post-synthetic annealing. The obtained cauliflower structure is constructed by the assembly of microrods, which themselves are composed of small nanoparticles. Such hierarchical micro-nano-structure can promote fast ion transport and stable electrode-electrolyte interfaces. As a result, the cl-CoFe2 O4 can deliver a high specific capacity (1019.9 mAh g-1 at 0.1 A g-1 ), excellent rate capability (626.0 mAh g-1 at 5 A g-1 ), and good cyclability (675.4 mAh g-1 at 4 A g-1 for over 400 cycles) as an anode material for LIBs. Even at low temperatures of 0 °C and -25 °C, the cl-CoFe2 O4 anode can deliver high capacities of 907.5 and 664.5 mAh g-1 at 100 mA g-1 , respectively, indicating its wide operating temperature. More importantly, the full-cell assembled with a commercial LiFePO4 cathode exhibits a high rate performance (214.2 mAh g-1 at 5000 mA g-1 ) and an impressive cycling performance (612.7 mAh g-1 over 140 cycles at 300 mA g-1 ) in the voltage range of 0.5-3.6 V. Kinetic analysis reveals that the electrochemical performance of cl-CoFe2 O4 is dominated by pseudocapacitive behavior, leading to fast Li+ insertion/extraction and good cycling life.

Herein, we synthesized two isostructural metal–organic frameworks (MOFs) [(CH3)2NH2]6[M6(OBA)6(L1)3(SO4)2]·SO4·x(solvent) (M: Zn for 1, Co for 2, H2OBA = 4,4′-oxybis(benzoic acid), L1 = 4-amino-3,5...

Theoretical investigations have elucidated the mechanism of metal-free electrophilic phosphinative cyclization of alkynes reaction reported by Miura and coworkers. Two competitive mechanisms I and II were explored without or with 2,6-lutidine. Both of I and II involve transformation of P(V) to P(III), electrophilic addition, ring opening and cyclization/cyclization, hydrogen-transfer, and oxidation. The rate-determining step of mechanism I and competitive less-step II is electrophilic [2 + 1] cycloaddition and electrophilic addition via single CP bond formation with activation barrier of 13.5 and 10.6 kcal/mol, respectively. Our calculation results suggested that the cumulative effect of the isomer of 2,6-lutidine and Tf2 O as well as TfO- affects the title reaction to some extent, and simultaneously activates key reaction sites and reverses the polarities of them via the formation of abundant noncovalent interactions to decrease activation barriers of TSs. In addition, the effects of two series substituents on reactivity of phosphine oxide were investigated. Therefore, our study will serve as useful guidance for more efficient metal-free synthesis of organophosphorus compounds mediated by pyridine reagents.

The hydroazidation of alkynes is the most straightforward way to access vinyl azides—versatile building blocks in organic synthesis. We previously realized such a fundamental reaction of terminal a...

The adsorption and separation abilities of gases (including CO2, CH4, N2, and H2) in a series of chiral COFs (CCOFs) were studied using the Grand canonical Monte Carlo (GCMC) method, periodic density functional theory (DFT) (PBE functional) calculations and accurate dispersion corrected double-hybrid DHDF-D3 to explore the potential application of recently synthesized chiral COFs (Han et al., J. Am. Chem. Soc., 2018, 140, 892–895 and Han et al., J. Am. Chem. Soc., 2017, 139, 8693–8697). In contrast to four classical structures (including IRMOF-1, UMCM-1, COF-5, and ZIF-8), CCOF6 shows a better CO2 adsorption capacity at 298 K in a wide range of pressure from 0 to 100 kPa. More importantly, the selectivity of CO2 over N2, CH4 and H2 in CCOF6 is obviously greater than that of other classic porous materials. GCMC simulation demonstrates that the CO2 molecules prefer the smaller B1 channel in CCOF6 at pressure lower than 10 kPa; however, there is no obvious preferential adsorption site in CCOF5. To better understand the mechanism of CO2 adsorption in CCOFs, the interaction energy between CO2 and CCOFs was calculated by the double-hybrid DFT-D3, confirming the preferred adsorption sites in CCOF6 due to the proper narrow channel and the charge transfer from CO2 to CCOF6. Our well established theoretical calculation reveals that CCOF6, with promising CO2 adsorption and selectivity properties, has the potential to be an excellent material for CO2 adsorption and separation.

The Fe-based transition metal oxides are promising anode candidates for lithium storage considering their high specific capacity, low cost, and environmental compatibility. However, the poor electron/ion conductivity and significant volume stress limit their cycle and rate performances. Furthermore, the phenomena of capacity rise and sudden decay for α-Fe2 O3 have appeared in most reports. Here, a uniform micro/nano α-Fe2 O3 nanoaggregate conformably enclosed in an ultrathin N-doped carbon network (denoted as M/N-α-Fe2 O3 @NC) is designed. The M/N porous balls combine the merits of secondary nanoparticles to shorten the Li+ transportation pathways as well as alleviating volume expansion, and primary microballs to stabilize the electrode/electrolyte interface. Furthermore, the ultrathin carbon shell favors fast electron transfer and protects the electrode from electrolyte corrosion. Therefore, the M/N-α-Fe2 O3 @NC electrode delivers an excellent reversible capacity of 901 mA h g-1 with capacity retention up to 94.0 % after 200 cycles at 0.2 A g-1 . Notably, the capacity rise does not happen during cycling. Moreover, the lithium storage mechanism is elucidated by ex situ XRD and HRTEM experiments. It is verified that the reversible phase transformation of α↔γ occurs during the first cycle, whereas only the α-Fe2 O3 phase is reversibly transformed during subsequent cycles. This study offers a simple and scalable strategy for the practical application of high-performance Fe2 O3 electrodes.

It is urgent to explore high-capacity and efficient anode materials for rechargeable lithium-ion batteries. For borophene and phosphorene, two configurations are considered to form a heterojunction: twist angles of 0° (I) and 90° (II). There is a less degree of mismatch and larger formation energy in the formation of a B/P heterojunction, implying that borophene and phosphorene form the stable heterojunction. The heterojunctions of these two configurations demonstrate good conductivity, and the electrons near the Fermi level are mainly provided by borophene. Very importantly, the low energy barrier for interlayer migration of Li is observed in configuration I (0.14eV) and II (0.06 eV), and the migration of Li on the borophene and phosphorene side of the heterojunction still maintains its original energy barrier in bare monolayer. Moreover, the two configurations show the theoretical capacity as high as 738.69 and 721.86 mA h g−1, respectively, which is comparable to bare phosphorene. Furthermore, compared with bare phosphorene, the average voltage is greatly reduced after the formation of heterojunction. Hence, the overall electrochemical properties of the B/P heterojunction have been enhanced by combining the advantages of the individual phosphorene and borophene monolayers, which guarantees the B/P heterojunction as a good candidate for the anode material used in Li-ion batteries.

Owing to low ion/electron conductivity and large volume change, transitional metal dichalcogenides (TMDs) suffer from inferior cycle stability and rate capability when used as the anode of lithium-ion batteries (LIBs). To overcome these disadvantages, amorphous molybdenum sulfide (MoSx ) nanospheres were prepared and coated with an ultrathin carbon layer through a simple one-pot reaction. Combining X-ray photoelectron spectroscopy (XPS) with theoretical calculations, MoSx was confirmed as having a special chain molecular structure with two forms of S bonding (S2- and S22- ), the optimal adsorption sites of Li+ were located at S22- . As a result, the MoSx electrode exhibits superior cycle and rate capacities compared with crystalline 2H-MoS2 (e.g., delivering a high capacity of 612.4 mAh g-1 after 500 cycles at 1 A g-1 ). This is mainly attributed to more exposed active S22- sites for Li storage, more Li+ transfer pathways for improved ion conductivity, and suppressed electrode structure pulverization of MoSx derived from the inherent chain-like molecular structure. Quantitative charge storage analysis further demonstrates the improved pseudocapacitive contribution of amorphous MoSx induced by fast reaction kinetics. Moreover, the morphology contrast after cycling demonstrates the dispersion of active materials is more uniform for MoSx than 2H-MoS2 , suggesting the MoSx can well accommodate the volume stress of the electrode during discharging. Through regulating the molecular structure, this work provides an effective targeted strategy to overcome the intrinsic issues of TMDs for high-performance LIBs.

Metal doped MoS2 monolayer as single atom catalyst (SAC) for CO oxidation has been investigated using spin-polarized density functional theory (DFT) calculations. After carefully screening of several normal non-noble metals, Al doped MoS2 is proven to be the most promising SAC. In Eley-Rideal (ER) mechanism, the energy barrier of the rate-determining step (RDS) is as low as 0.19 eV, which is lower than that of Langmuir-Hinshelwool (LH) mechanism (0.39 eV). It is worth to note that the energy barrier of ER mechanism is lower than most SACs, including those graphene based materials. Very interestingly, in the last step of the ER mechanism, the second CO2 cannot be dissociated spontaneously because of the strong interaction between CO2 and Al-MoS2 with the Ead of −0.78 eV, until another O2 was adsorbed to weaken their interaction resulting in the energy barrier of 0.01 eV. Then the left adsorbed O2 will continue the reaction via ER mechanism. Our results demonstrate that Al-MoS2 is a promising SAC for CO oxidation.

Nanostructured molybdenum disulfide (MoS2) is successfully embedded in the N-doped porous carbon to form micro-sized MoS2/N-C particles via a simple one-pot solution reaction. Yolk, a biomass carbon source with rich nitrogen and oxygen, makes a success to the heteroatom self-doping. The obtained N-doped porous carbon coating layers largely improve the conductivity and electrochemical activity. Moreover, the unique structure of MoS2 nanodots embedded in the porous carbon effectively combines the advantages of nanoscale MoS2 and micron scale N-doped C, which addresses the issues of MoS2 in lithium ion batteries (e.g., poor conductivity, sulfur loss and easy conglomeration). Interestingly, MoS2/N-C composite shows the first discharge/charge capacities of 1002 and 724 mAh g−1 at 0.1 A g−1 and stabilizes around 805 mAh g−1 after 100 cycles. Especially, it still remains at 630 mAh g−1 even under 0.5 A g−1 after 500 cycles, exhibiting excellent lithium ion (Li+) storage and cycle-to-cycle durability. This desired performance of MoS2/N-C is mainly resulted from the unique embedded structure, which effectively improves ion/electron transportation, ensures high sulfur reservation and prevents the conglomeration or accumulation during lithiation/delithiation reaction.

Lithium-ion batteries (LIBs) are one of the most significant energy storage devices applied in power supply facilities. However, a huge number of spent LIBs would bring harmful resource waste and environmental hazards. In this study, a benign hydrometallurgical method using phytic acid as precipitant is proposed to recover useful metallic Mn ions from spent LiMn2 O4 batteries. Besides Mn-based cathodes, this recovery process is also applicable for other commercial batteries. More importantly, for the first time, the as-obtained manganous complex is employed as a nanofiller in a polyethylene oxide matrix to largely improve Li+ conductivity and transference number. As a result, when applied in all-solid-state lithium batteries, high capacity and outstanding cyclic stability are achieved with capacity retention of 86.4 % after 60 cycles at 0.1 C. The recovery of spent lithium batteries not only has benefits for the environment and resources, but also shows great potential application in all-solid-state lithium batteries, which opens up a costless and efficient circulation pathway for clean and reliable energy storage systems.

A novel type of ionic covalent organic framework (ICOF) with a spiroborate linkage has been recently designed and synthesized by Zhang and co-workers (Ionic Covalent Organic Frameworks with Spiroborate Linkage, Angew. Chem. Int. Ed. 2016, 55, 1737-1741). The spiroborate-linked ICOFs exhibit high Brunauer-Emmett-Teller (BET) surface areas and significant amounts of H2 and CH4 uptakes, combined with excellent thermal and chemical stabilities. Inspired by the novel properties of ICOFs, with the aim of gaining better understanding of the structure of such spiroborate-linked ICOFs, a series of potential 3D network configurations of ICOFs connected with tetrahedral [BO4 ]- nodes were proposed, assuming the [BO4 ]- node in spiroborate segments takes a tetrahedral configuration. These ICOFs, in terms of 2D and 3D topology through torsional energy of the [BO4 ]- fragment, pore-size distribution, total energy of the framework, and gas adsorption properties were compared and systematically investigated by density functional theory calculations, molecular mechanics, and well-established Grand canonical Monte Carlo simulations. The results indicate that spiroborate-linked ICOFs are likely a mixture of various topologies. Among these architectures, the five-fold interpenetrating model shows the lowest energy and reasonable gas uptakes, therefore, it is considered to be the most possible structure. More importantly, the five-fold interpenetrating model, showing high CH4 uptakes compared with several classic porous materials, represents a promising CH4 storage material.

A three-fold interpenetrated metal–organic framework [Co2(OBA)4(PTD)·3DMF·CH3CH2OH·5H2O]n (1) has been synthesized by utilizing 4,4′-oxybis(benzoic acid) (H2OBA) as the linker, 6-(pyridin-4-yl)-1,3,5-triazine-2,4-diamine (PTD) as the ligand, and CoCl2·6H2O via solvothermal method. Compound 1 exhibits not only a high uptake capacity for CO2 molecules with an estimated high sorption heat (50.6 kJ mol−1 at zero loading), but also a significant selective adsorption of CO2 over CH4, which may be ascribed to the presence of proper-sized pores with high polarity, amine groups and triazine rings of PTD linker decorating the pores. Meanwhile, the Grand Canonical Monte Carlo (GCMC) simulations of CO2 adsorption of compound 1 demonstrate that CO2 molecules are preferentially adsorbed around the PTD ligands. Furthermore, complex 1 displays a relatively high adsorption capacity of H2 (101.7 cm3 g−1 at 1 bar) under 77 K.

A series of derivatives based on 10,10-dimethyl-5,10-dihydro-pyrido[4,3-b][1,6]naphthyridine–diphenylsulphone (DMDHNP-DPS) named 1a was designed with CH/N and H/CN substitution at the DPS acceptor unit to obtain blue thermally activated delayed fluorescence (TADF) materials. The parent molecule 1a was chosen from our previous report after CH/N substitution at the DMAC donor fragment. The highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) were largely distributed over the DMDHNP donor and DPS acceptor units, respectively, resulting in a slight overlap between the HOMO–LUMO and hence a smaller singlet–triplet energy gap (ΔEST). Steric hindrance caused a large dihedral angle (≈82°–89°) between the plane of the electron-donating DMDHNP unit and the electron-accepting DPS unit in the substituted derivatives. Calculated results indicated that the ΔEST values of H/CN substituted derivatives were smaller than those of the corresponding CH/N derivatives which were favorable for the reverse intersystem crossing (RISC) process from the lowest excited triplet states (T1) to the lowest excited singlet (S1) states and ultimately to the ground state (S0) causing delayed emission. The emission wavelengths (λem) of all the designed molecules were found to be in the range of 397–497 nm. The incorporation of the –N atom or the –CN group at the ortho and meta positions of DPA reduced the transition energies from LUMO → HOMO in the S1 states, resulting in a red-shift. Moreover, the λem values displayed a more substantial bathochromic-shift as the number of –N atoms or –CN groups increased. The two of the designed molecules (1h and 1i) showed sky-blue emission (494 nm and 497 nm), and the four of the investigated compounds (1c, 1d, 1f, and 1g) displayed blue emission (416 nm, 447 nm, 437 nm, and 432 nm, respectively) indicating that these investigated derivatives were efficient sky-blue to blue TADF candidates. Among all the investigated derivatives, the smaller ΔEST values for the designed systems 1f (0.03 eV) and 1g (0.02 eV) and appropriate λem values of 437 nm and 432 nm make them excellent candidates for blue TADF materials. Our theoretical investigation might offer hints for the construction of efficient blue TADF-based organic light emitting diodes (OLEDs) in the future.

A stable, luminescent zinc–organic framework (MOF) [Zn(OBA)2(PTD)·2DMF·2H2O]n (1; H2OBA = 4,4′-oxybis(benzoic acid), PTD = 6-(pyridin-4-yl)-1,3,5-triazine-2,4-diamine) was synthesized using a V-shaped, carboxylate H2OBA ligand containing conjugated π-moieties and a rigidly auxiliary N-rich PTD ligand, which displayed a 3D, three-fold interpenetrated framework with highly thermal and chemical stabilities. Complex 1 exhibited a strong luminescent emission, and could selectively detect Cu2+ and Cr2O72−, making it a potential dual functional chemosensor. Furthermore, the systematic explorations of lanthanide(III) cation encapsulation for compound 1 suggested that Ln3+-doped compounds are good candidates as color-tunable and barcoded materials. Moreover, by soaking this as-synthesized MOF (50 mg) into a 10 mL DMF solution containing 5 × 10−5 mmol Ln3+ ions (Eu3+/Tb3+, 13/7), the white light-emission of the Ln3+-doped compound 1 was realized with the Commission Internationale de L’Eclairage coordinates (0.3095, 0.2945). The quantum yield of this white light-emitting sample is 29%, which is higher than those of most reported doped MOFs with white light-emission. Furthermore, compound 1 exhibited a selective gas capture for CO2 over CH4.

Three metal–organic frameworks, {[Co2(ao0.34btc)(DMF)3]·3DMF}n (1), {(Me2NH2)2[Mn12(OH)4(abtc)6(DMA)6(H2O)6][Mn(H2O)4]·36H2O}n (2), and {[Zn3(abtc)1.5(H2O)2.5(DMA)0.5]·5DMA·2CH3OH}n (3), were successfully designed and synthesized by using H4abtc ligand under solvothermal conditions (H4abtc = 3,3′,5,5′-azobenzenetetracarboxylic acid, DMF = N,N-dimethyformamide, and DMA = N,N-dimethylacetamide). In complex 1, the ao0.34btc4− ligands connect [Co2(CO2)4] second building units (SBUs) to generate a three-dimensional (3D) crystal structure, showing the “PtS”-type topology. The [Mn3OH(CO2)6] SBUs connected by abtc4− produce the 3D “soc”-type cage in complex 2. Complex 3 consists of two categories of [Zn2(CO2)4] SBUs, resulting in the “NbO”-type cage with the assistance of the abtc4− ligands. Magnetic measurements reveal that antiferromagnetic exchange interactions exist in complexes 1 and 2. Besides, the luminescence investigations of complex 3 show its excellent sensing ability toward Fe3+ ions by fluorescence quenching.

All-purpose electrode materials (APEMs), which can be effectively available on not only alkali-ion batteries but also emerging Li metal batteries, are urgently pursued to open up cost-efficient tactics for practical application of energy storage systems (ESSs), but still remain challenging. Herein, the hierarchical porous carbon nanotubes network (NOPCT) with well-tailored nanoarchitecture and high N/O-co-doping content (20.6 at%) is developed to present large-span application on ESSs. As for Li/Na-ion batteries, the NOPCT delivered excellent cycle stability and robust rate performance in a conventional ester-based electrolyte. Moreover, NOPCT also serving as a metal Li host can effectively guide smooth and uniform Li nucleation/growth to enhance the cycle stability of hybrid Li metal anodes. In addition, the NOPCT played an important role in the sustainability of sulfur electrodes, promising the feasibility of shared NOPCT for practical Li-S batteries. First-principle calculations demonstrate that graphitic-N and CO function groups favor for improving electron conductivity while the pyridinic-N and CO function group make sense for improved Li/Na adsorption and affinity through Lewis acid-base interaction, enlightening the interplay between various doped categories on improved electrochemical performance of NOPCT. This work provides profound theoretical and experimental insight into the design and development of APEMs for advanced ESSs.

Although the achievements made for improving the stability of MoS2, active sites-loss resulting from layers stack and structure-collapse still exists in harsh conditions (e.g., super-high current density, low temperature). This is mainly because the current matrixes are lack of chemical anchoring effect and confinement ability for MoS2 growth. Herein, a new concept of “confined-growth MoS2” (noted as c-MoS2) is proposed to successfully prepare MoS2 with long life cycle performance especially in harsh conditions for lithium/sodium-ion batteries (LIBs/SIBs). A unique composite matrix consisted of carbon and carbonnitride TiO2 nanocrystals (TiO2 NCs) is designed to provide an ideal environment for MoS2 growth. The profound investigation on the formation process confirms an “in-situ driving nucleation and growth” mechanism, forming the designed covalent bond and confinement effect between matrix and MoS2. As a result, the capacity of c-MoS2 at 5 A g−1 maintains 450 mAh g−1 for 600 cycles with no fading in LIBs, and reaches more than 220 mAh g−1 for 2000 cycles at 1 A g−1 in SIBs. Especially, super-stable performance at low temperature (0 °C and −25 °C), and rechargeable lithium-ion full battery coupled with LiNiCoMnO2 cathode are achieved. This unique composite matrix and novel concept provide an insight into designing stable two-dimension materials as well as their application in fast charging batteries.

A stable hex-type metal-organic framework (MOF, WMOF-1) was constructed by nano-sized [MnII18 ] metallamacrocycle secondary building unit, being the one with the highest nuclearity of manganese wheel-like node in the microporous MOF. WMOF-1 displays an effective gas adsorption and the antiferromagnetic behavior.

The mechanisms of the synthesis of 2-substituted-3-(1H-indol-3-yl)-isoindolin-1-one derivatives have been investigated theoretically under unassisted, self-assisted, and water-assisted conditions. Being different from previously proposed catalyst-free by Hu et al., our results show that the title mechanism can be altered and accelerated by solvent and substrate 2. Two types of mechanisms have been developed by DFT calculations differ in the reaction sequence of substrates 1 with 3 (M1) or 2 (M2) followed by 2 (M1) or 3 (M2), and water-assisted M1 is the most favored one. It was found that the nucleophilicity of substrate 3 is stronger than that of 2. Our calculations suggest that the water-assisted pathway in M1 is the most favorable case, which undergoes nucleophilic addition and H-shift, C-N bond formation and water elimination, and intramolecular cyclization and water elimination. The rate-determining step is the nucleophilic attack process. Moreover, we also explored the effect of nucleophilic attack of the nitrogen of (4-methoxyphenyl)methanamine on hydroxyl or carbonyl group carbon of phthalaldehydic acid on the activation energy. More importantly, we found that water molecules play a critical role in the whole reaction, not only act as solvent but also as an efficient catalyst, proton shuttle, and stabilizer to stabilize the structures of transition states and intermediates via π···H-O, O···H-N, O···H-C, and O···H-O interactions. The origin of the different reactivity of M1 and M2 is ascribed to the pivotal noncovalent interactions exist between catalyst (water and substrate 2) and reactants. © 2018 Wiley Periodicals, Inc.

The mechanism of N-Bromosuccinimide (NBS) promoted synthesis of imidazo[1,2-a]pyridine in water as well as the effective activation modes of NBS was investigated by Density Functional Theory (DFT) calculations. Two main mechanisms that differ in the reaction sequence of substrate were explored: styrene with NBS then followed by 2-aminopyridine (M1) or simultaneously with NBS and 2-aminopyridine (M2), and water-assisted M2 is the more favored one. We found that the adding sequence of 2-aminopyridine affects profoundly on the title reaction. Moreover, upon the assistance of water and NBS, the preferential mechanistic scenario involves three major processes: nucleophilic addition, stepwise H-shift and intramolecular cyclization, three-step deprotonation, rather than a classical bromonium ion species. Specifically, the cooperative interaction of NBS and water plays a critical role in the title reaction. Water acts as solvent, reactant, anchoring, stabilizer, and catalyst. NBS promotes the above three processes by the effective forms of Br+ /Br- , succinimide, and its ethanol isomer. Furthermore, noncovalent interactions between catalysts and substrates are responsible for the different reactive activities of M1 and M2. Our results indicate that simultaneous adding of all reactants is recommended toward economical synthesis. © 2018 Wiley Periodicals, Inc.

Cerebral amyloid β-peptide (Aβ) accumulation resulting from an imbalance between Aβ production and clearance is one of the most important causes in the formation of Alzheimer’s disease (AD). In order to preserve the maintenance of Aβ homeostasis and have a notable AD therapy, achieving a method to clear up Aβ plaques becomes an emerging task. Herein, we describe a self-destructive nanosweeper based on multifunctional peptide-polymers that is capable of capturing and clearing Aβ for the effective treatment of AD. The nanosweeper recognize and bind Aβ via co-assembly through hydrogen bonding interactions. The Aβ-loaded nanosweeper enters cells and upregulates autophagy thus promoting the degradation of Aβ. As a result, the nanosweeper decreases the cytotoxicity of Aβ and rescues memory deficits of AD transgenic mice. We believe that this resourceful and synergistic approach has valuable potential as an AD treatment strategy., Cerebral amyloid β-peptide accumulation is a causative factor in Alzheimer’s Disease. Here the authors design a 'nanosweeper' that binds amyloid β-peptide and induces autophagy to clear the accumulated plagues.

A new hexadecahedron assembled by core-shell CoS2 particles@N-doped carbon (CoS2 @NCH) is prepared successfully through the self-templating method. The CoS2 @NCH hybrid electrode delivers a high lithium-storage capacity of 778 mA h g-1 after 1000 cycles at a high current density of 1 A g-1 , which is the longest cycle lifespan among the reported CoS2 anode materials in lithium-ion batteries. Furthermore, the CoS2 @NCH hybrid electrode shows excellent rate capability with a discharge capacity of 220 mA h g-1 at an extremely high current density of 20 A g-1 , and a charge capacity of 649 mA h g-1 is restored upon returning the current density back to 2 A g-1 . The superior performance is attributed to the unique construction of CoS2 @NCH. The N-doped interconnected porous carbon shells form highly conductive skeletons for quick electron transfer and prevent the electrode from collapsing. Moreover, the porous characteristic of the materials plays a key role: as some effective channels, the mesopores on the porous carbon shells provide greater access for lithium, and the mesopores derived from the particle interspace enables the complete immersion of the electrodes in electrolyte, which alleviates the volume expansion and ensures the integrity of the electrode. In addition, the nanosized CoS2 particles, which shorten the ion-transport path and provide extra electroactive sites, also improve the reaction kinetics.

Recently, Li−S batteries with a high theoretical specific energy have attracted significant attention. However, their practical application is still seriously hindered by the shuttling effect of lithium polysulfides (LiPSs) in the Li−S batteries system. Introducing anchoring materials into the cathode or separator, which can strongly attract LiPSs because of advisable binding energies, has been demonstrated as an effective strategy to alleviate the shuttling effect for achieving the excellent cycling performance of Li−S batteries. In this work, the complete mechanistic understanding of the interaction between non-metallic monolayer materials (N-MMLMs, including Graphene, BN, C2N and C3N4) and LiPSs is given in detail with the aid of density functional theory. The calculation results show that N-MMLM can combine the chemical interaction and the physical entrapment of sulfur species to suppress the shuttling effect. C3N4 and C2N are predicted to trap LiPSs via stronger interfacial interaction and alleviate the interactions between LiPSs and solvents as well as the consequent dissolution. The strong anchoring effect of C3N4/C2N comes from the bonding of Li−N/C−S and charge transfer. Further charge transfer study reveals that the C3N4/C2N can serve as an electrocatalyst, which effectively accelerates the kinetics of LiPSs redox reactions.

Tumor metastasis as the most common reason of death from cancer has always been a great challenge in both clinical and scientific research, where angiogenesis plays a necessary role. Herein, we report an extracellularly transformable nanomaterial for in situ construction of defensive networks on interaction with vascular endothelial growth factor (VEGF) for anti-angiogenic therapy of tumor. The fibrous networks exhibit transformation-enhanced accumulation and retention (TEAR) effects (over 72 h), and bind and intercept cell-secreted VEGF over particulate and molecular anti-angiogenic agents with high efficiency, leading to anti-angiogenesis. This study demonstrates that angiogenesis is positively related to tumor growth as well as tumor metastasis; the anti-angiogenic therapy inhibits tumor metastasis with an inhibition rate of 65.9%. In addition, this extracellular strategy of transformation may be utilized to bind huge amounts of cell-secreted biomolecules/factors or receptors on cell surfaces and inhibit their functionalities for cancer therapy.

In this article, an effective strategy (viz., constructing multiple heterointerfaces) is proposed to develop superior electrode materials for sodium-ion battery (SIB), which is the most promising alternative to market-dominant lithium-ion battery for stationary energy storage. In the as-prepared heterogeneous-SnO2/Se/graphene (h-SSG) composite, there exists multiple phase interfaces, including heterointerfaces between tetragonal and orthorhombic SnO2 (t-/o-SnO2) in the heterogeneous SnO2 nanojunctions and two phase interfaces between t/o-SnO2 and amorphous Se. These multiple phase interfaces promise the much improved Na storage properties of h-SSG when compared to four controls without such multiple heterointerfaces because the multiple built-in electric fields at the heterointerfaces can significantly boost the surface reaction kinetics and facilitate charge transport as demonstrated by kinetics analyses, theoretical calculations and contrastive electrochemical tests. Moreover, h-SSG also exhibits superior Na-ion full cell performance when coupled with a high-voltage Na3V2(PO4)2O2F cathode. In view of the universality of the heterointerface-based enhancement effect on surface reaction and charge transport kinetics and the facile preparation procedures, the present strategy should be universal to develop other superior electrode materials for high-performance SIBs and other batteries for future energy storage applications.

Two neutral/cationic metal–organic frameworks (MOFs), [Mn3(μ3-OH)(in)4(CH3COO)(H2O)]·H2O (Mn-Ac) and [Co3(μ3-OH)(in)4(DMA)2(H2O)]ClO4·DMA·3H2O (Co-DMA), based on triangular secondary building units (SBUs) MII3(OH)(O2CR)4L3 (M = Mn/Co, R = linker group, and L = coligand) with the same hex topology are successfully constructed using an isonicotinic acid (Hin) ligand, and their framework charges are controlled by the synergistic effects of counterions, solvent and metal centers. Three MnII/CoII ions were blocked by carboxylates from Hin and μ3-OH, forming triangular cationic [MII3(OH)(O2C)4]+ units. Then in Mn-Ac, the CH3COO− counterion of the manganese(II) salt is used as a coligand, and it could be preemptively coordinated with the metal to obtain the neutral SBU. In addition, Mn-Ac possesses a neutral framework with low symmetry and trapezium-shaped channels with small effective pore sizes. When using Co(ClO4)2 instead of Mn(CH3COO)2 in compound Co-DMA, the solvent DMA molecules proactively blocked the remaining cobalt(II) sites of [CoII3(OH)(O2C)4]+, forming cationic SBUs. Therefore, the cationic framework Co-DMA was obtained, which shows open square-shaped channels. The desolvated framework of Co-DMA displays a Langmuir surface area of 839 m2 g−1 and more effective sorption capacities for N2, CO2 and H2 than those of Mn-Ac, which is probably because the cationic Co-DMA has a larger effective aperture and stability than the neutral Mn-Ac. Magnetic studies show dominant antiferromagnetic behaviours for both Mn-Ac and Co-DMA.

Micro–nano structures (M–N) are thought to be one of the best systems for conversion reaction-based anode materials used in lithium-ion batteries because they combine the advantages of nanometer-sized building blocks and micrometer-sized assemblies. However, some drawbacks of most M–N materials, particularly the existence of unactivated materials caused by low electronic conductivity, poor redox kinetics and insufficient electrolyte penetration, hamper their widespread application to some extent. In this work, these issues were addressed by the rational design of an M–N structure containing hollow carbon nanofibers (HCNFs). Perfectly shaped and hierarchical MnO spheres were grown in situ on the HCNFs (MnO/HCNFs), forming a cherry-like morphology. Of particular note is the role of the HCNFs, which act as electrical “highways” through which electrons can travel very quickly to the inside of the hierarchical MnO microspheres without obstruction. As a result, electrochemical tests demonstrated that the MnO/HCNFs exhibited much improved Li-storage properties in terms of high reversible capacity with long-term cycle life (1093.4/987.6 mA h g−1 after 300/800 cycles at 200/2000 mA g−1) and superior rate capability (206.3 mA h g−1 at 6.4 A g−1) in comparison to conventional M–N MnO spheres without HCNFs. Moreover, the realization of good electrochemical performance without nanostructuring in complex metal oxides expands the scope of the HCNF-inserted M–N structure for other materials used in energy storage.

Phosgene, one of the common chemicals in many industry areas, is extremely harmful to human and the environment. Thus, it is necessary to design the advanced materials to detect or remove phosgene effectively. In fact, detection or adsorption of some small gas molecules are not the most difficult to actualize. Whereas, one of the primary challenges is the gas molecules desorption from the adsorbent for the purpose of recycling of substrate materials since the small gas molecules interacts strongly with the substrates. In this work, the interaction between the phosgene molecule and pristine or Mn-doped graphene sheets with different electric field and charge state are investigated by using first-principles simulations. Our results show that the adsorption energy of phosgene on Mn-doped graphene is dramatically weakened by applying an external negative electric field but is obviously enhanced by introducing a positive electric field. These processes can be easily controlled by transform the direction of the electric field. Thus, introducing an external electric field or charge in the system may be an excellent method to control the phosgene molecule adsorption and desorption on Mn-doped graphene sheet. All energy needed is just a small quantity of electricity, which satisfies well the requirement of green chemistry and sustainable development. The mechanism and reason of reversible adsorption/desorption is also revealed in terms of energy, charge distribution and orbital analysis. Such spontaneous adsorption or desorption makes Mn-doped graphene to be used as an excellent reusable scavenger of phosgene.

In recent years, various transformable nanoparticles (NPs) were successfully prepared and widely utilized for biomedical applications. The sizes, surface charges or morphologies of transformable NPs would affect their behavior in physiological/pathological conditions including circulation, penetration, accumulation and retention etc. The other way round, the NPs could be precisely modulated in the specific physiological/pathological condition for precision theranostics of diseases. Herein, we summarized recent advances of transformable NPs for disease diagnostics and therapy. In this review, the transformation of NPs was divided into three groups including changes in size, surface charge and morphology, which was induced by internal stimuli, such as pH, enzyme, receptor or external stimuli, such as light, temperature etc. Moreover, we focused on the characterization of structural transformation in vivo , as well as the transformation-induced biological effects for theranostics of disease.

Silver-mediated hydroazidation of unactivated alkynes has been developed as a new method for the synthesis of vinyl azides. Density functional theory calculations toward this reaction reveal that terminal alkynes with TMS-N3 participated hydroazidation proceed through HN3 formation, deprotonation and silver acetylides formation, nucleophilic addition, and protonation of terminal carbon by AgHCO3. It is also found that water molecules and activation modes of Ag (I) have a significant influence on the title reaction mechanism. Initially, catalyst Ag2CO3 coordinates preferentially with internal N atom of TMS–N3 to assist water as hydrogen source and proton-shuttle in facilitating HN3 formation. Then, the regioselective anti-addition of HN3 to triple bond of active silver-acetylide or ethynyl carbinols affords product vinyl azide via Ag–C σ-bond activation or Ag…C π-coordination activation modes, and the former one is more favorable. The origin of the difference regioselectivity is ascribed to the electronic and orbital effects of the reactive sites. Moreover, Ag2CO3 is the critical catalyst, acting as activator, base, and stabilizer to promote the HN3 and vinyl azide formation. Water molecule plays an important role as proton shuttle to promote HN3 and key active silver acetylides formation, thus improving the yield of product. © 2017 Wiley Periodicals, Inc.

In this work, oxygen-deficient anatase TiO2 nanosheets (A-TiO2-x NSs) are proposed as a substrate to improve the electrochemical properties of sulfur electrodes for lithium-sulfur (Li-S) batteries. The A-TiO2-x NSs are prepared by partly reducing pristine TiO2 nanosheets (A-TiO2 NSs) in NaBH4 solution. With some oxygen vacancies on the surface of the TiO2 nanosheets, A-TiO2-x NSs not only promote electronic transfer, but also act as more effective polysulfide reservoirs to minimize the dissolution of lithium polysulfides (LiPSs) than the A-TiO2 NSs control. Hence, upon utilization as modifiers for cathodes of Li-S batteries, the A-TiO2-x NSs-modified sulfur (A-TiO2-x NSs-S) cathode exhibits a higher reversible specific capacity and greater cycling performance and rate capability than the A-TiO2 NSs-modified one (A-TiO2 NSs-S). For example, A-TiO2-x NSs-S delivers an initial specific capacity of 1277.1 mAh g-1 at 0.1 C and maintains a stable Coulombic efficiency of approximately 99.2 % after the first five cycles; these values are higher than those of 997.3 mAh g-1 and around 96.7 %, respectively, for A-TiO2 NSs-S. The enhanced electrochemical properties of the A-TiO2-x NSs-S cathode can be ascribed mainly to the more effective adsorption of dissolvable and diffused LiPSs by the oxygen vacancies. Therefore, utilization of the structure of oxygen vacancies in Li-S batteries demonstrates great prospects for practical application.

A novel type of porous organic frameworks, based on Mg-porphyrin, with diamond-like topology, named POF-Mgs is computationally designed, and the gas uptakes of CO2 , H2 , N2 , and H2 O in POF-Mgs are investigated by Grand canonical Monte Carlo simulations based on first-principles derived force fields (FF). The FF, which describes the interactions between POF-Mgs and gases, are fitted by dispersion corrected double-hybrid density functional theory, B2PLYP-D3. The good agreement between the obtained FF and the first-principle energies data confirms the reliability of the FF. Furthermore our simulation shows the presence of a small amount of H2 O (≤ 0.01 kPa) does not much affect the adsorption quantity of CO2 , but the presence of higher partial pressure of H2 O (≥ 0.1 kPa) results in the CO2 adsorption decrease significantly. The good performance of POF-Mgs in the simulation inspires us to design novel porous materials experimentally for gas adsorption and purification. © 2017 Wiley Periodicals, Inc.

Bimetallic transition-metal oxides, which exhibit superior electrochemical properties compared with pristine single-metal oxides, have recently become a topic of significant research interest for applications in lithium-ion batteries (LIBs). Herein, we report a simple and scalable electrospinning method to synthesize porous CoTiO3 nanofibers as the precursor for nanostructured bimetallic transition-metal oxides formed electrochemically in situ. This strategy ensures uniform mixing and perfect contact between two constituent transition-metal oxides during the lithiation/delithiation process. Furthermore, CoTiO3 nanofibers based on ultrafine CoTiO3 nanocrystals are interconnected to form a nano/microstructured 3D network, which ensures the high stability of the in situ formed structure composed of bimetallic transition-metal oxides, and also fast ion/electron transfer and electrolyte penetration into the electrode. Electrochemical measurements revealed the excellent lithium storage (647 mAh g-1 at 0.1 Ag-1 ) and retention properties (600 mAh g-1 at 1 Ag-1 after 1200 cycles) of the CoO/TiO2 electrode. Moreover, the electrochemical reaction mechanism was explored by using ex situ X-ray photoelectric spectroscopy and cyclic voltammetry tests, which confirmed the two-phase reaction processes in the electrodes. These results clearly validate the potential of CoTiO3 with a unique nano/microstructured morphology as the precursor for a bimetallic transition-metal oxide for use as the anode material for long-life LIBs.

To explore the adsorption and separation properties of CO2 in a novel material consisting of a series of polyoxometalates (POMs) impregnated within supramolecular porous catenane (shorted as SPC), grand canonical Monte Carlo (GCMC) simulations and ab initio calculations were used. GCMC simulations showed this impregnation can enhance CO2 /CH4 (or CO2 /N2 ) selectivity almost 30 times compared to the bare SPC due to the strong interaction of CO2 with the nPOMs@SPC structures. And, the loading of CO2 inhibits the adsorption of CH4 (or N2 ) as CO2 occupying the preferred adsorption sites. Furthermore, the effect of number, mass, and volume of POMs inserted in SPC on CO2 /CH4 (or CO2 /N2 ) selectivity over large pressure range was investigated in detail. Additionally, the accurate ab initio calculations further confirmed our GCMC simulations. As a result, the proposed nPOMs@SPC structures are promising candidates for CO2 /N2 and CO2 /CH4 separations. © 2017 Wiley Periodicals, Inc.

Although the composite of metal oxide and porous carbon has been confirmed as an effective material to chemically adsorb polysulfides, the low conductivity of the metal oxide results in the need for extra pathways for the diffusion of polysulfides from adsorption sites to redox-active sites. This process results in sluggish reaction kinetics and escaped polysulfides. In this work, a Gerber tree-like interlayer with multiple components was designed to fully mediate the electrochemical conversion of Li–S batteries and shorten the diffusion distance of polysulfides in the composite. The branches of the interlayer contained TiO2 and Co3O4 nanocrystals embedded into N-doped porous carbon, while the fruit was catalytic metal cobalt. The two co-existing chemical adsorbents ensure the restriction of polysulfides through S–Ti–O bonding and Lewis acid–base interaction. Moreover, the metal Co catalyzes the transformation of adsorbed polysulfides into low-order ones, which largely shortens the diffusion pathway, improving the reaction kinetics and preventing the migration of polysulfides. The cell with the interlayer exhibited outstanding electrochemical performance. After 100 cycles, a reversible capacity of 968 mA h g−1 was maintained at 0.1C with a stable capacity retention of 85%. Even at the current rate of 1C, the cell delivered a capacity of 684.5 mA h g−1 after 300 cycles.

Recently, room temperature sodium ion batteries (SIBs) have attracted considerable attention as one of the promising candidates to replace lithium ion batteries. Nevertheless, achieving high capacity and cycling stability remains a great challenge for the electrode materials of SIBs. Compared to the traditional inorganic electrode materials, organic ones should be more attractive because of their easier sodium (Na)-transport accessibility as well as their diversities of organic skeleton and functional groups. In this work, a new carboxyl-based organic, sodium trimesic (Na3TM), is proposed for the first time as an anode material for SIBs, and its Na-storage properties are significantly enhanced by constructing three-dimensional conductive networks of carbon nanotubes (CNT-NWs) in the Na3TM microparticles. In comparison to the pure Na3TM exhibiting almost inactive Na storage, the prepared CNT-NWs@Na3TM composite delivers a reversible capacity of 214.6 mA h g−1 at 0.1 A g−1, and exhibits excellent rate performance with the specific capacities of 149 and 87.5 mA h g−1 at 1 and 10 A g−1, respectively. The CNT-NWs@Na3TM also exhibit good cycling performance. More importantly, the Na-storage mechanism of CNT-NWs@Na3TM was ascertained using several ex situ technologies of Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and 23Na solid-state nuclear magnetic resonance spectroscopy. It is discovered that the two Na uptake/release processes were reversible during cycling and contributed to the Na-storage capacity except for the 1st sodiation process with a three Na uptake.

The reaction mechanism of (E)-methyl 3-(2-aminophenyl)acrylate (A) with phenylisothiocyanate (B) as well as the vital roles of substrate A and solvent water were investigated under unassisted, water-assisted, substrate A-assisted, and water-A-assisted conditions. The reaction proceeds with four processes via nucleophilic addition, deprotonation and protonation, intramolecular cyclization with hydrogen transfer, and keto-enol tautomerization. According to the different H-shift mode, two possible types of H-shift P1 and P2 are carefully investigated to identify the most preferred pathway, differing in the NH2 group deprotonation and CH group of A protonation processes. It is found that substrate A and water not only act as reactant and solvent, but also as catalyst, proton shuttle, and stabilizer in effectively lowering the energy barrier. Therefore, the results demonstrate that the strong donating and accepting ability of NH2 group on A and the presence of bulk water are the keys to the title reaction proceed. © 2016 Wiley Periodicals, Inc.

A dissolution–recrystallization method was developed to prepare flexible paper electrodes constructed of Zn2GeO4 nanofibers anchored with amorphous carbon (ZGO/C-P) for high energy and power Li-ion batteries. The ZGO/C-P exhibits superior long-term cycle stability (up to 2000 cycles at 1 A g−1) and excellent rate capability.

LiPO3, one of the compounds from the Li2O–P2O5 binary phase diagram, is successfully coated on LiNi0.5Mn1.5O4 particles as a bifunctional layer with respect to its good ionic conductivity and chemical passivation properties. The coating layer with a thickness of 1 nm is identified by X-ray diffraction (XRD) and high resolution transition electron microscopy (TEM). Fourier transform-infrared spectrometer (FT-IR) and Raman spectra reveal that LiPO3 coated LiNi0.5Mn1.5O4 (LiPO3/LiNi0.5Mn1.5O4) possesses a cubic spinel structure with a space group of Fdm. The electrochemical properties of synthesized materials are evaluated in both Li ion half cells and full cells. LiPO3/LiNi0.5Mn1.5O4 exhibits significantly enhanced rate performance and superior cyclability compared with non-coated LiNi0.5Mn1.5O4. Impedance analysis indicates that the LiPO3 coating dramatically reduces the LiPO3/LiNi0.5Mn1.5O4 cell impedance, especially the resistances of the lithium ion migration compared with non-coated LiNi0.5Mn1.5O4. In addition, the LiPO3 coating can effectively act as a passivation layer to minimize electrolyte–electrode interface side reactions and thus improve the long-term cyclability.

We have designed three dimensional conjugated three- and four-armed molecules for organic solar cells, featuring a bithiophene donor (DF) fragment connected to a pyridine-thiadiazole acceptor fragment (AF) via an ethyne π-spacer (Ps) as the arms, which are linked to different central core atoms (N, B, C and Si atoms) based on two topologies, “core-D–π–A” (molecules are named N3-Mol, B3-Mol, Si4-Mol and C4-Mol) and “core-A–π–D” (molecules are named N3-RMol, B3-RMol, Si4-RMol and C4-RMol). A combination of density functional theory (DFT) and time-dependent-DFT (TD-DFT) approaches is applied to understand the effect of different central cores on the optical, electronic and charge transport properties of the two topologies. The “core-A–π–D” type molecules display smaller Eg values than those of the “core-D–π–A” type molecules. Therefore, the “core-A–π–D” type molecules show a significant red shift in λmax compared to the “core-D–π–A” type molecules. The molecules C4-RMol, Si4-RMol, B3-RMol and N3-RMol show red shifts of 59, 14, 28 and 39 nm in λmax as compared to C4-Mol, Si4-Mol, B3-Mol and N3-Mol, respectively. Three-armed N3-Mol and N3-RMol display the largest λmax of the designed molecules. Interestingly, B3-RMol and C4-RMol show more or less same λmax values. However, B and Si cores also show more intense absorption bands than N and C cores, respectively. Both the reorganization energy and mobility results reveal that the four-armed molecules show higher charge transport rates than the three-armed molecules because of their better dimensionality. N3-RMol exhibits μe and μh mobilities of up to 2.8 × 10−2 cm2 V−1 s−1 and 3.3 × 10−2 cm2 V−1 s−1 respectively while C4-RMol shows higher μe and μh mobilities of up to 0.163 cm2 V−1 s−1 and 4.14 × 10−2 cm2 V−1 s−1 respectively in the crystalline state, which have been predicted using the P21/c space group. Thus, the comparative analysis of the designed molecules reveals that the “core-A–π–D” topology with the substitution of N and C cores results in molecules which exhibit a narrow Eg, broad and intense absorptions and an anisotropic high charge carrier mobility in the crystalline phase, which is associated with low reorganization energies for organic solar cells.