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All solid-state batteries (ASSBs) are regarded as promising energy storage batteries with high energy density and high safety. The polyethylene oxide (PEO)-based electrolyte with succinonitrile (SN) has attracted critical attention for its high ionic conductivity at room temperature. However, SN can react with Li metal to result in an unstable interface between electrolyte and electrode, which deteriorates the electrochemical performance. In this work, zeolitic imidazolate framework-67 (ZIF-67) is used as a filler to construct composite electrolytes and solve the aforementioned instability issue. The composite electrolyte shows nonflammability, high processability, and a competitive ionic conductivity of 2.78 * 10

Modifying separator with metal oxides has been considered as a strong strategy to inhibit the shuttling of soluble polysulfide in the lithium-sulfur battery (Li-S battery). Manganese dioxide (MnO2), one kind of transition metal oxide, is widely applied to decorate the PP (Polypropylene) separator. However, the fabrication by physical coating is always multistep and complicated. Here, we design a simple and fast method to chemically decorate separator. Based on the oxidizing property of acidic KMnO4 solution, the PP separator was oxidized and an ultrathin self-assembled MnO2 layer was directly constructed on one side of separator, by immersing in acidic KMnO4 solution for only 1 h. The self-assembled MnO2 layer has the synergistic effect of adsorption and catalytic conversion on polysulfides, which can effectively inhibit the shuttle effect. It can also help battery to maintain excellent electrochemical kinetics in the electrochemical cycle and maintain the effective recycling of active substances. As a result, the shuttling of polysulfide is greatly prohibited by this novel functional separator, and cycling stability is outstandingly improved, with a low-capacity decaying of 0.058% after 500 cycles at 0.5C. The rapid and simple modification method proposed in this study has a certain reference value for the future large-scale application of lithium-sulfur battery.

As a secondary Li-ion battery with high energy density, lithium-sulfur (Li-S) batteries possess high potential development prospects. One of the important ingredients to improve the safety and energy density in Li-S batteries is the solid-state electrolyte. However, the poor ionic conductivity largely limits its application for the commercial market. At present, the gel electrolyte prepared by combining the electrolyte or ionic liquid with the all-solid electrolyte is an effective method to solve the low ion conductivity of the solid electrolyte. We present a cross-linked gel polymer electrolyte with fluoroethylene carbonate (FEC) as a solid electrolyte interface (SEI) film formed for Li-S quasi-solid-state batteries, which can be simply synthesized without initiators. This gel polymer electrolyte with FEC as an additive (GPE@FEC) possesses high ionic conductivity (0.830 × 10-3 S/cm at 25 °C and 1.577 × 10-3 S/cm at 85 °C) and extremely high Li-ion transference number (tLi+ = 0.674). In addition, the strong ability toward anchoring polysulfides resulting in the high electrochemical performance of Li-S batteries was confirmed in GPE@FEC by the diffusion experiment, X-ray photoelectron spectroscopy analysis (XPS), and scanning electron microscopy (SEM) mapping of the S element. Such a high ion conductivity (IC) gel polymer electrolyte enables a competitive specific capacity of 940 mAh/g at 0.2C and supreme cycling performance for 180 cycles at 0.5C, which is far beyond that of conventional poly(ethylene oxide)-based quasi-solid-state Li-S batteries.

Serious shuttle effect and sluggish conversion kinetics of lithium polysulfides (LiPSs) have a massive impact on obstructing the practical application of lithium-sulfur (Li–S) batteries. To address such issues, Fe-Nx sites enriched microporous nanoflowers planted with tangled bamboo-like carbon nanotubes (Fe-Nx-C/Fe3C-CNTs NFs) are found to be effective catalytic mediators with strong anchoring capabilities for LiPSs. The bamboo-like carbon nanotubes catalyzed by Fe3C/Fe entangled each other to form a conductive network, which encloses a flower-like microporous carbon core with embedded well-dispersed Fe-Nx active sites. As expected, electrons smoothly transfer along the dense conductive bamboo-like carbon network while the flower-like carbon core consisting of micropores induces the homogeneous distribution of tiny sulfur and favors the lithium ions migration with all directions. Meanwhile, Fe-Nx sites strongly trap long-chain LiPSs with chemical anchoring, and catalyze the redox conversion of LiPSs. Due to the aforementioned synergistic effects, the S@Fe-Nx-C/Fe3C-CNTs NFs cathode exhibited a remarkable specific capacity (635 mAh gs−1) at 3 C and a favorable capacity decay with 0.04% per cycle even after 400 cycles at 1 C.

The flow in a liquid falling film is predominantly laminar, and the liquid-side mass transfer is limited by molecular diffusion. The effective way to enhance the mass transfer is to improve the liquid film flow behavior. The falling film behaviors of water, ethanol and ethylene glycol in nine different wavy microchannels were simulated by Computational Fluid Dynamics. The simulation results show that the falling film thickness exhibits a waveform distribution resulting in a resonance phenomenon along the wavy microchannel. The fluctuation of liquid film surface increases the gas–liquid interface area, and the internal eddy flow inside the liquid film also improves the turbulence of liquid film, the gas–liquid mass transfer in falling film microchannels is intensified. Compared with flat microchannel, the CO2 absorption efficiency in water in the wavy microchannel is improved over 41%. Prediction models of liquid film amplitude and average liquid film thickness were established respectively.

Metal–organic frameworks (MOFs) and covalent–organic frameworks (COFs) are promising precursors for preparing high-performance carbonaceous materials for capacitive deionization (CDI). However, the...

Mesoporous silica nanoparticles (MSNs) exhibit significant advantages for efficient drug/gene delivery but it is hard for simple MSNs to deliver the loaded drug to the target sites of disease. Considering that there are some well-known pH differences in the body, it is a useful strategy to modify the exterior surface of MSNs with stimuli-responsive gatekeepers to realize open–close transformation of their mesopores. In this work, multifunctional pH-sensitive MSNs were designed with mixed polymeric coatings, that is, poly(ethylene glycol) (PEG) as a dispersity-enhancer and poly(2-(pentamethyleneimino)ethyl methacrylate) (PPEMA) as an ultra-pH-sensitive gatekeeper. Enhanced dispersity, high drug loading capacity, long-circulation time, pH-triggered targeting, and better cellular uptake of the multifunctional MSNs make them potential candidates for pH-sensitive drug delivery such as tumor therapy.

Separator modification with metal oxide and carbon composite recently has become a potential and competitive way to confine polysulfide diffusion and mitigate the shuttling effect. However, other modification methods also have an impact on the stability of the modified layer and the enhancement of electrochemical performance. Herein, we first design a novel bifunctional separator combined with one self-assembled FeOOH layer via a chemical way and one conductive g-C3N4/KB layer by physical coating. Different from directly coating the metal oxide and carbon composite on the separator, the self-assembled FeOOH layer is firmly formed on the PP separator, which enables the chemical capture of the soluble polysulfide and prohibit the shuttling effect. Then, the coated g-C3N4/KB layer is further introduced to greatly enhance the transportation of lithium ions and physically confine the migration of intermediates. As a result, the battery with this bifunctional separator (G-SFO) achieves outstanding rate capacities (1000, 901, and 802 mA h/g at 0.5, 1, and 2 C). After 900 cycles at 1 C, it also shows excellent long cycle performance, with relatively low fading (0.055%). This original fabrication will present a new and feasible strategy for fabricating a bifunctional separator with metal oxide and carbon material.

Energy storage devices are indispensable for supporting human activities; thus, producing sustainable environmental energy is a current focus of attention. Lithium–sulfur batteries (Li–S batteries)...

The increased application of layered oxide (LiCoO2) lithium ion batteries (LIBs) for electronic products will result in lots of spent layered cathodes in the near future. Furthermore, the explorati...

Lithium-sulfur battery, one of the most prominent and widely studied batteries, takes sulfur as the cathode which has rich reserves in the earth. It has the characteristics of high energy density, high theoretical specific capacity, affordable cost, and environment-friendly. Although this system has many advantages, it has many essential shortcomings, such as the non-conductivity of active materials and discharge intermediates, shuttle effect, the volume effect of the sulfur cathode, and the dendritic growth of lithium. In this paper, we summarize the solutions and related research of cathode materials in the lithium-sulfur battery from three aspects: the improvement of conductivity, the alleviation of the shuttle effect, and the use of Li2S cathode. And put forward the suggestions and prospects for future improvement methods.

Biomass in nature has diverse microstructures and abundant chemical compositions. There has been a surge of interest in biomass-derived carbon materials due to their adjustable physical and chemical properties, strong chemisorption, environmental friendliness, and low cost. In recent years, research on biomass-derived carbon in energy storage devices, especially lithium batteries, has emerged endlessly. This paper introduces the application of different types of biomass in the host and separator of lithium-sulfur batteries. These biomass carbons have their characteristics in structure, composition, and design. In-depth discussion of the actual impact of these characteristics on battery performance. According to the actual industrial application conditions, the practical problems faced by lithium-sulfur batteries are emphasized, and the future application prospects of bio-derived carbon materials are discussed.

In order to concentrate the diluted sulfuric acid from the titanium dioxide (TiO2) production of sulphate process, a new concentration process was proposed by coupling chemical dehydration and multi-effect evaporation. The ferrous sulfate monohydrate (FeSO4·H2O), as the dehydrant, was added to the diluted sulfuric acid to form ferrous sulfate heptahydrate (FeSO4·7H2O) according to the H2SO4-FeSO4-H2O phase diagrams, which partially removes the water. This process was named as Chemical Dehydration Process. The residual water was further removed by two-effect evaporation and finally 70 wt% sulfuric acid was obtained. The FeSO4·H2O can be regenerated through drying and dehydration of FeSO4·7H2O. The results show that FeSO4·H2O is the most suitable dehydrant, the optimal reaction time of chemical dehydration process is 30 min, and low temperature is favorable for the dehydration reaction. 45.17% of the entire removed water can be removed by chemical dehydration from the diluted sulfuric acid. This chemical dehydration process is also energy efficient with 24.76% saving compared with the direct evaporation process. Furthermore, 51.21% of the FeSO4 dissolved originally in the diluted sulfuric acid are precipitated out during the chemical dehydration, which greatly reduces the solid precipitation and effectively alleviates the scaling in the subsequent multi-effect evaporation process.

Montan resin removal and oxidation bleaching are two key procedures for preparing refined montan wax (RMW) from lignite and significantly affect the wax’s color appearance. However, due to the larg...

Lithium–sulfur batteries are considered to be promising energy storage devices owing to their high energy density, relatively low price and abundant resources. However, the low utilization of insulated active materials and shuttle effect have severely hindered the further development of lithium–sulfur batteries. Herein, MoO2 nanoparticles embedded in N-doped hydrangea-like carbon have been synthesized by liquid-phase reaction followed by an annealing process and used as a sulfur host. The nitrogen-doped carbon matrix improves electrical conductivity and provides pathways for smooth electron and Li ion transfer to uniformly dispersed sulfur. Meanwhile, MoO2 nanoparticles can absorb polysulfide ions by forming strong chemical bonds, which can effectively alleviate the polysulfide shuttling effect. These results showed a good rate performance: 1361, 1071, 925, 815 and 782 mA h g−1 at the current densities of 0.1, 0.2, 0.5, 1 and 2 A g−1, and capacity retention of 85% after 300 cycles at 1 A g−1. The excellent performance was due to the synergistic effects of the polar MoO2 and nitrogen-doped carbon matrix, which can effectively restrain and reutilize active materials by absorbing polysulfides and catalyzing the transformation of polysulfides.

The CO2 mineralization is an economical route to reduce CO2 emission for the production of high-value carbonate products. The performance of CO2 indirect mineralization of MgSO 4 by ( NH 4 ) 2 CO 3 solution was studied systematically. The effects of process parameters on the reaction performance and morphology of MgCO 3 · 3 H 2 O were investigated. In the reaction process, three stages were observed, including nucleation induction, solid phase growth and equilibrium stage. The nucleation induction period and equilibrium time are shortened with the increase of reaction temperature, initial reactants concentration, stirring speed and ( NH 4 ) 2 CO 3 / MgSO 4 molar ratio. These parameters also play a vital role in the morphology of products. It was found that the difference between crystal growth rate and mass transfer rate has a significant impact on crystal morphology. A kinetic model was derived from the solid phase growth rate. The estimated activation energies of forward and reverse reaction are 30.37 kJ / mol and 32.71 kJ / mol , respectively.

The peak-loading shift function of sodium-ion batteries in large-grid energy store station poses a giant challenge on the account of poor rate performance of cathodes. NASICON type Na3V2(PO4)3 with a stable three-dimensional framework and fast ion diffusion channels has been regarded as one of the potential candidates and extensively studied. Nevertheless, a multilevel integrated tactic to boost the performance of Na3V2(PO4)3 in terms of crystal structure modulation, coated carbon graphitization regulation, and particle morphology design is rarely reported and deserves much attention. In this study, organic ferric was used to prepare Fe-doped Na3V2(PO4)3@C cathode on the account of low cost, environmental friendliness, and catalytic function of Fe on carbon graphitization. The density functional theory calculation depicts that the most stable site for Fe atom is the V site and moderate replacement of Fe at V position would reduce the band gap energy from 2.19 by 0.43 eV and improve the electron transfer, ...

Ni-rich layered transition metal oxides show great energy density but suffer poor thermal stability and inferior cycling performance, which limit their practical application. In this work, a minor content of Co and B were co-doped into the crystal of a Ni-rich cathode (LiNi0.8Co0.1Mn0.1O2) using cobalt acetate and boric acid as dopants. The results analyzed by XRD, TEM, XPS and SEM reveal that the modified sample shows a reduced energy barrier for Li+ insertion/extraction and alleviated Li+/Ni2+ cation mixing. With the doping of B and Co, corresponding enhanced cycle stability was achieved with a high capacity retention of 86.1% at 1.0C after 300 cycles in the range of 2.7 and 4.3 V at 25 °C, which obviously outperformed the pristine cathode (52.9%). When cycled after 300 cycles at 5C, the material exhibits significantly enhanced cycle stability with a capacity retention of 81.9%. This strategy for the enhancement of the electrochemical performance may provide some guiding significance for the practical application of high nickel content cathodes.

Modifying separator with metal oxides has been considered as a strong strategy to inhibit the shuttling of soluble polysulfide in the lithium-sulfur battery (Li-S battery). Manganesedioxide (MnO

The dissolution of polysulfides in an electrolyte is a thermodynamically favorable process, which in theory means that the shuttle effect in lithium-sulfur batteries (LSBs) cannot be completely suppressed. So, it is very important to modify the separator to prevent the migration of polysulfides to the lithium anode. The traditional coating modification process of the separator is cumbersome and uses a solvent that is harmful to the environment, and too many inactive components affect the overall energy density of the battery. It is thus imperative to find a simple and environmentally friendly modification process of the separator. In this study, a fast chemical film-forming method is proposed to modify the separator of a lithium-sulfur battery using tannic acid (TA) and cobalt ions (Co2+). This method requires only simple steps and environmentally friendly raw materials to obtain a thin coating (only 5.83 nm) that can effectively inhibit the shuttle effect. The lithium-sulfur battery with the TA-Co separator shows superior long cycle performance. After 500 cycles at 0.5 C, the capacity decay rate of each cycle is only 0.065%. On the other hand, the TA-Co separator can inhibit the growth of lithium dendrites and help to build a stable lithium anode, which can exhibit minimal polarization (56 mV) in a lithium-lithium symmetrical battery at the current density of 2 mA cm-2. The rapid and simple modification method proposed in this study has a certain reference value for the future large-scale application of lithium sulfur batteries.

The disposal and resource utilization of waste activated sludge (WAS) is a big challenge for its high moisture content. Ionic liquid (IL), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][OTf]), was innovatively used as a conditioner to improve the dewatering performance of WAS. The WAS was characterized by flocs size, three-dimensional excitation-emission matrix (3D-EEM), zeta potential, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) for the investigation of intensification mechanism. The results showed that the dewatering performance of WAS conditioned by [EMIM][OTf] was significantly improved. The moisture content was successfully decreased to 64.99±0.92 %, and the intensification mechanism was investigated. The results showed that the structures of extracellular polymeric substance (EPS) were destroyed by [EMIM][OTf]. It brought a sharp decrease of the contents of polysaccharides (PS), proteins (PN), humic acid (HA) and fulvic acid (FA) in tightly bound extracellular polymeric substance (TB-EPS) structure. The inactivation of microbial cells promoted the disintegration of flocs. Large flocs were converted into unstable small particles and biopolymers. In addition, the negative charges of WAS were also neutralized for dissolution of biopolymers in [EMIM][OTf], and the electrostatic repulsion between flocs was weakened. [EMIM][OTf] was easily recycled five times. The research results indicate that specific IL, such as [EMIM][OTf], is a potential conditioner to improve the dewatering performance of WAS.

Separator modification with metal oxide and carbon composite recently has become a potential and competitive way to confine polysulfide diffusion and mitigate the shuttling effect. However, other modification methods also have an impact on the stability of the modified layer and the enhancement of electrochemical performance. Herein, we first design a novel bifunctional separator combined with one self-assembled FeOOH layer via a chemical way and one conductive g-C

Lithium-sulfur batteries have attracted much attention as a promising next-generation energy storage system due to their high theoretical specific capacity and energy density. However, lithium-sulfur batteries are still facing some problems that hinder their large-scale commercial application. High conductivity molybdenum dioxide coated with carbon composite (MoO

As a lithium-ion secondary battery with high energy density, lithium-sulfur batteries have very bright development prospects. But the shuttle effect is still a thorny issue in the development process. The N, O co-doped chlorella-based biomass carbon (CBBC) synthesized by chemical activation method possesses a microporous and mesoporous composite structure, large specific surface area, and good electrical conductivity. The CBBC interlayer can improve the wettability between the separator and the electrolyte, and accelerate the transmission of Li+. N, O heteroatoms have a strong chemical adsorption operation for LiPs. The modified separator restrains lithium polysulfide through physical barriers and chemical adsorption, and improves the capacity and cycle performance of lithium-sulfur batteries. The batteries with CBBC exhibit excellent cycling stability (0.067% per cycle at 0.5C) and better rate performance (918 mAh g−1 at 2C). The first discharge capacity at 0.05C was 1540 mAh g−1. Even after 600 cycles the discharge capacity retains 656 mAh g−1 at 0.5C. The low price and simple preparation of CBBC interlayer is an attractive choice for improving lithium-sulfur batteries.

Lithium-sulfur batteries are considered to be promising energy storage devices owing to their high energy density, relatively low price and abundant resources. However, the low utilization of insulated active materials and shuttle effect have severely hindered the further development of lithium-sulfur batteries. Herein, MoO

Injection of phase transition from a layered to rock-salt phase into the bulk lattice and side reactions on the interfacial usually causes structure degradation, quick capacity/voltage decay, and even thermal instability. Here, a self-formed interfacial protective layer coupled with lattice tuning was constructed for Ni-rich cathodes by simultaneous incorporation of Zr and Al in a one-step calcination. The migration energy between Zr and Al from the surface into the bulk lattice induces dual modifications from the surface into the bulk lattice, which effectively decrease the formation of cation mixing, the degree of anisotropic lattice change, and the generation of microcracks. With the stabilization role provided by the doped Zr-Al ions and protective function endowed by the surface layer, the modified cathode material exhibits significantly enhanced capacity and voltage retention. Specifically, the capacity retention for the modified cathode material reaches 99% after 100 cycles at 1 C and 25 °C in a voltage range of 3.0-4.3 V, which outperformed that for the pristine cathode (70%). The declination values of the average voltage for the modified cathode are only 0.025 and 0.097 V after 100 cycles at 1 C in voltage ranges of 3.0-4.3 and 2.8-4.5 V, respectively, which are much lower than those for the pristine cathode (0.230 and 0.405 V). The synchronous accomplishment of modification from the surface into the bulk lattice for Ni-rich materials with multiple elements in a one-step calcination process would provide some referenced value for the preparation of other cathode materials.

Phase transition occurring during cycling plays a fundamentally important role in the cycling performance of nickel-rich cathodes. Here, splitting of two O3 phases, rather than the often observed O1 phases in the conventional LiCoO$_{2}$ electrode, was discovered in LiNi$_{0.85}$Co$_{0.10}$Mn$_{0.05}$O$_{2}$ at a high-voltage region (>4.6 V). Such degradation could be mitigated via Al doping.

Lithium sulfur batteries are one of the most potential rechargeable energy storage devices due to its high energy density and low cost. Nevertheless, the practical applications are heavily hindered by polysulfide shuttle effect, which would cause fast capacity fading. Polysulfide adsorption has been proved to be an effective strategy via chemical bonding or physical constraint. Here, a fresh LixLayTiO3 and acetylene black hybrid coated separator was constructed to suppress the migration of polysulfides and served as an upper current collector to fully utilize the active material. The acetylene black embellished separator and the pristine one were used as reference. Comprehensive and systematic results proved that the hybrid coated separator could not only effectively trap polysulfides, but also promote the conversion of polysulfides, which would improve the rate and cycle performance. The as-prepared sample with 1.0% LixLayTiO3 addition showed the best electrochemical performance with a high capacity of 890 mA h g-1 at 1600 mA g−1. An enhanced cycling performance with 716 mA h g-1 retained after 100 cycles at 800 mA g−1 was observed, corresponding to a capacity retention of 81.2%. In summary, this study provides a simple, low cost and effective approach to promote the development of lithium sulfur batteries.

The lithium sulfur (Li-S) batteries are greatly fascinating as the next-generation storage devices owing to their high theoretical energy density and low cost. However, the fast capacity decay resulting from the “shuttle effect” of polysulfide ions and the irregular deposition of the discharge products (Li2S/Li2S2) severely hinder their commercial application. Herein, micro-mesoporous carbon–MnO (MnO/MPC) composites were synthesized with wet impregnation method and applied as the cathode material. In Li-S cells, the MnO/MPC@S cathode showed a rather better cycling stability over 150 cycles than a MPC@S cathode (sulfur loading ∼74%). The influences of the MnO amount and the heat treatment temperature were investigated and optimized. The 10%-MnO/MPC@S cathode material calcined at 600 °C showed excellent rate capability and cycling stability. Owing to the polar MnO nanoparticles, the soluble lithium polysulfides (Li2Sn, 2

Fe3+ is an impurity of the raw phosphoric acid from wet-process route and the waste phosphoric acid from the etching process of electronic industry. The effects of temperature, the Cl− content and TBP dosage on the extraction performance of synthesized extractants to Fe3+ in raw phosphoric acid from HCl wet-process route were investigated systematically. The results show that the extractant containing 12.5 vol% TBP and 87.5 vol% kerosene effectively extracted Fe3+ at 293.15 K from raw phosphoric acid containing 15.8 wt% Cl−. The extraction efficiency of 100% was realized by counter-current three-stage extraction. The extract phase was characterized by FT-IR and UV–vis. The results show that Fe3+ was extracted by TBP with the form of HFeCl4. The interaction between TBP and HFeCl4 was simulated by DFT (density functional theory). The lowest energy structure, electrostatic potential distribution, energy change, bond level analysis, electron transfer, frontline molecular orbital and other information of the possible complex were simulated systematically. The results of the characterization of the extraction phase and DFT simulation were used to clarify the extraction mechanism and the structure of the complex. The simulation results show that the lone-pair electrons of the P O double bond in TBP has a strong complexation interaction with the empty orbital of HFeCl4 and a strong bond Fe O{TBP} is formed in the extraction process. The bond length of formed Fe O{TBP} is 2.05A, the LBO bond level of Fe O{TBP} is 0.076 (0.075), the Mayer bond level of Fe O{TBP} is about 0.16, the ρb values of Fe O{TBP} bond critical points range from 0.252 to 0.271 e−/bohr3. A minimum electrostatic potential of −50.59 kcal/mol is existed in TBP at the vicinity of O atom in P O double bond. Two maximum electrostatic potential of 69.43 kcal/mol and 69.92 kcal/mol are distributed symmetrically on the opposite sides of the Fe vicinity of HFeCl4. Each HFeCl4 molecule combines two TBP molecules on the opposite sides, and the binding sites are near the O atom of the P O double bond of TBP and near the Fe atom of HFeCl4. The absolute value of the binding energy is greater than 165 kJ/mol. The complexation reaction of TBP and HFeCl4 occurs through the surface electrostatic potential attraction and molecular orbital complementation forms. The results are helpful to understand the extraction mechanism of TBP to extract Fe3+ from phosphoric acid.

Lithium-sulfur (Li-S) batteries are recognized as one of the most promising energy storage technologies. However, the “shuttle effect” of polysulfides and poor reaction kinetics severely impede the commercial application. In this study, a three-dimensional (3D) multi-functional C@SnS2 compound material is designed for PP separator modification. Chemical etching is skillfully used to construct evenly distributed vacancies and activated carbon sites from ZIF-67 in one step, which is beneficial to the uniform growth of SnS2 subsequently. The C@SnS2 shows a synergic effect between porous carbon matrix and polar SnS2 due to the unique structure, combining electrochemical kinetics and anchoring-catalytic-conversion of polysulfides. Therefore, excellent long-term cycling performance (646 mAh g−1 after 500 cycles at 1 C, the loss rate of 0.062% per cycle) and outstanding rate capacity (793 mAh g−1 at 2 C) are obtained. This work provides an effective attempt to inhibit the shuttle effect and improve the kinetic process in Li-S batteries.

A novel strategy of room-temperature synthesis of MIL-100(Fe) with organic amine as deprotonating agent was proposed. The as-prepared solid product was denoted as R-MIL-100(Fe). The material was systematically characterized via XRD, FT-IR, XPS and SEM. The effects of operation parameters such as initial fluoride concentration, reaction time, initial pH and co-existing anions on the fluoride adsorption performance of the synthesized R-MIL-100(Fe) were studied. The maximum fluoride adsorption capacity of R-MIL-100(Fe) was as high as 23.53 mg/g at 298 K in the fluoride solution. The results indicate that the adsorption process of fluorine on R-MIL-100(Fe) belongs to surface adsorption and intraparticle diffusion. An excellent fluoride adsorption performance of R-MIL-100(Fe) was observed in a wide pH range of 4–10. The co-existing anions including Cl-, NO3- and SO42- almost had no negative effects on the adsorption performance of R-MIL-100(Fe). However, the present of CO32- or HCO3- brought an obvious reduction of F- adsorption capacity of R-MIL-100(Fe). Thermodynamic study results illustrate that the adsorption process was an exothermic chemisorption. Chemical combination of iron and fluorine was confirmed by FT-IR and XPS. The strong combination brings the excellent F- adsorption performance of MIL-100(Fe). R-MIL-100(Fe) was successfully regenerated and recycled five cycles with an excellent regeneration ability and recyclability.

Arsenic pollution with high toxicity is widely distributed and needs to be addressed urgently. Sulfhydryl-functionalized chitosan (Chi-SH) was prepared by the reaction of 3-mercaptopropyltrimethoxysilane with chitosan in ethanol-water solution and used to remove As(III) from water. The prepared absorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results confirmed the successful grafting of sulfhydryl groups with chitosan. The adsorption performance of Chi-SH was studied systematically. The Chi-SH showed excellent As(III) removal efficiency of over 99% from 10 mg/L As(III) solution in the pH range of 3.0–10.0. The adsorption behavior of As(III) on Chi-SH accorded with the pseudo-second-kinetic (R2 ≥ 0.972) model and Langmuir adsorption isotherm (R2 ≥ 0.959). The maximum adsorption capacity of Chi-SH was 21.01 mg/g at 298 K and pH 7. The background electrolyte (NaNO3) concentration and the presence of co-existing ions almost do not affect the adsorption process. The Chi-SH was successfully regenerated by 0.5 mol/L oxalic acid for 1.5 h. The removal efficiency of As(III) is over 80% in two cycles.

Shuttle effect is the core problem in lithium-sulfur battery, which makes internally poor dynamics and bad cycle stability of the lithium-sulfur battery (Li–S battery). In this study, a sheet nitrogen-doped vanadium dioxide material that roots in a metal-organic framework (SVO) was designed and synthesized. SVO has a unique two-dimensional structure and uniform distribution of metal sites. It leads to the adsorption-catalytic synergistic effect that can efficiently anchor polysulfides and promote sulfur conversion kinetics to significantly alleviate the shuttle effect. With the metal-organic framework precursor synthesized under mild conditions of room temperature and pressure, the SVO materials used to modify the separator can be simply obtained by calcination. Especially, the modified material exhibits excellent electrochemical performance with only 0.081% degradation of capacity per cycle at 1C after 500 cycles. Even under a harsh condition (sulfur loading = 6.3 mg cm−2, E/S = 5), the battery with SVO/AB separator is available to reach an area capacity of about 4.16 mAh cm−2 at 0.1C. Meantime, as for the anode side, SVO/AB separator can be used as lithium-ion guides to keep stable lithium-ion stripping/plating and inhibit the growth of lithium dendrite. The battery with SVO/AB separator also shows superior performance under high and low temperatures.

MnO@C/N composite with expanded cauliflower-like morphology was prepared via one-pot L-tryptophan assisted hydrothermal method following by annealing in Ar atmosphere. The cauliflower structure was assembled by porous nanowires that composed of MnO nanoparticles wrapped by continuous N-doped amorphous carbon matrix. Superior electrochemical performances were obtained in both lithium/sodium ion batteries. And the reaction kinetics of MnO@C/N in lithium/sodium ion batteries were analyzed and compared. More than 837 mAh g−1 could be retained after 300 cycles at 500 mA g−1. And a high reversible capacity of 336 mAh g−1 at 5000 mA g−1 also demonstrate the excellent rate performance of MnO@C/N for LIBs. As to SIBs, 123 mAh g−1 could be maintained after 200 cycles at 100 mA g−1. The superior performances could be attributed to the peculiar porous micro-nano structure and N-doped amorphous carbon coating. The reaction kinetics results revealed that the capacitive-controlled capacity would dominate of the electrochemical performance in SIBs and the diffusion-controlled capacity could play a more important role in LIBs, due to the atom weight and size of Na+ is larger than Li+.

Even though significant improvement has been made in the Li–S battery technology, the poor cycling and rate performance have always limited the further growth. Thus, the development of cost-effective and high performing electrodes is considered to be an important technology for the practical aspect. It is quite logical that the porous electrode systems can improve the electrochemical performance of a given battery system. Here, this study benchmarks a new class of electrodes based on double (micro and meso)porous carbon spheres (MMPCs) prepared by a facile soft template method followed by wet chemical etching. The particle size analysis, performed by scanning electron microscopy, shows that the templating agents, such as sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide(CTAB), have a distinct effect on the size distribution of carbon particles. Different electrochemical characterizations have been carried out to understand the effect of SDS and CTAB on the electrochemical performance of carbon-sulfur nanocomposite electrode. BET analysis shows that the pore size distribution of the carbon spheres prepared by only the soft template method (MPCs) is mainly in the micropore range, which limits the storage and the dispersive capacity. However, the etched samples (MMPCs) showed better electrochemical performance, such as high initial discharge capacity of 921 mAh g−1(sulfur loading ∼77.2%) with 82.7% capacity retention at the end of 150 cycles at 200 mA g−1 and an impressive rate capability of 1086 mAh g−1 at a current density of 100 mA g−1.This improved performance could be attributed to the double porous structure of MMPCs. Such a feasible and facile architecture provides a good strategy to prepare other different materials that require better material dispersion and electrode/electrolyte interactions.