Boosting Aqueous Zn/MnO2 Batteries via a Synergy of Edge/Defect-Rich Cathode and Dendrite-Free Anode.

Aqueous Zn/MnO2 batteries exhibit huge potential for grid-scale energy storage but suffer from poor cycling stability derived from both structural instability of cathode and Zn dendrite growth of anode. Here, we report a high-performance aqueous Zn/MnO2 battery with ZnSO4-based electrolyte, comprising a nanoparticle-like cathode with abundant surface oxygen defects (MO-Vo) and a dendrite-free Zn anode. The transformation from nanowire (α-MnO2) to nanoparticle (MO-Vo) was found by tuning the annealing conditions in an argon flow. Moreover, the small size of MO-Vo nanoparticles can effectively promote the spatially uniform distribution of volume stress during carrier intercalation, boosting the structural stability of the MO-Vo cathode. Moreover, it was found that the intercalation pseudocapacitive behavior of Zn2+ in the MO-Vo cathode can be strongly boosted by tailoring the surface oxygen defect of MnO2 based on the calculations and experiments, thereby achieving enhanced cycling stability and redox kinetics. Additionally, the addition of K2SO4 additive into the electrolyte can tailor the deposition behavior of Zn2+, enabling stable Zn stripping/plating without dendrites. Therefore, the assembled Zn/MO-Vo batteries exhibit a high energy density and excellent long-term cyclability over 1400 cycles. Besides, the reaction mechanism of pseudocapacitive Zn2+ intercalation and H+ intercalation for the MO-Vo cathode was revealed via ex situ characterizations.

Confining Pyrrhotite Fe7 S8 in Carbon Nanotubes Covalently Bonded onto 3D Few-Layer Graphene Boosts Potassium-Ion Storage and Full-Cell Applications.

The pyrrhotite Fe7 S8 with mixed Fe-valence possesses high theoretical capacity, high conductivity, low discharge/charge voltage plateaus, and superior redox reversibility but suffers from structural degradation upon (de)potassiation process due to severe volume variations. Herein, to conquer this issue, a novel hierarchical architecture of confining nano-Fe7 S8 in carbon nanotubes covalently bonded onto 3D few-layer graphene (Fe7 S8 @CNT@3DFG) is designed for potassium storage. Notably, CNTs could successfully grow on the surface of 3DFG via a tip-growth model under the catalytic effect of Fe3 C. Such structure enables the hierarchical confinement of 0D nano-Fe7 S8 to 1D CNTs and further 1D CNTs to 3DFG, effectively buffering the volume variations, prohibiting the agglomeration of Fe7 S8 nanograins, and boosting the ionic/electronic transportation through the stable and conductive CNTs-grafted 3DFG framework. The as-prepared Fe7 S8 @CNT@3DFG electrode delivers an exceptional rate capability (502 mAh g-1 at 50 mA g-1 with 277 mAh g-1 at 1000 mA g-1 ) and an excellent long-term cyclic stability up to 1300 cycles. Besides, the in-situ XRD and ex-situ XPS/HRTEM results first elucidate the highly reversible potassium-storage mechanism of Fe7 S8 . Furthermore, the designed potassium full-cell employing Fe7 S8 @CNT@3DFG anode and potassium Prussian blue (KPB) cathode delivers a promising energy density of ≈120 Wh kg-1 , demonstrating great application prospects.

S-containing and Si-containing compounds as highly effective electrolyte additives for SiOx -based anodes/NCM 811 cathodes in lithium ion cells.

Recently, high-energy density cells containing nickel-rich cathodes and silicon-based anodes have become a practical solution for increasing the driving range of electric vehicles. However, their long-term durability and storage performance is comparatively poor because of the unstable cathode-electrolyte-interphase (CEI) of the high-reactivity cathode and the continuous solid-electrolyte-interphase (SEI) growth. In this work, we study several electrolyte systems consisting of various additives, such as S-containing (1,3,2-dioxathiolane 2,2-dioxide (DTD), DTD + prop-1-ene-1,3-sultone (PES), methylene methanedisulfonate (MMDS)) and Si-containing (tris(trimethylsilyl) phosphate (TTSP) and tris(trimethylsilyl) borate (TMSB)) compounds, in comparison to the baseline electrolyte (BL = 1.0 M LiPF6 + 3:5:2 w-w:w EC: EMC: DEC + 0.5 wt% lithium difluoro(oxalato)borate (LiDFOB) + 2 wt% lithium bis(fluorosulfonyl)imide (LiFSI) + 2 wt% fluoroethylene carbonate (FEC) + 1 wt% 1,3-propane sultone (PS)). Generally, electrolytes with Si-containing additives, particularly BL + 0.5% TTSP, show a lower impedance increase in the full cell, better beginning-of-life (BOL) performance, less reversible capacity loss through long-term cycles and better storage at elevated temperatures than do electrolytes with S-containing additives. On the contrary, electrolytes with S-containing additives exhibit the advantage of low SEI impedance but yield a worse performance in the full cell than do those with Si-containing additives. The difference between two types of additives is attributed to the distinct function of the electrodes, which is characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS), which was performed on full cells and half cells with fresh and harvested electrodes.

Novel ionic surface imprinting technology: design and application for selectively recognizing heavy metal ions.

Traditional bulk polymerization imprinted technology and existing surface imprinted technology have some congenital defects. Therefore, it is necessary to design more efficient surface imprinted technology. In this paper, novel surface imprinting technology with higher imprinting efficiency is well designed. It fully realizes the synchronization of polymer crosslinking and template imprinting. Then the surface imprinted polymers (SIPs) are synthesized using metal ions as a template. The physicochemical characteristics of the SIPs are characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) studies, Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The adsorption performances and recognition selectivity of the SIPs towards the template are investigated by a batch method. The experimental results show that the SIPs possess excellent adsorption ability and selectivity towards the template. The selectivity coefficients of the SIPs prepared in this study are higher than those of IIPs prepared by other imprinting methods. The adsorption process could be well described by the Lagergren-first-order model and Langmuir monolayer chemical adsorption. The SIPs have good chemical stability and reusability. Consecutive adsorption-desorption experiments show that the exhausted SIPs could be effectively regenerated, and the regenerated SIPs could be reused without a significant reduction in adsorption capacity or selectivity coefficient.

Multi-stage constant-current charging protocol for a high-energy-density pouch cell based on a 622NCM/graphite system.

A novel multi-stage-constant-current (MS-CC) charging protocol, which charges high-energy-density lithium-ion cells (LICs) at a faster rate, is presented herein. In this work, the 0-80% state of charge (SoC), according to the maximum charging rate, yields acceptable results for different SoCs, and the charging process is divided into three parts. Twelve groups of experiments are designed under the desired conditions of avoiding lithium plating and using a charging time of less than 36 min, and 1.5C constant current charging is used as a comparison experiment. The full pouch cells are dismantled, and the lithium deposition after 1.5C charging is more extensive than that after the MS-CC charging protocol. In addition, the capacity retention for 1.5C charging is 95.7%, while those for the 12 MS-CC charging protocol groups are within the range of 99.5-100.0% after the 300th cycle at 25 °C. When the temperature is 25 °C and 50 °C, the capacity retention of the 12 MS-CC charging protocol groups remains similar, but when the temperature drops to 10 °C, the capacity retention decreases except for the 2.0-1.5-0.9C and 1.8-1.5-0.9C groups. At the 510th cycle, the capacity retention of the 2.0-1.5-0.9C and 1.8-1.5-0.9C groups is 99.6% and 99.9%, respectively; the values of the other 10 groups are between 95.0% and 98.2%. The excellent electrochemical performances of the MS-CC charging protocol may be due to the minimal damage of cell materials caused by the step-type high-rate charging process; thus, the degree of polarization is small. Furthermore, compared with the conventional constant constant-current (CC) charging procedure, MS-CC charging greatly shortens the charging time.

Self-discharge rates in cells have a critical effect on the cycle life of parallel lithium-ion batteries.

More than two parameters are adopted to sort the lithium ion cells (LICs) for better performance in the production process, such as capacity, open-circuit voltage (OCV), direct current resistance (DCR), et al. However, more sorting parameters make mass production more complex. In order to solve this conflict, we compare capacity, OCV, DCR, and self-discharge rate (k OCV) in this paper, investigate their different effects on the cycle life of parallel LICs through analyzing the relationship between component cell variations and the durability of the parallel blocks. We find that the variations of the self-discharge rate in cells significantly affect the discharge capacity retention of the blocks: bigger variation in the cells results in a better cycle life of parallel LICs. Thus, it is prudent to perform cell sorting for the assembly of superior blocks based on the self-discharge rates of the cells.

Rate dependence of cell-to-cell variations of lithium-ion cells.

Lithium-ion cells are commonly used in a multicell configuration in power devices and electric vehicles, making the cell-to-cell variation (CtCV) a key factor to consider in system design and management. Previous studies on CtCV have two major limitations: the number of cells is usually less than one hundred, and the cells are usually commercial cells already subjected to cell-screenings. In this article, we first make a statistical analysis on the CtCV of 5473 fresh cells from an automotive battery manufacturer before the cell-screening process. Secondly, 198 cells are randomly selected from these 5473 cells and the rate dependence of the CtCV is examined, focusing on the correlations of capacity versus weight and capacity versus resistance, corresponding to thermodynamic and kinetic factors, respectively. The rate dependence of these two correlations is explained from a phenomenological model. Finally, eight cells from the 198 cells are further characterized with electrochemical impedance spectroscopy method to elucidate the kinetic origins of the CtCV.

Adsorption and recognition characteristics of surface molecularly imprinted polymethacrylic acid/silica toward genistein.

In this paper, on the basis of surface-initiated graft polymerization, a new surface molecular imprinting technique is established by molecular design. And molecularly imprinted polymer MIP-PMAA/SiO2 is successfully prepared with genistein as template. The adsorption and recognition characteristics of MIP-PMAA/SiO2 for genistein are studied in depth by using static method, dynamic method and competitive adsorption experiment. The experimental results show that MIP-PMAA/SiO2 possesses very strong adsorption affinity and specific recognition for genistein. The saturated adsorption capacity could reach to 0.36mmolg(-1). The selectivity coefficients relative to quercetin and rutin are 5.4 and 11.8, respectively. Besides, MIP-PMAA/SiO2 is regenerated easily and exhibits excellent reusability.

Adsorption of phenolic compounds from aqueous solution using salicylic acid type adsorbent.

In this study, 5-aminosalicylic acid (5-ASA) was successfully grafted onto the poly(glycidyl methacrylate) (PGMA) macromolecular chains of PGMA/SiO(2) to obtain adsorbent ASA-PGMA/SiO(2). The adsorption properties of ASA-PGMA/SiO(2) for phenolic compounds were studied through batch and column methods. The experimental results showed that ASA-PGMA/SiO(2) possesses strong adsorption ability for phenolic compounds, and its adsorption capacity for phenol, 4-chlorophenol, and p-nitrophenol reaches 1.0, 1.1, and 1.32 mmolg(-1), respectively. In addition, pH has a great influence on the adsorption capacity. The adsorption isotherm data obeyed the Langmuir model well than Freundlich model. The desorption of phenolic compounds from the ASA-PGMA/SiO(2) adsorbent was most effectively achieved in a 0.1 molL(-1) sodium hydroxide solution. Consecutive adsorption-desorption experiments showed that the ASA-PGMA/SiO(2) adsorbent could be reused almost without any loss in the adsorption capacity.

Efficient removal of heavy metal ions from aqueous solution using salicylic acid type chelate adsorbent.

In this study, 5-aminosalicylic acid was successfully grafted onto the poly(glycidyl methacrylate) (PGMA) macromolecular chains of PGMA/SiO(2) to obtain a novel adsorbent designated as ASA-PGMA/SiO(2). The adsorption properties of ASA-PGMA/SiO(2) for heavy metal ions were studied through batch and column methods. The experimental results showed that ASA-PGMA/SiO(2) possesses strong chelating adsorption ability for heavy metal ions, and its adsorption capacity for Cu(2+), Cd(2+), Zn(2+), and Pb(2+) reaches 0.42, 0.40, 0.35, and 0.31 mmol g(-1), respectively. In addition, pH has a great influence on the adsorption capacity in the studied pH range. The adsorption isotherm data greatly obey the Langmuir and Freundlich model. The desorption of metal ions from ASA-PGMA/SiO(2) is effective using 0.1 mol l(-1) of hydrochloric acid solution as eluent. Consecutive adsorption-desorption experiments showed that ASA-PGMA/SiO(2) could be reused almost without any loss in the adsorption capacity.

Adsorption property and mechanism of composite adsorbent PMAA/SiO2 for aniline.

In this paper, functional monomer methacrylic acid (MAA) was grafted onto the surface of silica gel particles using 3-methacryloxypropyl trimethoxysilane (MPS) as intermedia, and grafting particles PMAA/SiO(2) were prepared. The adsorption properties and mechanism of PMAA/SiO(2) towards aniline were researched through batch and column adsorption methods. The experimental results showed that PMAA/SiO(2) possesses strong adsorption ability for aniline with interaction of hydrogen bond. The saturated adsorption amount could reach up to 140 mg g(-1). The empirical Langmuir isotherm was found to agree well with the equilibrium adsorption data. pH and temperature were found to have great influence on the adsorption amount. Finally, PMAA/SiO(2) was observed to possess excellent reusability properties as well.

Adsorption mechanism and property of a novel adsorption material PAM/SiO2 towards 2,4,6-trinitrotoluene.

2,4,6-Trinitrotoluene (TNT) is toxic and mutagenic to many living organisms, so more and more rigorous limits on the letting amount of TNT have been established. In this paper, functional monomer acrylamide (AM) was grafted step by step on the surface of silica gel particles, and the grafted particle PAM/SiO(2) with strong adsorption ability for TNT was formed. The adsorption mechanism and properties of PAM/SiO(2) for TNT were researched through static and dynamic methods. The experimental results showed that PAM/SiO(2) possesses strong adsorption ability for TNT with interaction of three kinds of hydrogen bonds including peculiar NHcdots, three dots, centeredpi hydrogen bond (aromatic hydrogen bond) and CHcdots, three dots, centeredOC pi hydrogen bond. The saturated adsorption amount could reach to 0.873 mg g(-1). The empirical Freundlich isotherm was found to describe well the equilibrium adsorption data. In addition, the pH and temperature were found to have great influence on the adsorption amount. Mixture solution of HCl and ethanol is used as eluent, and the adsorbed TNT is eluted easily from PAM/SiO(2). Finally, PAM/SiO(2) was found to have excellent reusability.

Adsorption of 2,4,6-trinitrotoluene on a novel adsorption material PEI/SiO2.

In this paper, functional macromolecule polyethyleneimine (PEI) was grafted onto the surface of silica gel particles in order to produce the novel adsorption material, PEI/SiO2. Then this novel material's adsorption properties for TNT were investigated through static methods, and the experimental results showed that PEI/SiO2 possessed strong adsorption ability for TNT. In fact, the saturated adsorption amount could reach 14.47 mg g(-1). The empirical Freundlich isotherm was also found to describe well the equilibrium adsorption data. In addition, the pH and temperature were found to have great influence on the adsorption amount. Finally, PEI/SiO2 was observed to possess excellent reusability properties as well.

Adsorption and recognizing ability of molecular imprinted polymer MIP-PEI/SiO(2) towards phenol.

Firstly, functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles via the coupling grafting method, the adsorption material PEI/SiO(2) was formed. Secondly, the molecular imprinting was carried out towards the macromolecule PEI grafted on the surface of silica particles using phenol as a template and diepoxyalkyl (669) as a crosslinking agent. Finally, imprinted polymer MIP-PEI/SiO(2) with high affinity, specific recognition ability and excellent selectivity for phenol was prepared. The adsorption and recognition ability of MIP-PEI/SiO(2) for phenol were researched by static methods. The experimental results show that MIP-PEI/SiO(2) possesses very strong adsorption and recognition ability for phenol. The saturated adsorption capacity could reach to 46.6 mg g(-1). The selectivity coefficients relative to resorcin and p-nitrophenol are 35.41 and 37.40, respectively. The empirical Freundlich isotherm was found to describe well the equilibrium adsorption data. pH and temperature have great influence on the adsorption capacity. Diluted hydrochloric acid solution is used as eluent, and the adsorbed phenol is eluted easily from MIP-PEI/SiO(2).

Adsorption of phenol on a novel adsorption material PEI/SiO2.

In this paper, functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles via the coupling effect of gamma-chloropropyl trimethoxysilane (CP), and the novel adsorption material PEI/SiO2 with strong adsorption ability for phenol was prepared. The adsorption properties of PEI/SiO2 for phenol were researched by both static and dynamic methods. The experimental results show that PEI/SiO2 possesses very strong adsorption ability for phenol, and the saturated adsorption amount could reach to 160 mg g(-1). The empirical Freundlich isotherm was found to describe well the equilibrium adsorption data. pH and grafting amount of PEI have great influence on the adsorption amount. Diluted sodium hydroxide solution is used as eluent, and the adsorbed phenol is eluted easily from PEI/SiO2.

Chelating adsorption properties of PEI/SiO(2) for plumbum ion.

In this paper, a novel adsorption material PEI/SiO(2) with strong adsorption ability towards heavy-metal ions was prepared. In preparation of PEI/SiO(2), functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles via the coupling effect of gamma-chloropropyl trimethoxysilane (CP). The adsorption properties of PEI/SiO(2) for Pb(2+) ion were studied by both static and dynamic methods. The experimental results show that PEI/SiO(2) possesses very strong adsorption ability for Pb(2+) ion, the saturated adsorption amount could reach to 17.5mgg(-1), and the empirical Langmuir isotherm was found to describe well the equilibrium adsorption data. The pH and grafting amount of PEI have great influence on the adsorption amount. The Pb(2+) ions adsorbed on PEI/SiO(2) are eluted easily by diluted hydrochloric acid solution.