RESUMEN

Broadening the charging and discharging voltage window of high nickel cathode material NCM811 is the most expected method to improve the high specific energy density of batteries currently, yet the cathode-electrolyte interface (CEI) formed by the oxidized and decomposed products of carbonate-based electrolyte under high voltage are always so unsatisfied. Therefore, a voltage-stabilizer, TPFPB (Tris(pentafluoro)phenylborane), added into baseline electrolyte (1 M LiPF6 in EC:EMC:DMC=1:1:1 vol%) to promote the electrochemical performance of the battery at 4.5 V. The results interpret that the TPFPB-contained NCM811-Li half-cells exhibit high specific capacity (167.10 mAh/g), excellent capacity retention rate (CRR) (75.37 %), and high rate performance (173.3 mAh/g at 5C) during 4.5 V. Meanwhile, through the analysis of the physical characterization techniques. the B- and F-rich interfacial layer, named as CEI film, existing at the interface between the cathode and the electrolyte, produced under 4.5 V, is superior, resulting in impeding the structural collapse of the cathode material and the continued dissolution of transition metal ions (TMn+) from the cathode material, as well as, ameliorate the electrochemical polarization of the battery, ultimately, it can stabilize the electrochemical performance of the battery under high voltage. Therein, the present work elucidate a new and substantial approach to enhance the high-voltage performances of rich-Ni cathode materials.

RESUMEN

Ni-Co-Mn complexed 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA-NiCoMn) is prepared by hydrolysis of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and complexed reaction with Ni, Co and Mn ions. At the same time, graphene was added to PTCDA-NiCoMnin situ to obtain graphene in situ composited Ni-Co-Mn complexed 3,4,9,10-perylenetetracarboxylic dianhydride composites (PTCDA-NiCoMn-G). The prepared PTCDA-NiCoMn composite exhibited a fibrous structure, and the number of pore units increased with the expansion of the fibrous structure. After the in situ recombination of graphene, shorter PTCDA-NiCoMn tubular fibers were dispersed between the thin layers of graphene, showing a larger surface area with more PTCDA-NiCoMn active components exposed, which is conducive to better electrochemical properties. As a result, the initial charge/discharge capacities of PTCDA-NiCoMn and PTCDA-NiCoMn-G electrodes are 1972.9 and 1806.6 mA h g-1 with initial coulombic efficiencies of 56.3% and 62.52%, respectively, at 100 mA g-1. After 200 cycles, the charge/discharge capacities of PTCDA-NiCoMn and PTCDA-NiCoMn-G are 617.0 and 876.4 mA h g-1 with capacity retention ratios of 51.4% and 73.0% at 100 mA g-1, respectively. Similarly, PTCA-NiCoMn-G electrodes show higher capacities than the PTCA-NiCoMn electrode at different current densities of 0.1, 0.2, 0.5, 1.0, 2.0 and 5 A g-1. The results show that PTCDA-NiCoMn-G electrode displays superior capacity, ICE, cycle and rate behaviors. The complexation of NiCoMn reduces the solubility of the PTCDA active units in the electrolyte, and the in situ recombination of graphene increases the dispersion of the active components, exposes more active sites, and effectively improves the conductive performance, which contributes to the electrochemical properties of the PTCDA-NiCoMn-G electrode.

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Phosphorus removal has been explored for a long time, however sustainable phosphorus adsorption and recovery with adsorbents recycling is rarely reported. This work proposes a sustainable phosphorus recycling route with calcium-modified powdered activated carbon with chitosan (Ca-PAC-CTS). The morphology, functional groups and crystal structure of Ca-PAC-CTS were characterized. The maximum phosphorus adsorption capacity was 16.73 mg/g Ca-PAC-CTS with Langmuir model at 298 K. Stable phosphorus sorption on Ca-PAC-CTS could be observed at the large range of pH (4- 10) when coexisting with NO3-, SO42-, Cl- and F-, except HCO3-. 98.95 % The recovery of adsorbed phosphorus could get to 98.95 % using 0.05 M sulfuric acid solution, and the phosphate adsorption efficiency through Ca-PAC-CTS remained to be more than 80 % after five adsorption-desorption cycles, suggesting that Ca-PAC-CTS was one of the promising adsorbents for sustainable removal and recovery of phosphorus in aqueous solution.

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A novel Mg-loaded chitosan carbonized microsphere (MCCM) was prepared for simultaneous adsorption of ammonium and phosphate in this study, through the investigation of preparation procedures, addition ratio, and preparation temperature. Pollutants removals by MCCM were more acceptable with 64.71% for ammonium and 99.26% for phosphorus, compared with chitosan carbonized microspheres (CCM), Mg-loaded chitosan hydrogel beads (MCH) and MgCl2·6H2O. Addition ratio of 0.6:1 (mchitosan: mMgCl2) and preparation temperature of 400 °C in MCCM preparation were responsible for pollutant removal and yield. The effect analysis of MCCM dosage, solution pH, pollutant concentration, adsorption mode and coexisting ions on the removal for both ammonium and phosphate indicated that pollutants removals were increased with increasing MCCM dosages, and achieved the peak at pH 8.5, but presented to be stable with Na+, K+, Ca2+, Cl-, NO3-, CO32- and SO42-, except for Fe3+.Adsorption mechanisms discussion implied that simultaneous ammonium and phosphate removal with MCCM was attributed to struvite precipitation, ion exchange, hydrogen bonding, electrostatic attraction and Mg-P complexation, suggesting that MCCM presents a new way for simultaneous concentrated ammonium and phosphate removal in wastewater treatment.

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RESUMEN

The periscope phone lens has a bright application prospect; however, the problem of a large chipping size in the grinding process for the periscope phone lens module components seriously limits its development. We address the problem of the large edge chipping size in the grinding process of small-sized module components of periscope mobile phone cameras by investigating the influence of the grinding speed, feed speed, and grinding depth on the chipping size through theoretical simulation analysis and single-factor variable experimental verification. The optimal grinding process parameters were preferred, and yield experiments were conducted using the preferred process parameters. The results show that increasing the grinding speed and decreasing the feed speed and grinding depth can effectively suppress the chipping size of the component grinding edge.

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In this work, a novel high-voltage electrolyte additive, tetraethylthiophene-2,5-diylbismethylphosphonate (TTD), was synthesized, and the influence of TTD on the electrolyte and its electrochemical performance under different voltages were studied by changing the content of the TTD additive. The results showed that the TTD additive significantly improved the capacity, cycle stability, and rate capability of batteries when charging/discharging at high voltages. After adding 1 % TTD to the basic electrolyte, the capacity retention rate of batteries after 200 cycles at 4.2, 4.3, 4.4, and 4.5 V increased by 20.8, 18.3, 50, and 31.9 %, respectively. In addition, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) results showed that TTD could effectively inhibit the decomposition of the electrolyte and participate in the formation of a uniform, thin, and stable cathode electrolyte interphase (CEI) film on the electrode surface, thereby effectively inhibiting the side reaction between the electrolyte decomposition product and the CEI membrane, and finally improving the high-voltage performance of the battery. The TTD additive may provide a cost-effective solution for high-performance high-voltage electrolytes.

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Sludge-based biochars (SBB) were prepared to evaluate their physiochemical properties and safety performance for the possible application in soil amendments in this study. SBB were produced at the temperatures ranging from 300 to 900 °C at 200 °C intervals. Both the solid fraction and the soluble organic fraction of SBB were analyzed. The pyrolysis temperature was found to affect the characteristics of solid fraction of the SBB greatly, in terms of the pH, surface area and functional groups. The content and composition of dissolved organic matter in SBB were influenced evidently by pyrolysis temperatures, which was mainly comprised of humic-like compounds with the molecular weight in a range of 0.13-2.4 × 105 kDa. The safety performance of heavy metals in SBB at different temperatures were analyzed: (i) The bioavailable fractions (F1+F2+F3) of heavy metals significantly decreased from 91.65% to 9.44% for Cu, from 98.82% to 63.34% for Zn, from 97.91% to 52.11% for As, from 55.91% to 4.87% for Pb, from 78.20% to 12.50% for Cd, and from 73.51% to 9.57% for Cr when sludge was pyrolyzed to biochars at 900 °C.; (ii) Acid and alkaline conditions promoted the leaching of heavy metals from SBB. The luminescence inhibition of Vibrio fischeri was significantly decreased from 81.41% to 6.01% with the increasing pyrolysis temperatures. Compared with the raw sludge addition, the shoot length, root length and activities of soil microbes in sandy soil and loamy soil with pyrolyzed sludge under different pyrolysis temperatures were increased by 37.5-53.32%, 66.81-96.45%, 92.31-157.69% and 154.74-195.76%, respectively. The biotoxicity tests indicated the relatively safe and reliable performance of SBB. The study provided significant perspectives on the application of SBB as the potential soil amendments.

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Dynamic membranes (DMs) have been of great interest in recent years because they can reduce energy consumption and costs during wastewater treatment. Dynamic membranes are a promising technology for the removal of low-density, non-degradable micro-particles, such as plastics, which are an increasingly prevalent wastewater contaminant. These micro-particles are not easily removed via conventional sedimentation and result in increased operation and maintenance costs in downstream unit processes. In this study, DMs were formed on a 90 µm supporting mesh through filtration of a synthetic wastewater. The impact of influent flux (solid flux) and influent particle concentration on DM performance was investigated. The effluent turbidity was reduced to <1 NTU after 20 mins of filtration, verifying the effective removal of micro-particles by the DM. Transmembrane pressure (TMP) and total filtration resistance increased linearly with filtration time, and were highly correlated (R2 > 0.998). TMP ranged from 80 to 180 mm of water head, and total filtration resistance ranged from 2.89 × 10-9 m-1 to 6.52 × 10-9 m-1 during DM filtration. In general, an increase in influent flux and influent particle concentration corresponds with increasing TMP and filtration resistance, as well as a rapid reduction in effluent turbidity due to swift formation of a DM on the supporting mesh.