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The practical application of Li-S batteries demands low cell balance (Licapacity /Scapacity ), which involves uniform Li growth, restrained shuttle effect, and fast redox reaction kinetics of S species simultaneously. Herein, with the aid of W2 C nanocrystals, a freestanding 3D current collector is applied as both Li and S hosts owing to its lithiophilic and sulfilic property. On the one hand, the highly conductive W2 C can reduce Li nucleation overpotentials, thus guiding uniform Li nucleation and deposition to suppress Li dendrite growth. On the other hand, the polar W2 C with catalytic effect can enhance the chemisorption affinity to lithium polysulfides (LiPSs) and guarantee fast redox kinetics to restrain S species in cathode region and promote the utilization of S. Surprisingly, a full Li-S battery with ultralow cell balance of 1.5:1 and high sulfur loading of 6.06 mg cm-2 shows obvious redox plateaus of S and maintains high reversible specific capacity of 1020 mAh g-1 (6.2 mAh cm-2 ) after 200 cycles. This work may shed new sights on the facile design of full Li-S battery with low excessive Li supply.

In the present study, a facile strategy to construct 3D vanadium nitride (VN)-decorated lotus root-like N-doping carbon nanofibers (VN-NCNFs) as current collector with stable electrochemical performance for Li-S batteries was described. The polar conductive VN with catalytic property provides chemical adsorption to trap lithium polysulfides (LiPSs) and enhances the transformation of LiPSs. The Li-S batteries with as-prepared VN-NCNFs current collector display stable cycling performance with a capacity of 700 mAh g−1 after 500 cycles at 0.2 C.

Vanadium carbide embedded in a nitrogen-doped carbon matrix (VC@NCM) is synthesized as a 3D freestanding sulfur host. Owing to the high electrical conductivity (1.6 × 104 S cm-1) of VC and strong chemisorption and catalytic effect on sulfur species, Li-S batteries with VC@NCM deliver enhanced redox kinetics with ultralow capacity decay of 0.01% per cycle after 1000 cycles at 1C. This work identifies the effect of strong chemisorption and high electrical conductivity on high S utilization and cycle stability in Li-S batteries.

The commercial course of Li-S batteries (LSBs) is impeded by several severe problems, such as low electrical conductivity of S, Li2 S2 , and Li2 S, considerable volume variation up to 80% during multiphase transformation and severe intermediation lithium polysulfides (LiPSs) shuttle effect. To solve above problems, conductive FeOOH interlayer is designed as an effective trapper and catalyst to accelerate the conversion of LiPSs in LSBs. FeOOH nanorod is effectively affinitive to S that Fe atoms act as Lewis acid sites to capture LiPSs via strong chemical anchoring capability and dispersion interaction. The excellent electrocatalytic effect enables that reduced charging potential barrier and enhanced electron/ion transport is realized on the FeOOH interlayer to promote LiPSs conversion. Significantly, Li2 S oxidation process is improved on the FeOOH interlayer determined as a combination of reduced Li2 S decomposition energy barrier and enhanced Li-ion transport. Therefore, the multifunctional FeOOH interlayer with conductive and catalytic features show strong chemisorption with LiPSs and accelerated LiPSs redox kinetics. As a result, LSBs with FeOOH interlayer displays high discharge capacity of 1449 mAh g-1 at 0.05 C and low capacity decay of 0.05% per cycle at 1 C, as well as excellent rate capability (449 mAh g-1 at 2 C).

Peanut shell, a widely available agricultural waste, was successfully grafted with quaternary ammine groups on its surface by using amination modification. The sorption mechanism of U(VI) on the amine cross-linked peanut shell (PNN) was examined by batch experiments and spectroscopy analysis. The physical adsorption was dominated by the liquid film diffusion and the intra-particle diffusion, whereas the chemical adsorption was dominated by surface complexation with quaternary amine groups and carboxyl groups. The maximum adsorption capacity of U(VI) on PNN was calculated to be 574.81 mg g−1 at pH = 6.0 and T = 298 K, which was much higher than that of U(VI) on pristine pure peanut shell and many other materials. Consideration of the high sorption efficiency and eco-friendliness of peanut shell, PNN presented promising potential in the preconcentration of radionuclides in radioactive pollution management.

The nanoscale zero valent iron (NZVI) modified coal fly ash (CFA) magnetic composites (NZVI/CFA) were synthesized from the waste CFA and applied for the high-efficiency sequestration of U(VI) ions from water solution. The sequestration capacity of U(VI) ions on NZVI/CFA (0.62 mmol·g−1) was larger than that on bare CFA (0.25 mmol·g−1) or NZVI (0.38 mmol·g−1). The sequestration of U(VI) on NZVI and NZVI/CFA was primary controlled by outer-sphere surface complexation at low pH, and by inner-sphere surface complexation at high pH. According to the thermodynamic data and the adsorption isotherms' analysis, the U(VI) sorption process to the NZVI/CFA was spontaneous and endothermic. The main reaction mechanism was that, most of the soluble U(VI) ions were firstly adsorbed to NZVI/CFA and then the surface adsorbed U(VI) was partly reduced to U(VI) on the porous NZVI/CFA composites, and this synergistically affected U(VI) removal from solution to NZVI/CFA. The results of DFT calculation indicated that the NZVI/CFA had a strong sequestration capacity towards U(VI) and U(IV) ions, and the binding energy of U(IV) species was larger than that of U(VI) species, which evidenced the higher sorption of U(IV) than U(VI) on NZVI/CFA. The results showed that NZVI/CFA was an appropriate material for U(VI) sequestration from large volumes of actual effluent in wastewater cleanup.

Concerns about the potential environmental risks of zinc oxide nanoparticles (ZnO NPs) are becoming an important issue because of their rapid growth in different fields. ZnO NPs are inevitably released in the environment during the production, transport, use and disposal process. Therefore, it is necessary to understand their toxicities and mode of actions. This review summarizes the toxic effects of ZnO NPs with different properties and exposed conditions on different species. The mechanisms of ZnO NPs on living organisms could be mainly attributed to one or more of the following aspects: the physical damage of direct contact, the dissolved zinc ions and the ROS-mediated mechanism. This paper systematically reviews the toxic effects of ZnO NPs on organisms and puts forward the existing problems, which are helpful for the safe and efficient use of ZnO NPs, providing the basis for further study of the toxic effects of ZnO NPs and establishing a comprehensive and safe evaluation system.

Germanium is considered as a potential anode material for sodium-ion batteries due to its fascinating theoretical specific capacity. However, its poor cyclability resulted from the sluggish kinetics and large volume change during repeated charge/discharge poses major threats for its further development. One solution is using its ternary compound as an alternative to improve the cycling stability. Here, high-purity CuGeO3 nanowires were prepared via a facile hydrothermal method, and their sodium storage performances were firstly explored. The as-obtained CuGeO3 delivered an initial charge capacity of 306.7 mAh g−1 along with favorable cycling performance, displaying great promise as a potential anode material for sodium ion batteries.

In this study, ternary Cu2SnS3 (CTS) nanostructure materials with high crystallinity were successfully prepared via a facile solvothermal method, which was followed by high-temperature treatment. The morphology of the as-synthesized samples is uniform flower-like spheres, with these spheres consisting of hierarchical nanosheets and possessing network features. Sodium storage measurements demonstrate that the annealed CTS electrodes have high initial reversible capacity (447.7 mAh&middot, g&minus, 1 at a current density of 100 mA&middot, 1), good capacity retention (200.6 mAh&middot, 1 after 50 cycles at a current density of 100 mA&middot, 1) and considerable rate capability because of their high crystallinity and unique morphology. Such good performances indicate that the high crystallinity CTS is a promising anode material for sodium ion batteries.