Toward Forty Thousand-Cycle Aqueous Zinc-Iodine Battery: Simultaneously Inhibiting Polyiodides Shuttle and Stabilizing Zinc Anode through a Suspension Electrolyte

Aqueous zinc-iodine (Zn-I₂) batteries are promising candidates for grid-scale energy storage due to their safety and cost-effectiveness. However, the shuttle effect of polyiodides, Zn corrosion, and accumulation of by-products restrict their applications. Herein, a simple vermiculite nanosheets (VS) suspension electrolyte is designed for simultaneous confinement of polyiodides and stabilization of Zn anode. It is found that the generation of I₅⁻ as dominant intermediate and the precipitation reaction between I₅⁻ and alkaline by-products should cause irreversible iodine species loss. Benefiting from the high binding energy between polyiodides and silica-oxygen bonds of VS, dissolved polyiodides are effectively anchored on the surface of VS suspended in the bulk electrolyte to suppress the shuttle effect, which is confirmed by in situ Raman, Ultraviolet-visible characterizations and theoretical calculations. Furthermore, the self-assembly VS interfacial layer on the surface of Zn anode hinders side reactions induced by polyiodides. Meanwhile, the interlayer and surface excess negative charges of VS tend to be compensated by Zn²⁺ from diffuse layer, which serves as ion accelerators for transferring Zn²⁺ at the interface immediately, rendering dendrite-free Zn plating/stripping behavior. Consequently, the Zn-I₂ battery with VS electrolyte achieves an ultra-long lifespan of 40000 cycles with a negligible capacity decay at 20 C.     

Topology and porosity control on zirconium–fumarate frameworks boosting xenon/krypton separation

The designability and ultrahigh stability of zirconium–organic frameworks make them attractive adsorbents for noble gases xenon (Xe) and krypton (Kr), but their Xe/Kr separation performance needs to be further enhanced. In this study, we rationally control the topology and porosity of zirconium–fumarate frameworks by simply changing the synthesis conditions, and successfully construct an adsorbent (named as MIP-203-F) with one-dimensional pore instead of the original cage-like fcu metal–organic framework MOF-801. The Xe/Kr separation performance of MIP-203-F is thoroughly evaluated by isotherm measurements and breakthrough experiments, while the adsorption mechanism is elucidated in detail by Monte Carlo and density functional theory calculations. Due to the uniform pore with suitable size and abundant polarization groups, MIP-203-F can differentially polarize and recognize atomic Xe/Kr gases, and establishes a new record among zirconium–organic frameworks for the capture and separation of Xe/Kr.     

Ni对高碳工具钢75Cr1组织和性能的影响

为开发高性能、长寿命的木工圆锯片、带锯条、弹簧等五金工具，在75Cr1钢中分别添加质量分数为0.2%、0.4%的Ni元素。通过力学性能检验、显微组织分析以及热处理试验，研究了不同Ni含量对75Cr1钢热轧态及热处理态力学性能与显微组织的影响。结果表明，在Ni添加量为0%～0.4%的范围内，能降低热轧75Cr1钢的强度与硬度，提高塑性，其含量越高，效果越显著，但对冲击性能影响不明显；Ni对淬火硬度影响不大，当Ni含量达到0.4%时，硬度呈降低趋势，但明显提高回火后的塑性，降低回火后的强度与硬度，并改善回火后的冲击吸收能量，Ni含量越高，改善效果越明显。显微组织方面，Ni可以细化热轧75Cr1钢珠光体球团尺寸及片层间距，促进珠光体片的球化，同时也细化淬火与回火后的显微组织。结合经济性与综合力学性能考虑，75Cr1钢中Ni的最佳添加量为0.2%。     

Water-Assisted Growth of Twisted 3R-Stacked MoSe2 Spirals and Its Dramatically Enhanced Second Harmonic Generations

Enhanced second-harmonic generation (SHG) responses are reported in monolayer transition metal dichalcogenides (e.g., MX₂, M: Mo, W; X: S, Se) due to the broken symmetries. The 3R-like stacked MX₂ spiral structures possessing the similar broken inversion symmetry should present dramatically enhanced SHG responses, thus providing great flexibility in designing miniaturized on-chip nonlinear optical devices. To achieve this, the first direct synthesis of twisted 3R-stacked chiral molybdenum diselenide (MoSe₂) spiral structures with specific screw dislocations (SD) arms is reported, via designing a water-assisted chemical vapor transport (CVT) approach. The study also clarifies the formation mechanism of the MoSe₂ spiral structures, by precisely regulating the precursor supply accompanying with multiscale characterizations. Significantly, an up to three orders of magnitude enhancement of the SHG responses in twisted 3R stacked MoSe₂ spirals is demonstrated, which is proposed to arise from the synergistic effects of broken inversion symmetry, strong light–matter interaction, and band nesting effects. Briefly, the work provides an efficient synthetic route for achieving the 3R-stacked TMDCs spirals, which can serve as perfect platforms for promoting their applications in on-chip nonlinear optical devices.     

非油炸果蔬脆片生产的新技术

概述了ＣＯ２膨化果蔬脆片技术的发展概况、原理。并对此项技术的工艺流程、技术要点及其发展前景进行了展望。     

Facile and Scalable Mechanochemical Synthesis of Defective MoS2 with Ru Single Atoms Toward High-Current-Density Hydrogen Evolution

Designing a facile strategy to prepare catalysts with highly active sites are challenging for large-scale implementation of electrochemical hydrogen production. Herein, a straightforward and eco-friendly method by high-energy mechanochemical ball milling for mass production of atomic Ru dispersive in defective MoS₂ catalysts (Ru₁@D-MoS₂) is developed. It is found that single atomic Ru doping induces the generation of S vacancies, which can break the electronic neutrality around Ru atoms, leading to an asymmetrical distribution of electrons. It is also demonstrated that the Ru₁@D-MoS₂ exhibits superb alkaline hydrogen evolution enhancement, possibly attributing to this electronic asymmetry. The overpotential required to deliver a current density of 10 mA cm⁻² is as low as 107 mV, which is much lower than that of commercial MoS₂ (C-MoS₂, 364 mV). Further density functional theory (DFT) calculations also support that the vacancy-coupled single Ru enables much higher electronic distribution asymmetry degree, which could regulate the adsorption energy of intermediates, favoring the water dissociation and the adsorption/desorption of H*. Besides, the long-term stability test under 500 mA cm⁻² further confirms the robust performance of Ru₁@D-MoS₂. Our strategy provides a promising and practical way towards large-scale preparation of advanced HER catalysts for commercial applications.     

Influence of dielectric barrier effect and thermally-conductive network on thermal and electrical properties of epoxy under different frequencies and temperatures

Epoxy resin (EPR) insulations play a vital role in the insulation of modern power electronic equipment owing to their excellent dielectric properties. However, due to the high-power density and miniaturization of power equipment which causes high heat fluxes under high voltage and high-frequency stresses, EPR with good thermal and insulation properties is urgently needed. In this study, the polydopamine functionalized micro-BN and core-shell nano TiO₂–SiO₂ particles are dispersed in EPR to simultaneously improve thermal and dielectric insulation properties. It is revealed that the addition of micro-nano particles significantly improves the thermal and dielectric performance. Particularly, the high thermal conductivity of micro-BN and the dielectric barrier effect due to the core-shell structure of nano TiO₂–SiO₂ are the main reasons for improved thermal and dielectric insulation performance, respectively. The EPR composite containing 3 wt% of micro-BN and 1 wt% of nano TiO₂–SiO₂ exhibits the optimal performance with 0.49 W/mK thermal conductivity and the highest dielectric strength among all the samples, that is, 60.61 kV/mm even at 10 kHz and 90°C. This study found that the crucial factors are the surface encapsulation, weight percent, and homogeneous dispersion of particles in EPR, the dielectric barrier effect, thermal conductivity, and the mismatch between the dielectric constant of EPR and particles. This study proposes the optimal weight percent of suitable micro-nano particles for EPR to produce suitable composites for high-frequency and high-temperature applications.