[en] Highlights: • We have studied the anchong effects of two-dimensional Ti_2CO_2 monolayer for Li-S batteries. • Ti_2CO_2 monolayer can strongly interact with Li_2S_n species with moderate binding strength to effectively immobilize the soluble polysulfides. • The intactness of the Li_2S_n species can be well saved. - Abstract: The large-scale practical application of lithium-sulfur (Li-S) batteries cannot be relized unless the challenge of dissolving of soluble lithium polysulfides (Li_2S_n) species in electrolytes can be solved. Herein, by means of density functional theory (DFT) computations, we systematically exploited the anchoring effects of various titanium carbide-based MXenes for Li-S batteries. Our results revealed that, due to the attraction between Li ions in Li_2S_n species and O atoms in Ti_2CO_2 and Ti_3C_2O_2 monolayer, the two Mxenes can strongly interact with Li_2S_n species with remarkable but not too strong binding strength to effectively immobilize the soluble polysulfides. Especially, the intactness of the Li_2S_n species can be well saved, although the Li−S bonds are weakened. Therefore, Ti_2CO_2 and Ti_3C_2O_2 monolayers are quite promising anchoring materials with good cycling performances for Li-S batteries.

[en] A novel 3-DOF Leg mechanism (LM), which consists of a 2RUS+RU PM, a space parallelogram mechanism and a connecting spherical joint is proposed. The LM has good protective characteristics. The whole LM is driven by the 2RUS+RU PM. The kinematics formulae and the inertial force formulae at their mass centers of moving links are derived. Based on the principle of virtue work, the dynamics formula is built for solving the dynamic driving force of the LM. An analytic example on the kinematics and dynamics is given. The kinematics and dynamics results of the example are verified by a simulation model of the LM. On the basis of the kinematics results, motion characteristics of the LM are analyzed and the leg layout of the robot is determined. The LM is improved according to the dynamics results. The dynamic model of improved LM is established. The workspace of improved LM is drawn

[en] Highlights: • Polyvinyl alcohol (PVA) can be an effective protection layer for Li metal anode. • PVA participated in formation of a stable composite SEI layer for Li metal anode. • Dendrite-free Li deposition and alleviated electrolyte consumption by the PVA layer. • Stable cycling of Li–S, Li-LFP or Li-NCM cells by PVA-protected Li metal anodes. -- Abstract: Lithium (Li) metal is considered an ideal anode for next-generation high energy Li metal batteries (LMBs) due to its high theoretical specific capacity and low electrochemical potential. However, stable cycling of LMBs has long been restrained by the extremely unstable interfaces between the Li metal anode and liquid electrolyte. Here, we found that low-cost polyvinyl alcohol (PVA) polymer can be applied as an effective protection layer for Li metal anodes in both ether- and carbonate-based electrolytes. The PVA protection layer will participate in and facilitate formation of a superior PVA-modified solid electrolyte interphase (SEI) layer on Li metal, leading to uniform deposition of Li and alleviated consumption of electrolyte. Li||Cu half-cells with the PVA protection layers show dendrite-free Li deposition and greatly extended stable cycling with high Coulombic efficiency (CE) (e.g. average CE of 98.3% for over 630 cycles). Li-Sulfur, Li–LiFePO₄ and Li–LiNi_0.6Co_0.2Mn_0.2O₂ full-cells using the PVA-protected Li metal anodes also show significantly improved electrochemical performance with better capacity retention and higher CE, even under lean electrolyte (7.5 μL mAh⁻¹) condition.

[en] Highlights: • A electro-hydraulic energy-saving system is proposed for energy recovery and regeneration. • A parametric rule-based strategy of the proposed system is developed for real-time control. • The proposed energy-saving system prototype is equipped on a 23-ton hydraulic excavator. • Experiments studies show that about 17.6% energy can be saving by this system. • The system is evaluated from multiple perspectives of efficiency, performance and comfort. -- Abstract: Energy recovery and regeneration comprise an effective way to improve hydraulic excavator fuel economy. This paper proposes a novel electro-hydraulic energy-saving system to integrate recovery and regeneration devices. The working conditions of excavators and system configuration of the proposed system are analyzed. A parametric rule-based strategy is implemented to real-time control. A energy-saving prototype is developed for a 23-ton hydraulic excavator. Several tests are carried out to evaluate the prototype from the perspectives of energy consumption, action performance, and system comfortableness. Results show that the excavator equipped with the energy-saving system can be reduced by approximately 17.6% compared with a conventional one. The braking time of the boom-lowering process is about 1.87 times that of the conventional system. The electric motor is the main vibration source, and the impact of hydraulic system shock on comfortableness is indirect. The results are important reference for further system optimization.

[en] Highlights: • Identification of two types of microplastic-oil-dispersant agglomerates (MODAs). • First report of MODA formation mechanism in the marine environment. • Dispersants could change MODA morphology and size distribution. • MODA reduced oil dispersion effectiveness under various mixing energy and salinities. • MODA-1 would cause a larger reduction in oil dispersion effectiveness than MODA-2. Microplastics (MPs) can interact with spilled oil to form MP-oil-dispersant agglomerates (MODAs) in oceans. This study investigated the MODA formation mechanism and its impact on oil dispersion during marine oil spill responses. Two types of agglomerates, MODA-1 (MP-in-oil) and MODA-2 (MP-oil droplet-embedded), were identified. The 12 µm-MPs only formed MODA-1, while 45 µm-MPs and 125 µm-MPs formed MODA-1 and MODA-2 due to the surface free energy minimization principle. Impacts of MODA on oil dispersion under different mixing energy levels and seawater salinities were explored. We found that MODA reduced oil dispersion effectiveness under different mixing energy levels. Among three MP sizes, 12 µm-MPs caused the greatest reduction in dispersion effectiveness due to the formation of MODA-1. Pristine 12 µm-MPs reduced dispersion effectiveness by 21.95% under 5.62 × 10⁻¹ W/kg, while pristine 45 µm-MPs and pristine 125 µm-MPs decreased it by 5.85% and 1.83%, respectively. In addition, MODA formed by pristine MPs has a larger impact on oil dispersion effectiveness than that of aged MPs under different salinities. Under 20psu, pristine 12 µm-MPs reduced dispersion effectiveness by 33.68%, while aged 12 µm-MPs decreased it by 24.61%. This study is the first report on the MODA formation mechanism, which is essential for exploring MODA transport and toxicity through marine trophic levels.