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The water evaporation rate of 3D solar evaporator heavily relies on the water transport height of the evaporator. In this work, a 3D solar evaporator featuring a soil capillary‐like structure is designed by surface coating native balsa wood using potassium hydroxide activated carbon (KAC). This KAC‐coated wood evaporator can transport water up to 32 cm, surpassing that of native wood by ≈8 times. Moreover, under 1 kW m−2 solar radiation without wind, the KAC‐coated wood evaporator exhibits a remarkable water evaporation rate of 25.3 kg m−2 h−1, ranking among the highest compared with other reported evaporators. The exceptional water transport capabilities of the KAC‐coated wood should be attributed to the black and hydrophilic KAC film, which creates a porous network resembling a soil capillary structure to facilitate efficient water transport. In the porous network of coated KAC film, the small internal pores play a pivotal role in achieving rapid capillary condensation, while the larger interstitial channels store condensed water, further promoting water transport up more and micropore capillary condensation. Moreover, this innovative design demonstrates efficacy in retarding phenol from wastewater through absorption onto the coated KAC film, thus presenting a new avenue for high‐efficiency clean water production. [ABSTRACT FROM AUTHOR]

Rational design of advanced electrolytes to improve the high‐voltage capability has been attracting wide attention as one critical solution to enable next‐generation high‐energy‐density batteries. However, the limited understanding of electrolyte antioxidant chemistry as well as the lack of valid quantization approaches have resulted in knowledge gap, which hinders the formulation of new electrolytes. Herein, we construct a standard curve based on representative solvation structures to quantify the oxidation stability of ether‐based electrolytes, which reveals the linear correlation between the oxidation potential and the atomic charge of the least oxidation‐resistant solvent. Dictated by the regularity between solvation composition and oxidation potential, a (Trifluoromethyl)cyclohexane‐based localized high‐concentration electrolyte dominated by anion‐less solvation structures was designed to optimize the cycling performance of 4.5 V 30 μm‐Li||3.8 mAh cm−2‐LiCoO2 batteries, which maintained 80 % capacity retention even after 440 cycles. The consistency of experimental and computational results validates the proposed principles, offering a fundamental guideline to evaluate and design aggressive electrochemical systems. [ABSTRACT FROM AUTHOR]

Pore modulation of carbon structures with low cost is of great importance for promoting the large-scale application of advanced supercapacitors. Herein, we innovatively propose a method for the directional preparation of hierarchical porous carbon materials using carbon aerogels assisted by mantis shrimp shells. The chitosan-based aerogel realizes self-assembly crosslinking in the mantis shrimp shell template possessing ordered pore arrays, with the template removed to obtain carbon materials with the corresponding pore structure after pre-carbonization, which is conducive to the full mixing of subsequent activators. The elimination of CaCO3 in the template and the further activation of carbon materials promote the formation of a porous structure. Thanks to the reasonable pore size distribution, high specific surface area and N/O doping of the carbon materials, a high specific capacitance of 401 F g−1 (0.5 A g−1) is achieved as an electrode material in a three-electrode system with 6 M KOH electrolyte. The pore distribution of the carbon materials at 0.5 and 0.8 nm enables the symmetric supercapacitors with the EMIMBF4 ionic liquid electrolyte to achieve an ultra-high energy density of 82.5 W h kg−1 (437.5 W kg−1). Further, the capacitance characteristics and ion diffusion rate are revealed in depth by Trasatti and Dunn's method as well as ion diffusion kinetic analysis. In addition, the transient distribution of electrolytes with different pore structures is simulated by COMSOL Multiphysics, which confirms that the hierarchical porous structure prepared with the assistance of mantis shrimp shells is more beneficial to the rapid diffusion of ions. [ABSTRACT FROM AUTHOR]

Electrolyte engineering advances Li metal batteries (LMBs) with high Coulombic efficiency (CE) by constructing LiF-rich solid electrolyte interphase (SEI). However, the low conductivity of LiF disturbs Li+ diffusion across SEI, thus inducing Li+ transfer-driven dendritic deposition. In this work, we establish a mechanistic model to decipher how the SEI affects Li plating in high-fluorine electrolytes. The presented theory depicts a linear correlation between the capacity loss and current density to identify the slope k (determined by Li+ mobility of SEI components) as an indicator for describing the homogeneity of Li+ flux across SEI, while the intercept dictates the maximum CE that electrolytes can achieve. This model inspires the design of an efficient electrolyte that generates dual-halide SEI to homogenize Li+ distribution and Li deposition. The model-driven protocol offers a promising energetic analysis to evaluate the compatibility of electrolytes to Li anode, thus guiding the design of promising electrolytes for LMBs. The low conductivity of LiF disturbs Li+ diffusion across solid electrolyte interphase (SEI) and induces Li+ transfer-driven dendritic growth. Herein, the authors establish a mechanistic model to decipher how the SEI affects realistic Li plating in high-fluorine electrolytes. [ABSTRACT FROM AUTHOR]

The solar-driven interfacial photothermal evaporation-based water purification process has become a promising sustainable strategy for clean water production. However, conventional evaporation-based solar purification suffers from the limited efficiency of the subsequent vapor collection due to the very low heat dissipation from the vapor to the outside ambient air. Here, we designed an efficient vapor condensation device via dissipating the heat mainly to a metal Al array-based condenser and finally to bottom bulk water. As the metal Al and bottom bulk water have thermal transfer capabilities that are tens to hundreds of times greater than those of the cooling medium air and glass cover in the conventional device, we achieved a greatly enhanced vapor condensation rate of 1.16 kg m−2 h−1 (0.8 kW m−2) with a vapor collection efficiency of 75.7%. Our bottom bulk water cooling device can stably generate clean water during a nine-day continuous self-floating experiment on a lake surface, with a water generation rate of around 8.09 kg m−2 d−1, indicating that it represents a passive and simple device for practical water supplementation via direct placement and self-floating on the surface of a body of water. [ABSTRACT FROM AUTHOR]

Novel biocomposite aerogels with Janus character are fabricated for application as interfacial evaporators, using cellulose nanofibrils (CNFs) as building blocks and Ti3C2Tx MXenes as functional fillers via pre-freezing, solvent exchange, unidirectional freeze-casting, and freeze-drying. The upper and lower parts of the Janus CNF/MXene composite aerogels (JCM aerogels) exhibit opposite wettabilities and perform complementary functions. The lower part of the aerogel is a hydrophilic CNF aerogel for enabling continuous upward water transport. The function of the upper part, a silane-modified hydrophobic CNF/MXene aerogel, is photothermal conversion and heat insulation for efficient evaporation of water. The JCM aerogels self-float stably on the water surface and achieve a high evaporation rate of 2.287 kg m−2 h−1 at an efficiency of 88.2% under 1 sun illumination. Numerical simulations for heat and mass transfer confirm the synergy between the two parts of the composites, which enabled the excellent evaporation performance observed. In addition, the JCM aerogels showed excellent salt resistance and seawater durability in simulated solar-driven desalination experiments. The design of these interfacial evaporators may offer new insights for developing reliable and environmentally friendly water purification technologies. [ABSTRACT FROM AUTHOR]

Abstract: Quenching experiments with copper spheres were performed to characterize the transient pool boiling of aqueous nanofluids in the presence of graphene oxide nanosheets (GONs) at various dilute concentrations (⩽0.001wt.%). The CHF enhancement was found to vary non-monotonously with increasing the concentration of GONs. This non-monotonic variation was in accordance with the surface wettability change due to the deposited GONs after quenching. In addition to the primary effect of the deposition layers, the non-negligible influence of the suspended GONs was also identified, especially at relatively higher concentrations. [Copyright &y& Elsevier]

Abstract: Three-dimensional transient thermal analyses of an air-cooled module that contains prismatic lithium-ion cells operating under an aggressive driving profile were performed using a commercial computational fluid dynamics code. The existing module utilized air cooling through evenly-spaced channels on both sides of each cell. It was found that lowering the gap spacing and/or higher flow rate of the fan lead to a decrease of the maximum temperature rise. To achieve improved temperature uniformity over the module, the gap spacing should be of a moderate size. For the given module, operating with a uniform gap spacing of 3 mm and an air flow rate of 40.8 m3 h−1 appears to be the best choice that satisfies the trade-off requirements of the fan power, maximum temperature rise and temperature uniformity. Using the same gap spacing and air flow rate, a proposed design of one-side cooling is less effective than two-side cooling. Uneven gap spacing affects the temperature distributions, but it does not impact the maximum temperature rise markedly. Considering the variety of the design change options and their combinations, it is concluded that the temperature gradients along the air flow direction can be affected but are generally unavoidable. [Copyright &y& Elsevier]

Low thermal conductivity and leakage after melting are the two main issues limited the application of phase change materials (PCMs). Here, to improve the thermal conductivity and hamper the leakage after melting, PCMs were fabricated by infiltrating paraffin into h-BN porous scaffolds with continuous thermal conductive paths. The latent heat of fusion of the resultant PCMs containing 18 wt% h-BN was 165.4 ± 1.7 J/g, and the thermal conductivity was as high as 0.85 W/mK. The thermal conductivity increased approximately 600% compared to the pure paraffin, and was over twice of the composites fabricated by conventional blending of paraffin and h-BN. The enhanced thermal conductivity obviously shortened the phase change process, indicating more efficient in energy storage and release. In addition, the h-BN scaffolds endowed the PCMs shape stability under molten state and prevented the leakage of molten paraffin. This approach to fabricate form-stable PCMs with high thermal conductivity may extend to other thermal management applications. [ABSTRACT FROM AUTHOR]

A hybrid energy system including both off-site and distributed energy sources, energy conversion technologies and operation methods, is a necessary step on a transition path towards a sustainable energy system. The challenge is to identify such a combination of design options that result in minimum life cycle cost (LCC) and maximum exergy efficiency (EE) at each phase of the transition path. In this paper, a time-effective multi-objective optimization method based on genetic algorithm (GA), is proposed for the transition path problem. The proposed model makes use of a fitness function approach to reduce the model into one objective function and to reduce the computational time. In a case study, the model is applied to a potential net-zero exergy district (NZEXD) in Hangzhou, China. Here, three possible hybrid energy scenarios and three preference treatment strategies are analyzed. The study suggests that the proposed approach is workable for the identification of the most feasible options to be gradually integrated in an NZEXD in a multi-stage process. In the Hangzhou case, with the reduction of investments in distributed energy components and escalating market prices of fossil fuels, distributed energy system (DES) may have more feasibility in the near future. [ABSTRACT FROM AUTHOR]