Solid polymer electrolytes have emerged as promising alternatives to current liquid electrolytes due to their advantages in battery safety and stability. Among various polymer electrolytes, poly(vinylidene fluoride) (PVDF)‐based electrolytes with high ionic conductivity, large mechanical strength, and excellent electrochemical and thermal stability have a great potential for practical applications. However, fundamental issues, such as how the Li ions transport in the PVDF‐based electrolytes and how the residual solvent affects the cell performance, are unclear. Here, we demonstrate that the solvation effect due to a small amount of residual N,N‐dimethylformamide (DMF) bound into the electrolytes plays a critical role in ionic transport, interface stability, and cell performance. With the residual DMF existing in the electrolytes in a bound state not as free solvent, the ionic conduction could be realized by the Li‐ion transport among the interaction sites between the bound DMF and PVDF chains. Regulating the solvation effect in the electrolytes can make the PVDF‐based solid‐state Li metal batteries a significantly improved cycling performance at 25 °C (e. g., over 1000 cycles with a capacity retention of more than 94 %). These findings would promote the development of next‐generation Li metal batteries with high energy density and safety.
The ability to dictate the assembly of quantum dots (QDs) is critical for their integration into solid-state electronic and optoelectronic devices. However, assembly methods that enable efficient electronic communication between QDs, facilitate access to the reactive surface, and retain the native quantum confinement characteristics of the QD are lacking. Here we introduce a universal and facile electrochemical gelation method for assembling metal chalcogenide QDs (as demonstrated for CdS, ZnS, and CdSe) into macroscale 3-D connected pore-matter nanoarchitectures that remain quantum confined and in which each QD is accessible to the ambient. Because of the redox-active nature of the bonding between QD building blocks in the gel network, the electrogelation process is reversible. We further demonstrate the application of this electrogelation method for a one-step fabrication of CdS gel gas sensors, producing devices with exceptional performance for NO2 gas sensing at room temperature, thereby enabling the development of low-cost, sensitive, and reliable devices for air quality monitoring.
(2 of 12)electrodes, low Coulombic Efficiency, and severe capacity decay. Therefore, developing remarkable components of batteries for addressing these challenges is significantly urgent. Separators, as the bridge between cathode and anode presented on electrolyte, exhibit considerable potential in simultaneously retarding the negative effect of LiPSs to cathode and anode. [11][12][13][14] Nevertheless, it is difficult for the traditional polypropylene (PP) separator to promote the adsorption and conversion of LiPSs, which is ascribed to its electronic insulativity. [15] Impressively, the introduction of active materials with outstanding catalytic performance as separator coatings can boost the kinetical conversion between LiPSs and Li 2 S 2 /Li 2 S, and propel adsorption to LiPSs for relieving shuttle effect, which is regarded as a suitable route to construct high-performance Li-S batteries.Single-atom catalysts (SACs) play a vital role in the energy and catalysis fields as they are characterized to be almost 100% atomic utilization and unique electronic structure, showing great prospect in high-performance Li-S batteries. [16][17][18][19][20][21][22] The catalytic performance of SACs is extremely dependent on the local microenvironments of central metal, that is, the local coordination configuration involving coordination atoms species, number, and bond length. [23][24][25] Up to now, the reported SACs to improve Li-S batteries mainly focus on the conventional metal-nitrogen-carbon catalysts supported on carbon-based supports; however, the nonpolar metal-N 4 coordination is difficult to efficiently absorb LiPSs. [10,15] Recently, both theoretical and experimental reports suggest that asymmetrically coordinated environment of SACs may highly influence the catalytic performance, which is attributed to the disordered electronic redistribution and irregular geometric structure optimizing the adsorption and conversion for intermediates. [26][27][28] However, the tunable asymmetrical coordination of central metal atoms to kinetically accelerate LiPSs conversion and strengthen LiPSs adsorption for ultrastable Li-S batteries has barely been reported. Thus, the delicate construction of isolated metal sites on ideal supports with asymmetrically coordinated configuration to meet high-efficiency requirement is promising but challenging for Li-S batteries.MXenes, emerging 2D materials, represent the novel family of transition metal carbides, nitrides, or carbon nitrides. [29][30][31] The general formula of MXenes is M n+1 X n T x , where M means the transition metal, X represents the C and/or N elements, and T x represents the surface groups (O, OH, F, and so on), reflecting its compositional variability. [32][33][34][35] Benefitting from
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