Aqueous zinc-ion batteries (ZIBs) have garnered widespread interest owing to their merits of high safety and low cost. Nevertheless, the commercial application of ZIBs is hindered by uncontrollable dendrite growth and adverse side reactions. Herein, a potential spontaneous reducing and assembling strategy has been tailored to generate a uniform and ultra-thin layer of sulfonate modified Mxene (SM-MXene) layer on the Zn surface to regulate electrochemical behavior. Compared with the bare Zn foil, the optimizing SM-MXene layer has an advantageous charge redistribution effect, resulting in a uniform electric field and a lower Zn nucleation energy barrier. The SM-MXene layer can also block the entry of H2O and inhibit the severe side reactions. The zincophilic SM-MXene layer, possessing abundant sulfonic acid groups (- SO3H), can remarkably reduce the surface energy of the Zn (002) crystal plane and induce the preferential growth of (002) horizontally orientation during the electrodeposition process, resulting in highly reversible process between Zn plating and stripping with dendrite-free and corrosion-free behaviors. Accordingly, the symmetric battery, using SM-MXene/ZnSO4 as electrolyte, exhibits ultra-high Coulombic efficiency (99.48 %) and ultra-long cycle life (over 5000 cycles), subsequently enabling the Zn||MnO2 full cell highly rechargeable.

Adverse side reactions and uncontrolled Zn dendrites growth are the dominant factors that have restricted the application of Zn ion batteries. Herein, a 3D self-supporting porous carbon fibers (denoted as PCFs) host is developed with "trap" effect to adjust the Zn deposition. The unique open structural design of N-doped carbon can act as the zincophilic sites to induce uniform deposition and inhibit adverse side reactions. More importantly, the porous hollow PCFs host with "trap" effect can induce Zn deposition in the fiber by adjusting the local electric field and current density, thereby increasing the specific energy density of the battery and inhibiting dendrite growth. In addition, the 3D open frameworks can regulate Zn2+ flux to enable outstanding cycling performance at ultra-high current densities. As expected, the PCFs framework guarantees the uniform Zn plating and stripping with an outstanding stability over 6000 cycles at the current density of 40 mA cm(-2). And the Zn@PCFs||MnO2 full battery shows an excellent lifespan over 1300 cycles at 2000 mA g(-1).

Precise design and tuning of Zn hopping/transfer sites with deeper understanding of the dendrite-formation mechanism is vital in artificial anode protective coating for aqueous Zn-ion batteries (AZIBs). Here, we probe into the role of anode-coating interfaces by designing a series of anhydride-based covalent organic frameworks (i.e., PI-DP-COF and PI-DT-COF) with specifically designed zigzag hopping sites and zincophilic anhydride groups that can serve as desired platforms to investigate the related Zn 2+ hopping/transfer behaviours as well as the interfacial interaction. Combining theoretical calculations with experiments, the ABC stacking models of these COFs endow the structures with specific zigzag sites along the 1D channel that can accelerate Zn 2+ transfer kinetics, lower surface-energy, homogenize ion-distribution or electric-filed. Attributed to these superiorities, thus-obtained optimal PI-DT-COF cells offer excellent cycling lifespan in both symmetric-cell (2000 cycles at 60 mA cm −2 ) and full-cell (1600 cycles at 2 A g −1 ), outperforming almost all the reported porous crystalline materials.

The inhomogeneous consumption of anions and direct contact between electrolyte and anode during the Zn-deposition process generate Zn-dendrites and side reactions that can aggravate the space-charge effect to hinder the practical implementation of zinc-metal batteries (ZMBs). Herein, electrospray has been applied for the scalable fabrication (>10 000 cm 2 in a batch-experiment) of hetero-metallic cluster covalent-organic-frameworks (MCOF-Ti 6 Cu 3 ) nanosheet-coating (MNC) with integrated micro space electrostatic field for ZMBs anode protection. The MNC@Zn symmetric cell presents ultralow overpotential (≈72.8 mV) over 10 000 cycles at 1 mAh cm −2 with 20 mA cm −2 , which is superior to bare Zn and state-of-the-art porous crystalline materials. Theoretical calculations reveal that MNC with integrated micro space electrostatic field can facilitate the deposition-kinetic and homogenize the electric field of anode to significantly promote the lifespan of ZMBs.

Anisotropically hybridized porous crystalline Li-S battery separators based on porous crystalline materials that can meet the multiple functionalities of both anodic and cathodic sides are much desired for Li-S battery yet still challenging in directional design. Here, an anisotropically hybridized separator (CPM) based on an ionic liquid-modified porphyrin-based covalent-organic framework (COF-366-OH-IL) and catalytically active metal-organic framework (Ni3 (HITP)2 ) that can integrate the lithium-polysulfides (LiPSs) adsorption/catalytic conversion and ion-conduction sites together to directionally meet the requirements of electrodes is reported. Remarkably, the-obtained separator exhibits an exceptional high Li+ transference-number (tLi+ = 0.8), ultralow polarization-voltage (<30 mV), high initial specific-capacity (921.38 mAh g-1 at 1 C), and stable cycling-performance, much superior to polypropylene and monolayer-modified separators. Moreover, theoretical calculations confirm the anisotropic effect of CPM on the anodic side (e.g., Li+ transfer, LiPSs adsorption, and anode-protection) and cathodic side (e.g., LiPSs adsorption/catalysis). This work might provide a new perspective for separator exploration.

Zn metal batteries have garnered considerable scientific and technological interests. However, the widespread commercial application of these batteries is impeded by the uncontrollable dendrite growth and consequent severe side effects. Herein, a functionalized separator is prepared by spraying polyaniline‐modified graphene oxide (denoted as NPGO)/polyvinylidene difluoride solution directly on one side of a common separator of glass fibers (GFs). The reversible transition between protonated and deprotonated states of quinolone imide on NPGO nanosheets can facilitate the rapid desolvation and transfer of Zn 2+ . Therefore, the spatial electric field as well as the Zn 2+ flux is effectively homogenized due to the ion‐sieving effect of NPGO nanosheets that are oriented toward Zn anode. This engineering design of the NPGO@GFs separator harvests excellent rate and cycling performance (over 3000 cycles at 20 mA cm −2 ) for Zn metal symmetric batteries. Meanwhile, it provides an impressive commercial prospect (500 cycles with a capacity retention of 91.6% under 2000 mA g −1 ) for MnO 2 ||Zn full batteries. Such a strategy can be generalized as a common way to protect metal anodes (Na, Zn, and K) in rechargeable batteries, which is highly cost‐effective and scalable.

Zn-based aqueous batteries have attracted much attention because of their high theoretical-capacity, safety, and low-cost, yet the H-2-evolution, qualification or inhibition mechanism investigations that are closely related to the dendrite-growth are rare and challenging. Herein, a series of zincophilic metal-covalent organic frameworks (e.g., Zn-AAn-COF, Zn-DAAQ-COF, and Zn-DAA-COF) have been explored as model-platforms to manipulate the H-2-evolution and Zn2+ flux. Best of them, Zn-AAn-COF based cell only produces 0.002 mmol h(-1) cm(-2) H-2, which is >2 orders of magnitude lower than bare Zn. Noteworthy, it affords high stability for 3000 cycles (overpotential, <79.1 mV) at 20 mA cm(-2) in symmetric-cell and enhanced cycling-stability up to 6000 cycles at 2000 mAg(-1) in the assembled full-battery. Besides, mechanistic characterizations show that Zn-AAn-COF can enhance the energy-barrier of H-2-evolution and homogenize the ion-distribution or electric-filed to achieve high performance.

Biomimetic construction of artificial photosystem capable of converting light energy to chemical energy is a promising strategy in solving the increasing serious energy and environmental problems. Herein, we present a new strategy to construct light-harvesting antenna via hierarchical co-assembly of short peptide and porphyrin and subsequent self-metallization process. The hierarchically organized antenna exhibits both excellent photocatalytic performance and remarkable sustainability under strong light irradiation (35000 lx) and extraordinary sensitivity to weak light (700 lx). In such cases, light energy can be converted into chemical energy and stored in the energy-storage molecules (nicotinamide adenine dinucleotide, NADH) even under weak light irradiation. This provides a promising step towards an artificial photosystem that can utilize weak light. Moreover, the structures and properties of the antenna are dependent on the competition of short-peptide self-assembling and co-assembling with porphyrin molecules and can be regulated by their molar ratio. This provides new insights into the design and construction of light-harvesting antennas with integrated functionality via precise control of pigments aggregation and coupling of different functional units. (c) 2020 Elsevier Inc. All rights reserved.