The synthesis of a block codendrimer (g3-PBE-b-g3-PMDC), composed of a third-generation poly(benzyl ether) (PBE) monodendron and an aliphatic polyether (PMDC) monodendron is reported. In THF/diiospropyl ether (1:1) the PMDC block functions as a "hydrophilic" block, while the PBE acts as a "hydrophobic" block. The codendrimer can form interdigitated layers leading to vesicle formation. Tapping mode atomic force microscopy (AFM), dynamic light scattering (DLS), and transmission electron microscopy (TEM) were used to characterize the vesicles. The effect of molecular architecture on the formation of the interdigitated layers and vesicles was studied.

Crystalline macromolecules form folded-chain lamellar and metastable crystals. Annealing at a temperature below melting point results in a thickening of the metastable crystals to construct more stable ones. Such a process was visualized by AFM equipped with a hot stage in monolayers of poly(ethylene oxide) lamellar crystals on a silicon wafer surface. Our observations show that the monolayers can be thickened in a stepwise manner during stepwise heating to temperatures below the melting point. Our analyses show the thickening process and mechanism as follows:  At the first step a small portion of the lamellar crystals have the capability to be spontaneously thickened into a thicker one at a certain temperature range, giving rise to a difference in lamellar thickness. In the following step the thinner lamellae are forced to melt, and then the melted molecules enter an amorphous phase in which they are transported toward the thicker lamellae and finally recrystallize in the thicker ones. This inductive mechanism is analogous to the evaporation−condensation mechanism.

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Defects engineering is an attractive strategy to improve the potassium storage performance of carbon anodes. The current studies mainly focus on the introduction of external defects via heteroatom doping, however, the exploration on the effect of intrinsic defects caused by the loss of atoms or distortion in the crystal lattice on potassium storage is still lacking to date. Hence, a series of carbon materials with different intrinsic defect levels are developed via a soft-template assisted method. It is found that intrinsic defects content in carbon is synergistically determined by the application of template and pyrolysis temperature, and a higher defects content is more likely to expose enormous edge active sites. This greatly promotes K-adsorption storage during surface-induced capacitive process, and therefore a strong positive correlation between capacity/capacity retention and intrinsic defects content is confirmed. As a result, the electrode with maximum defects content realizes a good capacity and a rate capability with long cycle lifespan (225.9 mAh g −1 at 2 A g −1 over 2000 cycles). This study offers an insight into the role of intrinsic defects of carbon materials in potassium storage performance.

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greatly limits the further large-scale application of LIBs. [5][6][7][8] Therefore, it is quite important to explore alternative energy storage technologies with low cost and high electrochemical performance beyond LIBs for a sustainable development. Toward this end, potassium-ion batteries (PIBs) are recognized as one of the most promising candidates for the next-generation energy storage devices, owing to their advantages of abundant resources, low cost, and high interface diffusion. [9][10][11] More importantly, PIBs have a potential to achieve high work voltage and energy density because the redox potential of K/ K + (−2.93 V vs Standard Hydrogen Electrode (SHE)) is much closer to that of Li/ Li + (−3.04 V vs SHE). [3,12,13] Attracted by these merits, much effort has been made to design and fabricate high-performance PIBs.In spite of the similarity of PIBs to LIBs, however, numerous well-established electrode materials in LIBs cannot be directly applied in PIBs owing to the larger ionic size of K + (1.38 Å) in comparison with Li + (0.76 Å). [14,15] Particularly, commercial graphite anode can only exhibit a theoretical specific capacity of 279 mAh g −1 for PIBs, much lower than 372 mAh g −1 for LIBs. [12,16] Besides, the confined interlayer spacing (3.5 Å) in graphitic carbon is unfavorable for fast K + intercalation/ deintercalation, and severe volume change will occur when accommodating more K + , leading to poor rate, low capacity, and inferior cycling stability. [17] Different from graphite, hard carbon Pore-structure design with increased ion-diffusion ability is usually regarded as an effective strategy to improve K-storage performance in hard carbon (HC). However, the relationship between porous structure and K + migration behavior remains unclear and requires further exploration. Herein, a series of chemically activated hard carbon spheres (denoted as AHCSs) with controllable micro/ mesopores structure are successfully synthesized to explore intercorrelation between micro/mesopores and K migration behavior. The experimental results indicate AHCSs have two different K + storage ways, that is, adsorption behavior at high potential region and intercalation process at low potential region. These behaviors are closely related to the pores structure evolution: the micropores afford extra active sites for efficient K-ions adsorption, and therefore positive correlation between micropores and adsorption-contributed capacity is confirmed; the mesopores permit more K-ions intercalation/deintercalation by offering adequate pathways, and as a result positive correlations between mesopores and intercalation-contributed capacity as well as initial Coulombic efficiency are revealed. All these together contribute to achieving excellent reversible capacity, and exceptional rate capability with an ultra-long cycle lifespan in PIBs, and simultaneously exhibit a high energy density as well as considerable cycling stability for potassium-ion full cells. These results promote a fundamental understanding of K + migration beha...