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Constructing 3D skeletons modified with lithiophilic seeds has proven effective in achieving dendrite-free lithium metal anodes. However, these lithiophilic seeds are mostly alloy- or conversion-type materials, and they tend to aggregate and redistribute during cycling, resulting in the failure of regulating Li deposition. Herein, we address this crucial but long-neglected issue by using intercalation-type lithiophilic seeds, which enable antiaggregation owing to their negligible volume expansion and high electrochemical stability against Li. To exemplify this, a 3D carbon-based host is built, in which ultrafine TiO

Semiconductors with broadband photoelectric response have important practical needs in many aspects such as solar energy conversion, photocatalysis, and photodetection. We synthesized the first photochromic semiconductive hydrogen-bonded organic framework (HOF), [H

The non-uniform aggregation of fast-diffused Li on an anode surface would aggravate its tip-effect-induced nucleation/growth, leading to the notorious dendrite growth in Li metal batteries (LMBs). Tuning the Li diffusion on the anode surface has been regarded previously as a mainstream method to induce its uniform deposition, while the diffusion of Li in the anode bulk is usually ignored. Here, conceptually different from the classic surface modification, we propose a molecular tunnelling strategy to construct atomic channels in graphite bulk, which enables the fast diffusion of superdense Li. Density functional theory calculations and ab initio molecular dynamics simulations prove that the bulk diffusion through atomic channels could become a new and dominating path. Its reversible and efficient diffusion has been further visualized by in situ transmission electron microscopy. As a result, when coupled with high-loading LiFePO4 cathodes (20 mg cm−2), a high areal capacity and 100% capacity retention are achieved over 370 cycles. Through this work a new strategy is developed based on the bulk-diffusion of superdense Li for dendrite-free LMBs, which can be pervasive in other high-performance energy storage systems.

A new insight into the pressure-induced transition in graphite has been presented based on the DAC technique with hydrostatic pressure by compressing the well-crystallized HOPG.

We found two Zn(ii) compounds with similar metalloviologen structures that, upon being exposed to light at room temperature in air, generated Zn(i) species.

Low fertility rates and an aging society, growing long-term care needs, and workforce shortages in professional, industrial, and care sectors are emerging issues in South Korea and Taiwan. Both governments have pursued economic/industrial growth as productive welfare capitalism and enacted preferred selective migration policies to recruit white-collar migrant workers (MWs) as mobile elites, but they have also adopted regulations and limitations on blue-collar MWs through unfree labor relations, precarious employment, and temporary legal status to provide supplemental labor. In order to demonstrate how multiple policy regulations from a national level affect MWs’ precarity of labor in their receiving countries, which in turn affect MWs’ im/mobilities, this article presents the growing trends of transnational MWs, regardless of them being high- or low-skilled MWs, and it evaluates four dimensions of labor migration policies—MWs’ working and employment conditions, social protection, union rights and political participation, and access to permanent residency in both countries. We found that the rights and working conditions of low-skilled MWs in Korea and Taiwan are improving slowly, but still lag behind those of high-skilled MWs which also affects their public health and well-being. The significant difference identified here is that MWs in Taiwan can organize labor unions, which is strictly prohibited in Korea; pension protection also differs between the nations. Additionally, an application for permanent residency is easier for high-skilled migrant workers compared with low-skilled MWs and both the Korean and Taiwanese immigration policies differentiate the entry and resident status for low-skilled and professional MWs from dissimilar class backgrounds. Policy recommendations for both countries are also discussed.

Owing to the dramatically enhanced charge-mass transport and abundant electrochemically active sites, transition metal compound electrodes are increasingly attractive for achieving high-performance supercapacitors (SCs). Here, we report the fabrication of nickel foam supported three-dimensional (3D) branched nickel–cobalt phosphides@tri-metal cobalt–nickel-molybdenum phosphides core/shell nanowire heterostructures (denoted as NiCo-P@CoNiMo-P) as high-performance electrode materials for hybrid supercapacitors. The presence of multiple valences of the cations in such NiCo-P@CoNiMo-P enables rich redox reactions and promoted synergy effects. Benefiting from their collective effects, the resulting electrode demonstrates high specific capacity of 1366 C g−1 at 2 A g−1 (2.03 C cm−2 at 2 mA cm−2) and 922 C g−1 at 10 A g−1, as well as good cycling stability (retaining ~ 94% of the initial capacity after 6000 cycles at 15 A g−1). A hybrid SC using the NiCo-P@CoNiMo-P as the positive electrode and N-doped rGOs as the negative electrode exhibits a high energy density of 81.4 Wh kg−1 at a power density of 1213 W kg−1 and a capacity retention of 132% even after 6000 cycles at 10 A g−1. Our findings can facilitate the material design for boosting the performance of transition metal compounds based materials for fast energy storage.

Two-dimensional layered materials commonly face hindered electron transfer and poor structure stability, thus limiting their application in high-rate and long-term sodium ion batteries. In the current study, we adopt finite element simulation to guide the rational design of nanostructures. By calculating the von Mises stress distribution of a series of carbon materials, we find that the hollow biconcave structure could effectively alleviate the stress concentration resulting from expansion. Accordingly, we propose a biconcave-alleviated strategy based on the Aspergillus niger-derived carbon (ANDC) to construct ANDC/MoS2 with a hollow biconcave structure. The ANDC/MoS2 is endowed with an excellent long-term cyclability as an anode of sodium ion batteries, delivering a discharge capacity of 496 mAh g-1 after 1000 cycles at 1 A g-1. A capacity retention rate of 94.5% is achieved, an increase of almost seven times compared with the bare MoS2 nanosheets. Even at a high current density of 5 A g-1, a reversible discharge capacity around 400 mAh g-1 is maintained after 300 cycles. ANDC/MoS2 could also be used for efficient lithium storage. By using in situ TEM, we further reveal that the hollow biconcave structure of ANDC/MoS2 has enabled stable and fast sodiation/desodiation.

Similarities in sizes, shapes, and physical properties between carbon dioxide (CO 2 ) and acetylene (C 2 H 2 ) make it a great challenge to separate the major impurity CO 2 from products in C 2 H 2 production. The use of porous materials is an appealing path to replace current very costly and energy-consuming technologies, such as solvent extraction and cryogenic distillation; however, high CO 2 /C 2 H 2 uptake ratio with minor adsorption of C 2 H 2 at standard pressure was only unexpectedly observed in scarce examples in recent years although the related research started early at 1950s, and general design strategies to realize this aim are still absent. This work has successfully developed an efficient PIET strategy and obtained the second highest CO 2 /C 2 H 2 adsorption ratio for porous materials in a proof-of-concept MOF with a photochromism-active bipyridinium zwitterion. An unprecedented photocontrollable gate effect, owing to change of interannular dihedral after photoinduced generation of radical species, was also observed for the first time. These findings will inspire design and synthesis of porous materials for high efficient gas adsorption and separation.

A high contrast of ∼67 times, exceeding those of all known photoswitching bulk quadratic nonlinear-optical materials, has been realized in a photochromic semiconductor, by the strategy of increasing electron-transfer efficiency and self-absorption.

Photoresponse ranges of commercially prevailing photoelectric semiconductors, typically Si and InGaAs, are far from fully covering the whole solar spectrum (∼295-2500 nm), resulting in insufficient solar energy conversion or narrow wave bands for photoelectric detection. Recent studies have shown that infinite π-aggregation of viologen radicals can provide semiconductors with a photoelectric response range covering the solar spectrum. However, controlled assembly of an infinite π-aggregate is still a great challenge in material design. Through directional self-assembly of electron-transfer photoactive polycyclic ligands, two crystalline inorganic-organic hybrid photochromic viologen-based bismuth halide semiconductors, ((Me)3pytpy)[BiCl6]·2H2O [1; (Me)3pytpy = N,N',N″-trimethyl-2,4,6-tris(4-pyridyl)pyridine] and ((Me)3pytpy)[Bi2Cl9]·H2O (2), have been synthesized. They represent the first series of pytpy-based photochromic compounds. After photoinduced coloration, the conductivities of both 1 and 2 increased. The radical products have electron absorption bands in the range of 200-1600 nm, exceeding that of Si. Both the conductivity and the photocurrent intensity of 2 are stronger than those of 1, due to better planarity, tighter π-stacking, and higher degrees of overlap of ((Me)3pytpy)3+ cations. This study not only provides a new design idea for synthesizing radical-based multispectral photoelectric semiconductors but also enriches the family of electron-transfer photochromic compounds.

Charge-separated states with a lifetime scale of seconds or longer not only favor studies using various steady-state analysis techniques but are important for light-energy conversion and other applications. Through a steric-hindrance-induced method, unprecedented photoinduced generation of a partially charge separated (PCS) state with a lifetime of days has been detected in the "visual" mode during the decay of excited states to a commonly observed fully charge separated (FCS) state for viologen analogues. One pale yellow 4,4'-bipyridine-based metalloviologen compound, with an interannular dihedral angle of 1.84° in 4,4'-bipyridine, directly decays to the purple FCS state after photoexcitation. The other pale yellow compound, with a similar coordination framework but a larger interannular dihedral angle (33.74°), changes first to a yellow PCS state and then relaxes slowly (in the dark in Ar, ca. 2 days; 70 °C in Ar, ca. 1 h) to the purple FCS state. The two-step coloration phenomenon is unprecedented for viologen compounds and their analogues and also rather rare for other photochromic species. EPR and Raman data reveal that photoinduced charge separation first generates univalent zinc and radicals and then the received electron in Zn(I) slowly distributes further to 4,4'-bipyridine. Reduction of π-conjugation and a direct to indirect change in band gap account for the prolongation of the relaxation process and the capture of the PCS state. These findings help to understand and control decay processes of excited states and provide a potential design strategy for multicolor photochromism, light-energy conversion with high efficiency, or other applications.

By increasing contact between pre-existing paramagnetic centers and photoinduced radicals, a photochromic single-molecule magnet with large magnetization change (+20.9%) at room temperature and paramagnetic to ferromagnetic transition was successfully achieved. The increasing amplitude of magnetization was the largest among the radical-based photomagnetic systems.