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The high rate performance of a battery requires the anode to be conductive not just ionically but also electronically. This criterion has significantly stimulated the study on 3D porous topological metals composed of nonmetal atoms with a light mass. Many carbon-based 3D topological metals for batteries have been reported, while similar work for 3D boron remains missing. Here, we report the first study of a 3D boron topological metal as an anode material for Li or Na ions. Based on systematic calculations, we found that the reported 3D topological metal H-boron composed of B4 cluster shows a low mass density (0.91 g/cm3) with multiple adsorption sites for Li and Na ions due to the electron-deficient feature of boron, leading to an ultrahigh specific capacity of 930 mAh/g for Li and Na ions with a small migration barrier of 0.15 and 0.22 eV, respectively, and small volume changes of 0.6% and 9.8%. These intriguing features demonstrate that B-based 3D topological quantum porous materials are worthy of further study for batteries.

All-solid-state sodium-ion batteries (ASIBs) are promising candidates for large-scale energy storage applications. To build such a battery system, efficient solid-state electrolytes (SSEs) with high sodium ionic conductivity at room temperature and good electrochemical stability as well as interface compatibility are required. In this work, using density functional theory combined with molecular dynamics simulation and a phase diagram, we have studied the potential of yttrium halide-based materials (Na

Photocatalytic reduction of hexavalent chromium (Cr (VI)) has received widespread attention due to its high toxicity, in which the interfacial electrons generation and transfer on the conduction of the semiconductor surface was the key factor. Herein, Polydopamine (PDA) as hole scavengers and eco-benign polymer, was modified on the TiO2 surface which can not only enhance the hole-electron separation and then generate more long-lived electrons for Cr (VI) reduction but also harvest visible light. Different coated thickness of TiO2/PDA has systematically been investigated for the effect on the electrons generation and reduction treatment ability of Cr (VI), the results showed that TiO2/PDA-15 exhibited the more localized electron, making it advantageous for Cr (VI) removal. The reduction kinetics of Cr (VI) by electrons exhibited two distinct phases: an initial fast reduction and then slow decay removal due to the deposition of Cr (OH)3 solids on the synthesized TiO2 surface in neutral or alkali conditions. While, in the acidic solution, fast removal of Cr (VI) was obtained only within 3 min. A wastewater treatment and a preliminary in vivo study on Daphnia magna experiment suggested that treatment with the TiO2/PDA-15 can effectively remove Cr (VI) and significantly reduce its lethality.

Motivated by the recent progress in synthesizing graphene by using aromatic benzene molecules as precursors, herein, we propose a new two-dimensional (2D) carbon allotrope by using nonaromatic molecule cyclooctatetraene as the precursor from a bottom-up approach. In this structure, all the carbon atoms are threefold coordinated, similar to the sp2-hybridized atoms in graphene; thus, we name the poly-cyclooctatetraene framework as PCF-graphene. First-principles calculations reveal that although PCF-graphene is metastable compared with graphene, it is thermally, mechanically, and dynamically stable. Different from graphene with a single-atomic thickness and zero band gap, PCF-graphene has a finite thickness of 2.45 A and is a semiconductor with a direct band gap of 0.77 eV. It exhibits anisotropies in mechanical properties, carrier mobility, and optical adsorption because of its anisotropic lattice. This study not only sheds insights into the design of 2D carbon materials from some simple organic molecules ...

It is of great importance to explore new materials beyond conventional ones for CO2 conversions. Inspired by the edge-state-enhanced conductivity in topological nodal-line semimetals (NLSs) and the...

Motivated by the feasibility of hybridizing C- and BN-units as well as the recent synthesis of a triphenylene-graphdiyne (TpG) monolayer, for the first time we explore the stability and electronic band structure of the Tp-BNyne monolayer composed of C-chains and the BN analog of triphenylene (Tp-BNyne) by using density functional theory. We find that the single layer Tp-BNyne is stable and exhibits a semiconducting character with a direct band gap of 3.78 eV. The band gap of Tp-BNyne can be flexibly tuned in a wide range by applying uniaxial straining in different directions, or by changing the length of the carbon chain, or by stacking in multilayers with different configurations, while the feature of a direct band gap can be well maintained. These intriguing characteristics endow the Tp-BNyne monolayer with additional advantages over the pristine TpG monolayer, which would stimulate more effort on the design and synthesis of novel 2D materials with high stability, tunable porosity, and controllable functionality for nanoelectronic and optoelectronic applications.

The shuttle effect caused by polysufides dissolution and diffusion in electrolyte solutions severely hinders the practical application of Li S batteries. To overcome this problem for achieving long cycle life and high rate performance, anchoring materials are highly desirable. In this work, for the first time, we explore the anchoring behaviors of polysulfides on C3B and C3N monolayers with reference to pristine graphene by using density functional theory computations. The complicated anchoring mechanisms are further explored by analyzing the competition between van der Waals, electrostatic, and chemical interactions. Our results suggest that C3B monolayer shows the best anchoring performance for lithium polysulfides due to the strong chemical interaction induced by charge transfer while C3N monolayer has relative weak anchoring effect due to the electrostatic interaction. Based on the enhanced conductivity, strong anchoring ability, and improved rate capability, C3B monolayer shows the promise as an anchoring material for lithium-sulfur batteries.

Due to the structural failure of layered CoO2, there has been considerable effort to improve the reversible capacity of commercial LiCoO2 cathode materials. Using a global structural search, we have discovered a rutile-like CoO2 phase as the ground state at 50 GPa. The material is thermally, mechanically and dynamically stable, even after removing the pressure. We show that, when lithiated, this LiCoO2 material can serve as an improved cathode material for Li-ion batteries. Its many advantages include good structural stability against transition metal migration and oxygen loss, one-dimensional channels for Li ion diffusion with variable energy barriers (0.36–0.86 eV), enhanced ionic mobility, and good intrinsic electronic conductivity brought about by its metallic band structure. Furthermore, with a voltage platform of 3.2–3.8 V, it provides better stability against conventional carbonate solvents than conventional layered cathode materials (>4.0 V). All these features demonstrate that the non-layered CoO2 phase synthesized at high pressure would be a promising cathode material, providing a performance beyond that of the currently used layered phase.

Exosomes are a type of nano-scale biofilm-enclosed vesicles involved in intercellular communications, which are actively secreted by almost all eukaryotes and have been suggested to play an important role in various biological and physiological processes. Since exosomes carry biological contents informative of the original cells and can be easily harvested from body fluids, they are regarded as an emerging and promising biomarker bank for liquid biopsy. Conventional exosome detection methods such as transmission electron microscopy, nanoparticle tracking analysis, and Western blotting are cumbersomely conducted with partial information and limited in sensitivity and specificity. Thus new analytical approaches are urgently needed to facilitate exosome-based in vitro early diagnosis of diseases. Herein, we summarized recent advances in the development of immunoassay-based technologies for rapid exosome detection which have sparked huge interest in the last few years. A brief introduction of exosomes and general principles of immunoassays was first presented. We then described in some detail the studies on four major types of immunoassay technologies incorporated with specific configurations for exosome quantification as well as surface protein profiling, including single immunosensors, immunosensor arrays, immunoassays integrated with microfluidics, and paper-based immunoassays. Challenges and future research perspectives were also discussed in the field of exosome immunoassay detection.

Halide materials are of current interest for all-solid-state batteries. In this study, we systematically studied seven fluorides Li 3MF6 (M = Al, Sc, Ti, V, Cr, Ga, In) using density functional theory combined with molecular dynamics simulation and the grand potential phase diagram analysis. Among them, Li3ScF6 is identified to be a promising solid electrolyte for lithium ion batteries with high Li ionic conductivity of 0.28 mS/cm at room temperature, wide electrochemical window of 0.59–6.38 V, and excellent interfacial stability with high-voltage cathodes including LiMn 1.5Ni0.5O4 (4.7 V), LiCoPO4 (4.8 V), and LiNiPO4 (5.1 V). Besides, Li3AlF6 is identified as a potential coating material with high-anodic limit of 6.48 V and good compatibility with cathodes and sulfide-based solid electrolytes. This study expands the family of halide materials for battery applications.

It has been a great challenge to develop a high-rate anode material with high-capacity, fast Li-ions diffusion and long cycling life going beyond the commercially used graphite in Li-ion battery. Here for the first time we propose a strategy combined high-pressure synthesis method with the global structure search to find a topological semimetal porous carbon as the desired anode. Our crystal-structure searching shows that we can obtain the ground state of an orthorhombic phase $\mathrm{Li}{\mathrm{C}}_{6}$ with regular pores at 30 GPa, and when the Li atoms are removed, the resulting carbon structure is the recently predicted interlocked graphene network (IGN) that is a topological semimetal with an intrinsic high electronic conductivity. Based on the state-of-the-art first-principles calculations, we further find that the Li-ion migration energy barrier in the IGN is extremely low and the estimated diffusion coefficient can reach a magnitude of ${10}^{\ensuremath{-}4}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}/\mathrm{s}$ at both low and high Li concentrations, which is three orders of magnitude larger than that of graphite anode. Moreover, the volume changes during the Li insertion and deinsertion are smaller than $3.2%$, while the theoretical specific capacity is the same as that of graphite anode. Our studies not only suggest a practical way of synthesizing the topological semimetal carbon but also propose a new anode material for Li-ion battery.

Extensive efforts have been devoted to C-Si compound materials for improving the limited specific capacity of graphite anode and avoiding the huge volume change of Si anode in Li-ion battery, but not much progress has been made during the past decades. Here, for the first time we apply the targeted structure search by using Li in desired quantity as chemical template to regulate the bonding between C and Si, which makes searching more feasible for us to find a new stable phase of C2Si (labelled as T-C2Si) that can better fit the XRD data of silicon dicarbide synthesized before. Different from the conventional semiconducting silicon carbides, T-C2Si is not only metallic with high intrinsic conductivity for electrons transport, but also porous with regularly distributed channels in suitable size for Li ions experiencing a low energy barrier. T-C2Si exhibits a high specific capacity of 515 mA/g, a high average open-circuit voltage of 1.14 eV, and a low volume change of 1.6%. These parameters meet the requirements of an ideal anode material with high performance for electric vehicles. Moreover, our targeted search strategy guarantees the resulting anode material with a desirable specific capacity and a small volume change during charging /discharging, and it can be used to find new geometric configurations for other materials., Comment: Submitted to Journal of Materials Chemistry A at 27-Mar-2018, Manuscript ID is: TA-ART-03-2018-002807

Three metallic three-dimensional (3D) microporous SiC4 crystals are identified for the first time by using an unbiased structure search based on the particle-swarm optimization (PSO) algorithm combined with density functional theory (DFT) calculations, which are found to be thermally, dynamically and mechanically stable. The unusual metallicity of these three microporous SiC4 allotropes stems from the delocalized p electrons along carbon ribbons or chains. Moreover, empowered by the appropriate channel size and metallic feature, SiC4-Ⅰ manifests as a promising anode material for Na-ion batteries with theoretical capacity of 176.3 mAhg−1, diffusion energy barrier of 0.25–0.41 eV for Na ions, appropriate average open circuit voltage of 0.55 V and negligible volume change of 0.57% during charging/discharging process.