Songshan Lake Materials Laboratory

Y Artificial intelligence (AI) coupled with promising machine learning (ML) techniques well known from computer science is broadly affecting many aspects of various fields including science and technology, industry, and even our day-to-day life. The ML techniques have been developed to analyze high-throughput data with a view to obtaining useful insights, categorizing, predicting, and making evidence-based decisions in novel ways, which will promote the growth of novel applications and fuel the sustainable booming of AI. This paper undertakes a comprehensive survey on the development and application of AI in different aspects of fundamental sciences, including information science, mathematics, medical science, materials science, geoscience, life science, physics, and chemistry. The challenges that each discipline of science meets, and the potentials of AI techniques to handle these challenges, are discussed in detail. Moreover, we shed light on new research trends entailing the integration of AI into each scientific discipline. The aim of this paper is to provide a broad research guideline on fundamental sciences with potential infusion of AI, to help motivate researchers to deeply understand the state-of-the-art applications of AI-based fundamental sciences, and thereby to help promote the continuous development of these fundamental sciences.

Aqueous Zn batteries that provide a synergistic integration of absolute safety and high energy density have been considered as highly promising energy-storage systems for powering electronics. Despite the rapid progress made in developing high-performance cathodes and electrolytes, the underestimated but non-negligible dendrites of Zn anode have been observed to shorten battery lifespan. Herein, this dendrite issue in Zn anodes, with regard to fundamentals, protection strategies, characterization techniques, and theoretical simulations, is systematically discussed. An overall comparison between the Zn dendrite and its Li and Al counterparts, to highlight their differences in both origin and topology, is given. Subsequently, in-depth clarifications of the specific influence factors of Zn dendrites, including the accumulation effect and the cathode loading mass (a distinct factor for laboratory studies and practical applications) are presented. Recent advances in Zn dendrite protection are then comprehensively summarized and categorized to generate an overview of respective superiorities and limitations of various strategies. Accordingly, theoretical computations and advanced characterization approaches are introduced as mechanism guidelines and measurement criteria for dendrite suppression, respectively. The concluding section emphasizes future challenges in addressing the Zn dendrite issue and potential approaches to further promoting the lifespan of Zn batteries.

Defect engineering is widely applied in transition metal dichalcogenides (TMDs) to achieve electrical, optical, magnetic, and catalytic regulation. Vacancies, regarded as a type of extremely delicate defect, are acknowledged to be effective and flexible in general catalytic modulation. However, the influence of vacancy states in addition to concentration on catalysis still remains vague. Thus, via high throughput calculations, the optimized sulfur vacancy (S-vacancy) state in terms of both concentration and distribution is initially figured out among a series of MoS2 models for the hydrogen evolution reaction (HER). In order to realize it, a facile and mild H2O2 chemical etching strategy is implemented to introduce homogeneously distributed single S-vacancies onto the MoS2 nanosheet surface. By systematic tuning of the etching duration, etching temperature, and etching solution concentration, comprehensive modulation of the S-vacancy state is achieved. The optimal HER performance reaches a Tafel slope of 48 mV dec–1 and an overpotential of 131 mV at a current density of 10 mA cm–2, indicating the superiority of single S-vacancies over agglomerate S-vacancies. This is ascribed to the more effective surface electronic structure engineering as well as the boosted electrical transport properties. By bridging the gap, to some extent, between precise design from theory and practical modulation in experiments, the proposed strategy extends defect engineering to a more sophisticated level to further unlock the potential of catalytic performance enhancement.

We establish exact relations between the winding of "energy" (eigenvalue of Hamiltonian) on the complex plane as momentum traverses the Brillouin zone with periodic boundary condition, and the presence of "skin modes" with open boundary conditions in non-Hermitian systems. We show that the nonzero winding with respect to any complex reference energy leads to the presence of skin modes, and vice versa. We also show that both the nonzero winding and the presence of skin modes share the common physical origin that is the nonvanishing current through the system.

Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.

There is interest in metal single atom catalysts due to their remarkable activity and stability. However, the synthesis of metal single atom catalysts remains somewhat ad hoc, with no universal strategy yet reported that allows their generic synthesis. Herein, we report a universal synthetic strategy that allows the synthesis of transition metal single atom catalysts containing Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Pt or combinations thereof. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and extended X-ray absorption fine structure spectroscopy confirm that the transition metal atoms are uniformly dispersed over a carbon black support. The introduced synthetic method allows the production of carbon-supported metal single atom catalysts in large quantities (>1 kg scale) with high metal loadings. A Ni single atom catalyst exhibits outstanding activity for electrochemical reduction of carbon dioxide to carbon monoxide, achieving a 98.9% Faradaic efficiency at -1.2 V.

Abstract Developing highly active and durable electrocatalysts for acidic oxygen evolution reaction remains a great challenge due to the sluggish kinetics of the four-electron transfer reaction and severe catalyst dissolution. Here we report an electrochemical lithium intercalation method to improve both the activity and stability of RuO 2 for acidic oxygen evolution reaction. The lithium intercalates into the lattice interstices of RuO 2 , donates electrons and distorts the local structure. Therefore, the Ru valence state is lowered with formation of stable Li-O-Ru local structure, and the Ru–O covalency is weakened, which suppresses the dissolution of Ru, resulting in greatly enhanced durability. Meanwhile, the inherent lattice strain results in the surface structural distortion of Li x RuO 2 and activates the dangling O atom near the Ru active site as a proton acceptor, which stabilizes the OOH* and dramatically enhances the activity. This work provides an effective strategy to develop highly efficient catalyst towards water splitting.

We provide a systematic and self-consistent method to calculate the generalized Brillouin zone (GBZ) analytically in one-dimensional non-Hermitian systems, which helps us to understand the non-Hermitian bulk-boundary correspondence. In general, a n-band non-Hermitian Hamiltonian is constituted by n distinct sub-GBZs, each of which is a piecewise analytic closed loop. Based on the concept of resultant, we can show that all the analytic properties of the GBZ can be characterized by an algebraic equation, the solution of which in the complex plane is dubbed as auxiliary GBZ (aGBZ). We also provide a systematic method to obtain the GBZ from aGBZ. Two physical applications are also discussed. Our method provides an analytic approach to the spectral problem of open boundary non-Hermitian systems in the thermodynamic limit.

Abstract Hydrogel electrolytes have attracted increasing attention due to their potential uses in the fabrication of flexible solid‐state batteries. However, the development of hydrogel electrolytes is still in the initial stage and the number of available strategies is limited. Ideally, the hydrogel electrolyte should exhibit suitable ionic conductivity rate, mechanical strength, and biocompatibility for safety. In this study, a zwitterionic sulfobetaine/cellulose hydrogel electrolyte is fabricated using raw materials from natural plants, which exhibits a good biocompatibility with mammalian cells. The intrinsic zwitterionic groups on sulfobetaine chains can provide separated ion migration channels for positive and negative ions, which largely facilitates electrolyte ion transport. A solid‐state Zn‐MnO 2 battery with a fabricated zwitterionic gel electrolyte exhibits a very high rate performance. It exhibits a specific capacity of 275 mA h at 1 C. Even up to 30 C, a high capacity of 74 mA h is maintained during the charging–discharging for up to 10 000 cycles. For wearable applications, the flexible solid‐state batteries can be used as reliable and portable sources to power different wearable electronics such as a commercial smart watch, electroluminescent panel, and color electroluminescence line, which shows their large potentials for use in next‐generation flexible and wearable battery technologies.

Abstract Rechargeable aqueous zinc ion batteries (AZIBs), as a rising star in aqueous ion batteries, are restricted by the narrow voltage window and the unsatisfactory reversibility, which are dominated by the high activity of H 2 O molecules, side reaction, Zn dendrites, and structural degeneration of the cathode. Electrolyte manipulation has seen a great deal of research recently, particularly various kinds of organic molecules have been shown to achieve outstanding effects on stabilizing the Zn anode, yet the exploration of the mechanism behind the high performance has not been thorough. In an attempt to find such underlying principles, the basic reactions and the corresponding progress on the anode side of AZIBs are first assessed. Then, the roles of organic molecules in recent studies are researched, followed by a deep insight into the role of organic molecules. Finally, several designed strategies are proposed for the further exploration of high performance aqueous rechargeable ZIBs through incorporating appropriate organic molecules in the electrolytes.

Abstract Li-ion-conducting chloride solid electrolytes receive considerable attention due to their physicochemical characteristics such as high ionic conductivity, deformability and oxidative stability. However, the raw materials are expensive, and large-scale use of this class of inorganic superionic conductors seems unlikely. Here, a cost-effective chloride solid electrolyte, Li 2 ZrCl 6 , is reported. Its raw materials are several orders of magnitude cheaper than those for the state-of-the-art chloride solid electrolytes, but high ionic conductivity (0.81 mS cm –1 at room temperature), deformability, and compatibility with 4V-class cathodes are still simultaneously achieved in Li 2 ZrCl 6 . Moreover, Li 2 ZrCl 6 demonstrates a humidity tolerance with no sign of moisture uptake or conductivity degradation after exposure to an atmosphere with 5% relative humidity. By combining Li 2 ZrCl 6 with the Li-In anode and the single-crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode, we report a room-temperature all-solid-state cell with a stable specific capacity of about 150 mAh g –1 for 200 cycles at 200 mA g –1 .

Abstract The photocatalytic CO 2 reduction reaction (CRR) holds great promise for curbing anthropogenic CO 2 emissions, though boosting photocatalyst activity and tuning product selectivity remain key priorities. Herein, isolated Ni single atoms dispersed on defect rich zirconia (Ni‐SA‐ x /ZrO 2 ) are identified as a very promising photocatalyst for CRR under Xe lamp irradiation, showing good activity and CO selectivity in the absence of added sacrificial agents or sensitizers. Due to an abundance of accessible nickel single atomic sites, the optimized photocatalyst affords CO at a rate of 11.8 µmol g −1 h −1 (92.5% selectivity). Experimental and theoretical investigations determine that the atomically dispersed Ni sites lower the energy barrier for CO 2 to CO conversion via an adsorbed COOH intermediate, while also suppressing H 2 desorption in the competing water splitting reaction. The Ni single atom sites thus simultaneously promote CO 2 conversion and CO selectivity, thus offering valuable new insights for the future design of improved metal single‐atom catalysts for CRR.

Skin effect, experimentally discovered in one dimension, describes the physical phenomenon that on an open chain, an extensive number of eigenstates of a non-Hermitian Hamiltonian are localized at the end(s) of the chain. Here in two and higher dimensions, we establish a theorem that the skin effect exists, if and only if periodic-boundary spectrum of the Hamiltonian covers a finite area on the complex plane. This theorem establishes the universality of the effect, because the above condition is satisfied in almost every generic non-Hermitian Hamiltonian, and, unlike in one dimension, is compatible with all point-group symmetries. We propose two new types of skin effect in two and higher dimensions: the corner-skin effect where all eigenstates are localized at corners of the system, and the geometry-dependent-skin effect where skin modes disappear for systems of a particular shape, but appear on generic polygons. An immediate corollary of our theorem is that any non-Hermitian system having exceptional points (lines) in two (three) dimensions exhibits skin effect, making this phenomenon accessible to experiments in photonic crystals, Weyl semimetals, and Kondo insulators.

This review provides an up-to-date summary of the progress of organic quinones as electroactive materials for advanced electrochemical energy storage devices.

Abstract Carbon‐supported Ni II single‐atom catalysts with a tetradentate Ni‐N 2 O 2 coordination formed by a Schiff base ligand‐mediated pyrolysis strategy are presented. A Ni II complex of the Schiff base ligand ( R , R )‐(−)‐N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐cyclohexanediamine was adsorbed onto a carbon black support, followed by pyrolysis of the modified carbon material at 300 °C in Ar. The Ni‐N 2 O 2 /C catalyst showed excellent performance for the electrocatalytic reduction of O 2 to H 2 O 2 through a two‐electron transfer process in alkaline conditions, with a H 2 O 2 selectivity of 96 %. At a current density of 70 mA cm −2 , a H 2 O 2 production rate of 5.9 mol g cat. −1 h −1 was achieved using a three‐phase flow cell, with good catalyst stability maintained over 8 h of testing. The Ni‐N 2 O 2 /C catalyst could electrocatalytically reduce O 2 in air to H 2 O 2 at a high current density, still affording a high H 2 O 2 selectivity (>90 %). A precise Ni‐N 2 O 2 coordination was key to the performance.

Abstract The discovery of ferromagnetic two-dimensional van der Waals materials has opened up opportunities to explore intriguing physics and to develop innovative spintronic devices. However, controllable synthesis of these 2D ferromagnets and enhancing their stability under ambient conditions remain challenging. Here, we report chemical vapor deposition growth of air-stable 2D metallic 1T-CrTe 2 ultrathin crystals with controlled thickness. Their long-range ferromagnetic ordering is confirmed by a robust anomalous Hall effect, which has seldom been observed in other layered 2D materials grown by chemical vapor deposition. With reducing the thickness of 1T-CrTe 2 from tens of nanometers to several nanometers, the easy axis changes from in-plane to out-of-plane. Monotonic increase of Curie temperature with the thickness decreasing from ~130.0 to ~7.6 nm is observed. Theoretical calculations indicate that the weakening of the Coulomb screening in the two-dimensional limit plays a crucial role in the change of magnetic properties.

As a promising anode for aqueous batteries, Zn metal shows a number of attractive advantages such as low cost, low redox potential, high capacity, and environmental benignity. Nevertheless, the quick growth of dendrites/protrusions on the “hostless” Zn anodes not only enlarges batteries’ internal resistance but also causes sudden shorting failure by piercing separators. Herein, we report a novel heterogeneous seed method to guide the morphology evolution of plated Zn. The heterogeneous seeds are sputtering-deposited quasi-isolated nano-Au particles (Au-NPs) that enable a uniform and stable Zn-plating/stripping process on the anodes. Tested on Zn|Zn symmetric cells, the Au-nanoparticle (NP) decorated Zn anodes (NA-Zn) demonstrate much better cycling stability than the bare ones (92 vs 2000 h). In NA-Zn|CNT/MnO2 batteries, this heterogeneous seed prolongs the lifetime of the device from ∼480 cycles up to 2000 cycles. This work offers a facile and promising Zn dendrite/protrusion suppressing route for the achievement of long-life Zn-ion batteries.

can be effectively switched by the spin-orbit torques (SOTs) originated from the current flowing in the Pt layer. The effective magnetic fields corresponding to the SOTs are further quantitatively characterized using harmonic measurements. Our demonstration of the SOT-driven magnetization switching in a 2D vdW magnet could pave the way for implementing low-dimensional materials in the next-generation spintronic applications.

Abstract Construction of well‐defined metal–organic framework precursor is vital to derive highly efficient transition metal–carbon‐based electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. Herein, a novel strategy involving an in situ transformation of ultrathin cobalt layered double hydroxide into 2D cobalt zeolitic imidazolate framework (ZIF‐67) nanosheets grafted with 3D ZIF‐67 polyhedra supported on the surface of carbon cloth (2D/3D ZIF‐67@CC) precursor is proposed. After a low‐temperature pyrolysis, this precursor can be further converted into hybrid composites composed of ultrafine cobalt nanoparticles embedded within 2D N‐doped carbon nanosheets and 3D N‐doped hollow carbon polyhedra (Co@N‐CS/N‐HCP@CC). Experimental and density functional theory calculations results indicate that such composites have the advantages of a large number of accessible active sites, accelerated charge/mass transfer ability, the synergistic effect of components as well as an optimal water adsorption energy change. As a result, the obtained Co@N‐CS/N‐HCP@CC catalyst requires overpotentials of only 66 and 248 mV to reach a current density of 10 mA cm −2 for HER and OER in 1.0 m KOH, respectively. Remarkably, it enables an alkali‐electrolyzer with a current density of 10 mA cm −2 at a low cell voltage of 1.545 V, superior to that of the IrO 2 @CC||Pt/C@CC couple (1.592 V).

Based on first-principles calculations and symmetry analysis, we propose that EuIn_{2}As_{2} is a long-awaited axion insulator with antiferromagnetic (AFM) long-range order. Characterized by the parity-based invariant Z_{4}=2, the topological magnetoelectric effect is quantized with θ=π in the bulk, with a band gap as large as 0.1 eV. When the staggered magnetic moments of the AFM phase are along the a or b axis, it is also a topological crystalline insulator phase with gapless surface states emerging on (100), (010), and (001) surfaces. When the magnetic moments are along the c axis, both the (100) and (001) surfaces are gapped, and the material can also be viewed as a high-order topological insulator with one-dimensional chiral states existing on the hinges between those gapped surfaces. We have calculated both the topological surface states and the hinge state in different phases of the system, respectively, which can be detected by angle-resolved photoemission spectroscopy or STM experiments.