We demonstrate that biaxially strained Bi2O2Se holds unusual quadruple-well dipole orders, a two-step 90° ferroelectric switching and various types of spontaneous topological domain structures.

In this paper, we systematically explore several key properties of electronic states in one-dimensional (1D) helical crystals, including the inheritance of orbital angular momentum from local atomic orbitals to the entire helical structure, the helical momentum, and the emergence of helical -induced spin -orbit coupling (hSOC). We then apply this comprehensive theoretical framework to elucidate the electronic structure of the 1D helical crystal InSeI. Our analysis reveals the influence of hSOC, evident in spin -mixing energy gaps within the electronic band structure, as calculated through density functional theory. Utilizing a combination of tight -binding modeling and first -principles calculations, we ascertain the spin -polarized electric response and the chiral-switchable second -order photocurrent response of InSeI, characterized as the Landauer-Buttiker ballistic transport and shift current response, respectively. The results highlight the potential of 1D InSeI for applications in spintronics and optoelectronics. The overarching theoretical framework established in this work will prove invaluable for the investigation of other helical electronic systems.

Smart memristors with innovative properties are crucial for the advancement of next-generation information storage and bioinspired neuromorphic computing. However, the presence of significant sneak currents in large-scale memristor arrays results in operational errors and heat accumulation, hindering their practical utility. This study successfully synthesizes a quasi-free-standing Bi2O2Se single-crystalline film and achieves layer-controlled oxidation by developing large-scale UV-assisted intercalative oxidation, resulting β-Bi2SeO5/Bi2O2Se heterostructures. The resulting β-Bi2SeO5/Bi2O2Se memristor demonstrates remarkable self-rectifying resistive switching performance (over 105 for ON/OFF and rectification ratios, as well as nonlinearity) in both nanoscale (through conductive atomic force microscopy) and microscale (through memristor array) regimes. Furthermore, the potential for scalable production of self-rectifying β-Bi2SeO5/Bi2O2Se memristor, achieving sub-pA sneak currents to minimize cross-talk effects in high-density memristor arrays is demonstrated. The memristors also exhibit ultrafast resistive switching (sub-100 ns) and low power consumption (1.2 pJ) as characterized by pulse-mode testing. The findings suggest a synergetic effect of interfacial Schottky barriers and oxygen vacancy migration as the self-rectifying switching mechanism, elucidated through controllable β-Bi2SeO5 thickness modulation and theoretical ab initio calculations.

The quasiparticle method, which has achieved a great success in solid state electronics and crystal lattice vibration, is adopted to study the solid state ion transport. A general recipe is put forward to map the classical solid state ion system together with the short-range ion-ion repulsion to a quasiparticle quantum system based on which simple tight-binding models are set up to study popular solid state ionic issues. The derived ionic eigen-states and transport can naturally incorporate the concerted behavior. The influence of mobile ion doping to ionic conductivity is investigated by an explicit mean-field expression of ion-ion Coulomb interaction to reveal the mechanism of super-ionic conduction. Similar trick is also applied to study the the Onsager transport originated from ion-electron interference. The so called high-entropy mechanism is also explored where the lattice random distorsion and multi-site percolation exhibit positive influence to increase ionic conductivity. Our method is expected to provide a novel framework to understand and study the solid state ion transport.

Micro-sized silicon (mSi) anodes offer advantages in cost and tap density over nanosized counterparts. However, its practical application still suffers from poor cyclability and low initial and later-cycle coulombic efficiency (CE), caused by the unstable solid electrolyte interphase (SEI) and irreversible lithiation of the surface oxide layer. Herein, a bifunctional fluorine (F)-free electrolyte was designed for the mSi anode to stabilize the interphase and improve the CE. A combined analysis revealed that this electrolyte can chemically pre-lithiate the native oxide layer by the reductive LiBH4 , and relieve SEI formation and accumulation to preserve the internal conductive network. The significance of this F-free electrolyte brings unprecedented F-free interphase that also enables the high-performance mSi electrode (80 wt % mSi), including high specific capacity of 2900 mAh/g, high initial CE of 94.7 % and excellent cyclability capacity retention of 94.3 % after 100 cycles at 0.2 C. This work confirms the feasibility of F-free interphase, thus opening up a new avenue toward cost-advantaged and environmentally friendly electrolytes for more emerging battery systems.

All-solid-state alkali ion batteries represent a future trend in battery technology, as well as provide an opportunity for low-cost metal fluoride electrode materials, if certain intrinsic problems can be resolved. In this work, a liquid metal activation strategy is proposed in which liquid Ga elements are generated in situ and doped into the LiF crystal structure by introducing a small amount of GaF3 . Benefiting from these two Ga states of existence, in which the liquid metal Ga can continuously maintain conformable ion/electron-transport networks, while doped Ga in the LiF crystal structure catalyzes LiF splitting, the lithium-ion storage capacity of MnF2 significantly increases by 87%. A similar effect can be obtained in FeF3 , where the sodium-ion storage capacity is enhanced by 33%. This universal strategy with few restrictions can be used to realize a complete renaissance of metal fluorides, as well as offer an opportunity for the new application of liquid metals in the field of energy storage.

Boosting the ultralow temperature (below −30 °C) performance of Na‐ion hybrid capacitors (SIHCs), which integrate the high energy density of batteries with the high output power and long life of supercapacitors, is critical for the application of advanced electronics in extreme environments. However, their low‐temperature performance, especially fast charging capability, is hindered by difficult desolvation and slow pass solid electrolyte interphase (SEI) together with sluggish diffusion within the electrode. Herein, a “single‐solute–single‐solvent” electrolyte is developed and a through‐hole hollow carbon sphere (TH‐HCS) is constructed, and it is demonstrated through theoretical calculations and experimental investigations that the weakly solvated structure and high ionic conductivity facilitate the Na + transportation at low temperatures, the highly fluorinated SEI facilitates the Na + migration, and the through‐hole hollow structure alleviates the volume expansion during sodiation, thus ensuring fast kinetics and structural stability. As expected, TH‐HCS using this electrolyte exhibits a high specific capacity of 87.5 mAh g −1 after 11 000 cycles at 1.0 A g −1 and −40 °C. Coupled with activated carbon, the assembled SIHC displays an energy density of 106.1 and 52.0 Wh kg −1 at 25 and −40 °C, respectively, far exceeding the performance of commercial energy storage systems at low temperature.

Spin–orbit coupling in chiral materials can induce chirality-dependent spin splitting, enabling electrical manipulation of spin polarization. Here, we use first-principles calculations to investigate the electronic states of chiral one-dimensional (1D) semiconductor InSeI, which has two enantiomorphic configurations with left- and right-handedness. We find that opposite spin states exist in the left- and right-handed 1D InSeI with significant spin splitting and spin-momentum collinear locking. Although the spin states at the conduction band minimum (CBM) and valence band maximum of 1D InSeI are both nearly degenerate, a direct-to-indirect bandgap transition occurs when a moderate tensile strain (∼4%) is applied along the 1D chain direction, leading to a sizable spin splitting (∼0.11 eV) at the CBM. These findings indicate that 1D InSeI is a promising material for chiral spintronics.

Although the high-capacity Sb2S3-based anode materials for sodium-ion batteries can combine the advantages of multi-step conversion of Sb2S3 to Sb and alloying reaction between Sb and Na for improving the performance, the slow reaction kinetics, low electronic conductivity, and poor reversibility of the sodium storage process have limited their practical application. To effectively improve the electrochemical performance, a three-dimensional Sb2S3/S@S-doped carbon composite with a hollow core-shell structure based on the combination of template method and coupling reaction is successfully synthesized. By combining the finite element simulation, dynamic analysis, and density functional theory calculation, the respective roles of S-composite and hollow core-shell structure in boosting performance are revealed. The internal S and external S-doped carbon can interact with Sb2S3 to improve its reactivity with Na+, and effectively release the stress of Sb2S3 in the sodiation process. The Sdoped carbon can accelerate Na+ diffusion and further stabilize the structure of Sb2S3. Benefited from the special structure, the as-prepared anode displays high reversible capacity, superior cycle performance and high rate capability. The assembled full battery also exhibits an excellent energy density under high power, and can still maintain a high reversible capacity of 310 mAh/g at 1 A/g over 500 cycles.

Lithium dendrite (filaments) propagation in solid electrolytes (SEs) leading to short circuits is one of the biggest obstacles to the application of all-solid-state lithium metal batteries. Due to the lack of operando techniques that can provide high resolution, the insufficient knowledge of the lithium dendrite growth inside SEs makes it difficult to suppress the dendrite growth. To reveal the mechanism of the Li filament growth in SEs, we achieved real-time monitoring of the nanoscale Li filament growth by operando small-angle neutron scattering (SANS) in representative Li6.5La3Zr1.5Nb0.5O12 SEs. On continuous plating, the Li filament growth is not simply an accumulation of Li, but there is a dynamic evolution due to the competition between the Li filament growth and self-healing. With the aid of simulations and experiments, this dynamic competition was demonstrated to be highly dependent on temperature variation. The enhanced self-healing ability of Li at elevated temperatures plays a positive role in suppressing the Li filament growth. The heat therapy improved the cell's cycle life, which provided insight into suppressing the Li filament growth. Operando SANS with high Li sensitivity provides a platform for investigating Li filaments in SEs.

Recent studies in all‐solid‐state batteries (ASSBs) based on inorganic solid electrolytes (ISEs) have improved the energy density to a higher level. However, its commercialization is still delayed by many intrinsic limitations, among which the fast‐charging capability is not mentioned enough. Despite few elaborately selected electrolytes coupled with electrodes that can deliver an extremely high rate, the rate improvement strategy is still lacking. Here, a novel and effective strategy of introducing liquid metal is demonstrated to trigger the capacitive behavior in the ASSBs for the first time. Two paramount criteria of inducing capacitive behavior in ASSBs are proposed, and both of them are accomplished by utilizing liquid metal Ga. As a result, the capacitive behavior contribution to total charge storage reaches 73% at 1 mV s −1 . Benefitted from the improved kinetics, both an excellent rate of performance (81% specific capacity retained at 5 C) and a good cyclability (0.02% decay per cycle during 800 cycles at 1 C) are delivered. The universality of the liquid metal induced capacitive behavior in ASSBs is further verified in multiple active materials. This work provides a fundamental understanding of the origin of the capacitive behavior and opens a new route for fast‐charging ASSBs.

Chloride oxidation has tremendous utility in the burgeoning field of chlorine-mediated C-H activation, yet it remains a challenging process to initiate with light because of the exceedingly positive one-electron reduction potential, E° (Cl•/-), beyond most common transition-metal photooxidants. Herein, two photocatalytic chloride oxidation pathways that involve either one- or consecutive two-photon excitation of N-phenylphenothiazine (PTH) are presented. The one-photon pathway generates PTH•+ by oxidative quenching that subsequently disproportionates to yield PTH2+ that oxidizes chloride; this pathway is also accessed by the electrochemical oxidation of PTH. The two-photon pathway, which proceeded through the radical cation excited state, 2PTH•+*, was of particular interest as this super-photooxidant was capable of directly oxidizing chloride to chlorine atoms. Laser flash photolysis revealed that the photooxidation by the doublet excited state proceeded on a subnanosecond timescale through a static quenching mechanism with an ion-pairing equilibrium constant of 0.36 M-1. The PTH photoredox chemistry was quantified spectroscopically on nanosecond and longer time scales, and chloride oxidation chemistry was revealed by reactivity studies with model organic substrates. One- and two-photon excitation of PTH enabled chlorination of unactivated C(sp3)-H bonds of organic compounds such as cyclohexane with substantial yield enhancement observed from inclusion of the second excitation wavelength. This study provides new mechanistic insights into chloride oxidation catalyzed by an inexpensive and commercially available organic photooxidant.

The high interfacial resistance and lithium (Li) dendrite growth are two major challenges for solid-state Li batteries (SSLBs). The lack of understanding on the correlations between electronic conductivity and Li dendrite formation limits the success of SSLBs. Here, by diluting the electronic conductor from the interphase to bulk Li during annealing of the aluminium nitride (AlN) interlayer, we changed the interphase from mixed ionic/electronic conductive to solely ionic conductive, and from lithiophilic to lithiophobic to fundamentally understand the correlation among electronic conductivity, Li dendrite, and interfacial resistance. During the conversion-alloy reaction between AlN and Li, the lithiophilic and electronic conductive Li x Al diffused into Li, forming a compact lithiophobic and ionic conductive Li 3 N, which achieved an ultrahigh critical current density of 2.6/14.0 mA/cm 2 in the time/capacity-constant mode, respectively. The fundamental understanding on the effect of interphase nature on interfacial resistance and Li dendrite suppression will provide guidelines for designing high-performance SSLBs.

Integrating the merits of long lifespan and excellent energy as well as power densities,potassium-ion hybrid capacitors(PIHCs) exhibit great prospects for future energy storage devices.To boost comprehensive performance of PIHCs,heteroatom-doping and morphology-tuning as two comprehensive strategies have been devoted to designing uniquely structural carbon-based materials with favorable advantages.An ideal strategy for simultaneous atomic doping and structural regulation is expected to be developed.Herein,we propose a novel "Killing Two Birds with One Stone" strategy to prepare a tri-elements doped hollow carbon sphere(TED-HCS) as PIHCs anodes,that is,a single template of spherical CoP particles is rationally adopted,which not only provides both a P source for heteroatom-doping but also acts as a selfsacrificial template for hollow-structure engineering.The multifunctional TED-HCS presents a high capacity of 473.0 mAh g -1 and excellent rate performance of 212.5 mAh g -1 at 5.0 A g -1 .Remarkably,the as-assembled PIHCs show outstanding energy/power density(40.4 Wh kg -1 /10500 W kg -1 ) and remain high-capacity retention of 89.15% even cycling 12,000 times.The "Killing Two Birds with One Stone" strategy offers new insight into the search for the preparation of carbon-based materials with multi-elements doping and specific morphology structure.

Underwater acoustic wave absorption and control play an important role in underwater applications. Various types of underwater acoustic metamaterials have been proposed in recent years with the vigorous development of acoustic metamaterials. Compared with airborne sound, underwater sound waves have a longer wavelength and much smaller propagation loss, making them more difficult to control. In addition, given that the acoustic impedance of water is much greater than that of air, numerous conventional materials and structures are not suited to underwater use. In this paper, we propose a composite structure based on an excellent broadband low-frequency sound absorber of air using aluminum mixed with rubber. Our composite structure possesses broadband low-frequency (<1,000 Hz) sound absorption underwater, omnidirectional high sound absorption coefficient under the oblique incidence (0–75°), and pressure resistance. It has promising applications for underwater acoustic wave control and contributes to the design of underwater acoustic metamaterials.

The room-temperature sodium-sulfur (RT-Na/S) battery is one of the most promising technologies for low-cost energy storage. However, application of RT-Na/S batteries is currently impeded by severe shuttle effects and volume expansion that limits both energy density and cycling stability. Herein, first, the first-principal calculation is used to find that the introduction of sulfur vacancies in MoS2 can effectively enhance polysulfide adsorption and catalytic ability as well as both the ion and electron conductivities. Then, unique MoS2- x /C composite spheres are further designed and synthesized with flower-like few-layer and interlayer-enlarged MoS2- x nanosheets space-confined in hollow carbon nanospheres by a "ship-in-a-bottle" strategy. With this novel design, the mass loading of S in the MoS2- x /C composite can be reached to as high as 75 wt%. Owing to the synergetic effect of interlayer-expanded and few-layer MoS2- x nanosheets and hollow carbon spheres matrix with high electronic/Na+ conductivity, the RT-Na/S batteries deliver highly stable cycle durability (capacity retention of 85.2% after 100 cycles at 0.1 A g-1 ) and remarkable rate capability (415.7 mAh g-1 at 2 A g-1 ) along with high energy density. This design strategy of defect- and interlayer-engineering may find wide applications in synthesizing electrode materials for high-performance RT-Na/S batteries.

Potassium-ion batteries (PIBs) have been considered as potential alternatives for lithium-ion batteries since there is a demand for better anode with superior energy, excellent rate capability, and long cyclability. The high-capacity zinc selenide (ZnSe) anode, which combines the merits of conversion and alloying reactions, is promising for PIBs but suffers from poor cyclability and low electronic conductivity. To effectively boost electrochemical performance of ZnSe, a "dual-carbon-confined" structure is constructed, in which an inner N-doped microporous carbon (NMC)-coated ZnSe wrapped by outer-rGO (ZnSe@i-NMC@o-rGO) is synthesized. Combining finite element simulation, dynamic analysis, and density functional theory calculations, the respective roles of inner- and outer-carbon in boosting performance are revealed. The inner-NMC increased the reactivity of ZnSe with K+ and alleviated the volume expansion of ZnSe, while outer-rGO further stabilized the structure and promoted the reaction kinetics. Benefiting from the synergistic effect of dual-carbon, ZnSe@i-NMC@o-rGO exhibited a high specific capacity 233.4 mAh g(-1) after 1500 cycles at 2.0 A g(-1). Coupled with activated carbon, a potassium-ion hybrid capacitor displayed a high energy density of 176.6 Wh kg(-1) at 1800 W kg(-1) and a superior capacity retention of 82.51% at 2.0 A g(-1) after 11000 cycles.

Since proposed, the perforated honeycomb-corrugation sandwich panel has attracted a lot of attention due to its superior broadband sound absorption at low frequencies and excellent mechanical stiffness/strength. However, most existing studies have assumed a structure made of high-strength materials and studied its performance based on the ideal rigid-wall model with little consideration for acoustic-structure interaction, thereby neglecting the structural vibrations caused by the material's elasticity. In this paper, we developed a more realistic model considering the solid structural dynamics using the finite element method (FEM) and by applying aluminum and rubber as the structural material. The enhancement of the low-frequency performance and inhibition of broadband absorption coexisted in low-strength rubbers, implying a compromise in the selection of Young's modulus to balance these two influences. Further analysis on thermal-viscous dissipation, mechanical energy, and average structural stress indicated that the structure should work right below the resonant frequency for optimization. Based on these findings, we designed a novel aluminum-rubber composite structure possessing enhanced low-frequency absorption, high resistance to shear load, normal compression, and thermal expansion. Our research is expected to shed some light on noise control and the design of multifunctional acoustic metamaterials.