We report an effective method to enhance and modify the magnetic plasmon (MP) resonance in three-dimensional (3D) optical metamaterials consisting of periodic arrays of silver vertical split-ring ...resonators (VSRRs) for high-sensitivity sensing. By positioning the 3D metamaterials above a thick silver film separated by a silica dielectric spacer layer, the strong coupling between the MP resonance in the VSRRs and the surface plasmons polaritons (SPPs) propagating on the silver film can be realized and gives rise to an ultra-narrowband hybrid MP mode with a huge enhancement of magnetic fields. For the coupling to happen, the magnetic field direction of the SPPs should be parallel to the magnetic moment induced in the VSRRs. More importantly, because the ultra-narrowband hybrid MP mode is extremely sensitive to the surrounding media, the sensitivity and the figure of merit (FOM) of the 3D metamaterials can reach as high as 700 nm/RIU and 170, respectively, suggesting that the proposed 3D metamaterials hold potential applications in label-free biomedical sensing.
We first investigate numerically photonic microcavity-enhanced magnetic plasmon (MP) resonance in metamaterials for high-quality refractive index sensing. The metamaterials consist of a top periodic ...array of U-shaped metallic split-ring resonators (SRRs), a middle dielectric layer, and a bottom metallic backed plate. The top metallic SRRs that are placed at about Bragg distance above the bottom metallic plate constitute a photonic microcavity. Because the MP resonance excited in metallic SRRs is coupled to the photonic microcavity mode supported by the photonic microcavity, the radiative damping of the MP resonance is strongly reduced, and consequently, its linewidth is decreased dramatically. Benefiting from the narrow linewidth, large modulation depth, and giant magnetic field enhancement at the MP resonance, the cavity-coupled metamaterial sensor has very high sensitivity (S = 400 nm/RIU and S* = 26/RIU) and figure of merit (FOM = 33 and FOM* = 4215), which suggests that the proposed metamaterials have potential in applications of plasmonic biosensors.
•We investigate the diffraction coupling of magnetic resonances in metamaterials.•The diffraction coupling of magnetic resonances causes a mixed mode.•At the mixed mode, magnetic fields can be ...greatly enhanced.•The designed 3D metamaterials have high sensing performance.
We theoretically investigate the diffraction coupling of magnetic plasmon (MP) resonances in three-dimensional (3D) metamaterials comprising a rectangular array of metallic vertical split-ring resonators (VSRRs). By suspending 3D metamaterials into air to reduce the substrate effect, the interaction between MP resonances of VSRRs and a collective surface mode signaled by Wood anomaly in the periodic array can cause a narrow-band mixed mode with greatly enhanced magnetic fields. Due to the interaction, an anti-crossing phenomenon similar to Rabi splitting in atomic physics, is also observed and explained satisfactorily with the help of a coupled oscillator model. For the narrow-band mixed mode, the greatly enhanced magnetic fields in VSRR gaps are lifted off from the substrate to be fully exposed to the sensing medium. Therefore, the 3D metamaterials have good sensing performance factors (S = 900 nm/RIU, FOM = 38, and FOM* = 125), which are promising for label-free biochemical sensors.
A high-resolution (∼500 m) numerical model was used to study the reef and atoll wakes in the Xisha Archipelago (XA) during 2009. Statistical analyses of simulation data indicated strong cyclonic ...dominance in the mixing layer (above ∼35 m) and weak anticyclonic dominance in the subsurface layer (35∼160 m) for both eddies and filaments in the XA. The intrinsic dynamical properties of the flow, such as the vertical stratification and velocity magnitude, and the terrain of reefs and atolls had a significant effect on the asymmetry. Without considering the existence of reefs and atolls, the “background cyclonic dominance” generated under local planetary rotation (f≈4.1×10−5 s−1) and vertical stratification (with mean Brunt–Väisälä frequency N = 0.02 s−1 at 75 m) was stronger for filaments than eddies in the upper layer from 0∼200 m, and the larger vorticity amplitude in the cyclonic filaments could greatly enhance the cyclonic wake eddies. Furthermore, inertial–centrifugal instability induced selective destabilization of anticyclonic wake eddies in different water layers. As the Rossby number (Ro) and core vorticity (Burger number, Bu) decreased (increased) with the water depth, a more stable state was achieved for the anticyclonic wake eddies in the deeper layer. The stratification and slipping reefs and atolls also led to vertical decoupled shedding, which intensified the asymmetry.
•We report a facile method to enhance the magnetic fields of Ag nanowire pair array.•When the PBG is tuned to approach the MPPs, they interact to form a hybrid mode.•At the hybrid mode, the magnetic ...fields in Ag nanowire pairs can be greatly enhanced.•This has potential applications in magnetic nonlinearity and magnetic sensors.
We theoretically study the coupling of magnetic plasmon polaritons (MPPs) with photonic band gap (PBG) in a system composed of a one-dimensional (1D) silver nanowire pair array lying on a one-dimensional photonic crystal (1D PC). The near-field plasmon interactions in individual silver nanowire pairs induce MPPs. The 1D PC consisting of dielectric multilayer stacks with alternating refractive indices forms a PBG in the reflection spectrum. When the position of the PBG of the 1D PC is tuned to be close to the MPPs, the MPPs and the PBG can couple together to lead to a hybrid mode within the PBG. At the hybrid mode resonance, the magnetic fields in the center of Ag nanowire pairs are enhanced to nearly 4.3 times larger than those in the nanowire pair array directly lying on a substrate. Our numerical results hold important applications in magnetic sensors and magnetic nonlinearity.
Metal‐organic frameworks (MOFs) hold great promise as high‐energy anode materials for next‐generation lithium‐ion batteries (LIBs) due to their tunable chemistry, pore structure and abundant reaction ...sites. However, the pore structure of crystalline MOFs tends to collapse during lithium‐ion insertion and extraction, and hence, their electrochemical performances are rather limited. As a critical breakthrough, a MOF glass anode for LIBs has been developed in the present work. In detail, it is fabricated by melt‐quenching Cobalt‐ZIF‐62 (Co(Im)1.75(bIm)0.25) to glass, and then by combining glass with carbon black and binder. The derived anode exhibits high lithium storage capacity (306 mAh g−1 after 1000 cycles at of 2 A g−1), outstanding cycling stability, and superior rate performance compared with the crystalline Cobalt‐ZIF‐62 and the amorphous one prepared by high‐energy ball‐milling. Importantly, it is found that the Li‐ion storage capacity of the MOF glass anode continuously rises with charge–discharge cycling and even tripled after 1000 cycles. Combined spectroscopic and structural analyses, along with density functional theory calculations, reveal the origin of the cycling‐induced enhancement of the performances of the MOF glass anode, that is, the increased distortion and local breakage of the CoN coordination bonds making the Li‐ion intercalation sites more accessible.
A ZIF glass (melt‐quench Co ZIF‐62 glass), for the first time, is evaluated as anode for high performance lithium‐ion batteries. This ZIF glass anode exhibits an unusual capacity enhancement during charge‐discharge cycling. This exceptional phenomenon is related to the unique structure of ZIF glass, e.g., short‐range disorder.
Although metal-organic framework (MOF) glasses have exhibited high potential to be applied as anode materials for lithium-ion batteries (LIBs), their electrochemical performances still need to be ...greatly improved to match the rapid development of green energy technologies. Silicon is a promising candidate for the next generation of LIB anode but suffers from vast volume fluctuations upon lithiation/delithiation. Here, we present a strategy to in situ grow a kind of MOF, namely, cobalt-ZIF-62 (Co(imidazole)1.75(benzimidazole)0.25) on the surface of Si nano particles, and then to transform the thus-derived material into Si@ZIF-glass composite (SiZGC) through melt-quenching. The robust hierarchical structure of the SiZGC based anode exhibits the specific capacity of ∼650 mA h g-1, which is about three times that of pure ZIF glass and about six times that of pristine ZIF crystal at 1 A g-1 after 500 cycles. The origin of this huge enhancement is revealed by performing structural analyses. The ZIF glass phase can not only contribute to lithium storage, but also buffer the volume changes and prevent the aggregation of Si nano particles during lithiation/delithiation processes.
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•By encapsulating nano-Si into ZIF-62 glass, we made the composite anode for LIBs.•The encapsulation was realized by combining the reflux and melt-quenching methods.•The capacity of the composite anode is 3 times that of ZIF-62 glass based anode.•This capacity enhancement is achieved the synergy effect of nano-Si and ZIF glass.•The volume expansion and aggregation of Si powder is buffered by ZIF glass phase.
We investigate the thermal and electrochemical properties of xFe2O3‐(100‐x) P2O5 glass (x = 20, 30, 40, and 50 mol%) and 50Fe2O3‐50P2O5 (50FeP) glass‐ceramics as anodes for lithium‐ion batteries ...(LiBs). The results show that both the glass transition temperature and the energy bandgap monotonically decrease with the increasing Fe2O3 while a critical Fe2O3 content of 30 mol% is found to give glass the highest thermal stability, the largest capacity at 1 Ag‐1, and the lowest charge‐transfer resistance before cycling. Moreover, Fe3(P2O7)2 crystals formed during heat treatment in 50FeP glass effectively enhances the electrochemical properties. The optimum heat treatment condition for 50FeP glass is found at 1033 K for 4 h, that is, 1033 K‐4 h sample enables a reversible capacity of 237 mA h g−1 at the end of 1000 cycles at 1 Ag‐1, which is more than 1.5 times higher than that of the 50FeP glass‐based anode. These findings suggest that the Fe2O3‐P2O5 glass‐ceramics hold significant potential for the effective development of new types of glass anodes for future advanced LiBs.
•Water was introduced into a glass anode for Li-ion battery via humidity treatment.•This unconventional approach enhanced the anode capacity by > 200% at 1 Ag-1.•This effect arises from glass ...structure depolymerization and nanocrystal formation.•Humidity treatment boosted rate capability and cycling stability of the glass anode.
It is known that some oxide glass systems are a promising class of anode materials for lithium-ion Batteries (LIBs). However, the relatively low capacities of glass anodes severely limit their practical application for large energy storage devices. In this work, we establish an unconventional approach, by which the electrochemical performances of glass anodes for LIBs can be considerably enhanced. Specifically, we incorporate water into an electrochemically active glass system, i.e., TeO2-V2O5-P2O5 (TVP) glass powder via humidity treatment, and then mix the hydrated powder with additives to fabricate anode for LIBs. The optimized humidity treatment leads to the structural modification of the TVP glass powder, which boosts the lithium ion storage capacity of the TVP anode by more than 2.4 times, and maintains the reversible capacity for extra-long cycles. The boosted performances are attributed to both the depolymerized structural network for Li+ diffusion and the hydration-induced nanocrystals. These findings help develop superior glass electrodes in an economically effective way.
The oxide glass‐based anodes for lithium‐ion Batteries (LiBs) still suffer from two critical drawbacks, that is, low reversible capacity and low electrical conductivity. Here, we report a new way to ...overcome the two drawbacks. Specifically, we chose 50Fe2O3–50P2O5 (50Fe50P) glass as the anode material for LiBs, and then thermally treat it at 1118 K (Tg+345 K) for 0.5 h under reducing atmosphere (5 mol% H2+95 mol% Ar). The thermal reduction treatment led to formation of Fe2(P4O12) and Fe2Fe5(P2O7)4 crystals. The reduced glass‐based anode for LiBs exhibits the capacity of 373 mA h g−1 after 1 000 charge/discharge cycles at 1 A g−1, which is higher than that of the oxidized one. The reduction treatment greatly lowers the charge transfer resistance in the glass anode, indicating the enhancement of the electrical conductivity. This performance improvement could arise from the increase of accessible active sites for Li+ ion storage and transfer due to the existence of crystal–crystal/crystal–glass boundaries, as well as from the improvement of the electron transfer between Fe2+ and Fe3+ during cycling. This reduction–crystallization approach could help develop high‐performance oxide glass‐ceramics based anodes for advanced LiBs.
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