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Lithium metal, as the most ideal anode material for high energy density batteries, has been researched for several decades. However, the dendrite formation and large volume change during repetitive lithium plating/stripping lead to a serious safety issue and impede the practical application of lithium metal anode. Herein, a nanoporous Ni foam current collector with high surface area and surface flaws is constructed via a facile oxidation–reduction method. The inherent macropore structure of Ni foam can partly accommodate the volume variation during Li plating/stripping. The well-distributed nanopores on the skeleton of Ni foam can effectively reduce the local current density, regulate the uniform lithium nucleation and deposition with homogenous distribution of Li+ flux. Moreover, the surface flaws induce the formation of ring Li structures at initial nucleation/deposition processes and concave Li metal spontaneously formed based on the ring Li structures during cycling, which can direct the even Li plating/stripping. Therefore, highly stable Coulombic efficiency is achieved at 1 mA cm−2 for 200 cycles. The symmetrical cell, based on the nanoporous Ni foam current collector, presents long lifespans of 1200 and 700 h respectively at different current densities of 0.5 and 1 mA cm−2 without short circuit. In addition, the LiFePO4 full cell, with the Li metal anode based on the nanoporous Ni foam current collector, shows excellent cycling performance at 1C for 300 cycles and rate performance.

Converting solar energy efficiently into hydrogen is a promising way for renewable fuels technology. However, high-temperature heat transfer enhancement of solar thermochemical process is still a pertinent challenge for solar energy conversion into fuels. In this paper, high-temperature heat transfer enhancement accounting for radiation, conduction, and convection heat transfer in porous-medium reactor filled with application in hydrogen generation has been investigated. NiFe-Aluminate porous media is synthesized and used as solar radiant absorber and redox material. Experiments combined with numerical models are performed for analyzing thermal characteristics and chemical changes in solar receiver. The reacting medium is most heated by radiation heat transfer and higher temperature distribution is observed in the region exposed to high radiation heat flux. Heat distribution, O2 and H2 yield in the reacting medium are facilitated by convective reactive gas moving through the medium's pores. The temperature gradient caused by thermal transition at fluid-solid interface could be more decreased as much as the reaction chamber can store the transferred high-temperature heat flux. However, thermal losses due to radiation flux lost at the quartz glass are obviously inevitable.

Free-standing aligned fiber is capable of providing sufficient electrochemical properties for fiber electrode without sacrificing flexibility, which is highly desirable for fiber batteries that are expected to be flexible and efficient energy storage. Here, we propose a free-standing and aligned tungstate/MXene fiber spun from their mixed liquid crystals colloid for fiber-shaped lithium/sodium-ion batteries. Benefiting from the 3D interconnected ion transport tunnels, fast charge transfer frameworks and minimum ion-path tortuosity provided by the aligned structures of 2D tungstate and MXene nanosheets, the fiber is endowed with both efficient pseudocapacitive energy storage and flexibility. As expected, the fiber delivers high reversible capacity, excellent rate capability and outstanding long-term cycling performance. Even under mechanical deformations, the fiber batteries can power the LED, digital timer, temperature-humidity meter, and smart wristband. This work may promote the further development of practical fiber batteries for wearable electronics.

Nanoscale microstructure designing is playing an important role in improving the performance of electrode materials of an electrochemical battery. The Sn based anode is among the very high-capacity but less-stable materials, and has been used mostly for anode of the Li-ion battery with unsatisfactory performance. In this work, we design a new type of 3D porous graphene and nano-Sn composite (Sn/Void@G) by simple one-step annealing of graphene oxide, polystyrene spheres and stannic chloride for both high performance Li- and Na-ion battery anodes. More importantly, the 3D porous graphene formed tunable micro-nano void as a highly efficient “bumper” to accommodate the large volume expansion of nano-Sn particles. As results, the discharge specific capacity of the Sn/Void@G, anode still remains 45.3% while the charge-discharge current is increased 50 times, and the capacity is more than 400 mAh g−1 after 500 cycles at 5C rate. For Na storage, the integrated anodes deliver the Na storage capacity of 786.1 mAh/g at 0.1C rate and the capacity of more than 340 mAh/g after 800 cycles at 2C rate. The present result on Li and Na ion battery may pave the way to next generation high power and energy density batteries.

Although the properties of electrochromic materials (ECMs) have been enhanced using fabricated porous materials, the effect of materials porosity on such an enhancement remains unclear. Here, we report a novel ECMs with an adjustable pore hierarchy based on quasi-amorphous and ordered arrays of SiO2@Fc(COCH3)2. ECMs with different pore systems were generated by modifying Fc(COCH3)2 concentration and self-assembly temperature. The composition and core-shell structure of the SiO2@Fc(COCH3)2 nanospheres were confirmed through scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR) and EDX mapping. The influence of adjustable pore system on the electrochemical behavior was studied. Experimental results showed that the current density of the redox couple peaks of the quasi-amorphous porous SiO2@Fc(COCH3)2 films are considerably lower than those of the ordered porous films but are higher than those of the dense Fc(COCH3)2 films. At 550 nm, the transmittance variation of the quasi-amorphous porous SiO2@Fc(COCH3)2 film is 19%, whereas that of the ordered porous film is 35%. The coloration and bleaching times of the quasi-amorphous porous SiO2@Fc(COCH3)2 film are 17.1 s and 4.5 s, respectively, whereas those of the ordered porous film are only 16.5 s and 3.5 s, respectively. Furthermore, the porosities of the films are solved numerically by the finite-element method. For the ordered porous SiO2@Fc(COCH3)2 film, the porosity is 0.26, while the quasi-amorphous film became larger (0.31–0.41). This work is the first step in combining ferrocene derivative and colloidal crystal porous structures to develop a green, simple and efficient electrochromic process.

In this study, monolayer hollow spherical tungsten oxide (WO3) films have been prepared for the first time by magnetron sputtering combined with the colloidal crystal template method. Due to the large specific surface area, short ion diffusion distances, and weak scattering of the monolayer hollow structure, the hollow spherical WO3 film exhibits excellent electrochromic performance. This includes high transmittance modulation in the near-infrared spectral range (78.8% at λ = 1000 nm), fast switching response time (2.41 s for coloration and 1.28 s for bleaching), and high coloring efficiency (102.9 cm2 C−1) at 1000 nm. The results show that the hollow spherical WO3 film can effectively regulate incident light, especially in the near infrared band, which is not visible but has significant thermal effects.

In this study, camphorsulfonic acid (CSA)-doped polyaniline (PANI) films have been prepared on the surface of an Au/nylon 66 porous flexible substrate by electrochemical deposition. The feature of the research was that utilize an Au layer deposited onto a porous flexible substrate to deposite CSA-doped PANI film for modulation infrared emissivity at first time. The morphology of Au/nylon 66 flexible substrate and PANI films and the electrochromic properties of CSA-doped PANI film were investigated in detail to obtain a PANI film that possesses highly infrared modulation ability. The emissivity variation Δe was achieved as of 0.225, 0.399, and 0.426 in the wavelength ranges of 3–5, 8–12, and 2.5–25 μm, respectively. The switching times of the CSA doped-PANI film for the coloration and bleaching are 6 s and 2.5 s, respectively. The IR electrochromic film investigated in this work may find an application in IR devices for IR camouflage and thermal control.

Hard carbon with high special capacity has been widely studied as anode for sodium ion batteries (SIBs). Its storage sodium performance still needs to be further improved. Herein, a composite electrode was synthesized through growing V2O5 nanosheet array on free-standing hard carbon fiber fabric by solvothermal reaction. The electrochemical properties of the composite electrode were significantly enhanced compared with pure hard carbon fiber electrode. The composite showed a specific capacity from 241 mA h g−1 at 50 mA g−1 to 77 mA h g−1 at 1000 mA g−1 and a good cycling ability of 184 mA h g−1 after 100 cycles at 100 mA g−1. Except good storage Na ability for V2O5 nannosheets, the improvement of electrochemical performances also benefited from and the synergistic effect from the ability of fast electron transfer of hard carbon and the toleration for Na+ insertion of V2O5 nanosheet array, as well as the inhibitory effect on solid electrolyte interface (SEI) of nanostructure. Additionally, the free-standing electrodes could also increase the energy and power density. This will push the promising hard carbon material used as SIBs anode in practical applications.

Electrochromic-supercapacitors (ESCs) have shown great perspective in multifunctional smart devices due to their special function of monitoring the energy storage level by the visible color changes. However, the poor areal capacitance at high optical modulation(ΔT) and the inferior bifunctional lifespan hinder the practical application of ESCs. It is thus important to develop feasible ways to boost the optical-electrochemical properties and comprehend the corresponding inner mechanism. Inspired by nature’s conifer structure, herein, 3D hexagonal WO3 branched nanowire arrays/F-doped SnO2 (h-WO3 BNW/FTO) electrode have been successfully constructed via a single-step hydrothermal reaction followed by annealing process. Such biomimetic conifer-like structure is shaped by the separating crystal growth effect coupled with the specific topological structure of h-WO3. Benefiting from bionic structure, h-WO3 BNW/FTO electrode delivers a high areal specific capacity (0.0223 mAh cm-2) and large corresponding ΔT respond (80% ΔT at 650 nm) at 5 mV s-1, as well as outstanding optical-electrochemical cycle stability. Moreover, the aluminum storage mechanism during the optical-electrochemical process is affirmed using cyclic voltammetry and in-situ X-ray method. For practical application, the assembled ESC device based on the h-WO3 BNW/FTO electrode delivers a high 22.75 mF cm-2 areal specific capacitance, corresponding 45.81% ΔT (at 650 nm) and long-term bifunctional stability (over 90% bifunctional retention after 5000 cycles). Meanwhile, the visually monitoring capacity of the device is realized through the color changes. This study provides some insights into the biomimetic design for advanced bifunctional electrodes and the underlying mechanism affecting the electrochromic-charge storage performance.

Considering the increasing demands in energy storage systems (ESS), the nitrogen doped porous carbons with high volume properties are urgently needed in practical applications. Herein, we develop a new strategy for the fabrication of the high density and nitrogen-doped porous carbons (DNPCs) via low-temperature pyrolysis of phytic acid (PA)-doped polyaniline (PANI) coated on graphene, representing a high volumetric performance as supercapacitor electrode materials. PA is used to form the graphene oxide/polyaniline (GO/PANI) precursor, protect GO from agglomeration, reduce the porosity and regulate the heteroatoms contents of porous carbon. Benefiting from PA-inducing and low-temperature pyrolysis, the DNPC-500 performs a high volumetric capacitance of 643.7 F cm−3 at 0.5 A g − 1, and outstanding rate performance respectively. In a symmetric supercapacitor, the DNPC-500 device possesses a high volumetric energy density of 14.6 W L − 1 at the power density of 79.8 kW L − 1. Thus, this result exhibits a novel design of high density and nitrogen doped porous carbon materials for supercapacitors.

A flexible reflective-type electrochromic device based on PB films has been constructed. Based on the subtractive color-mixing theory, the demonstrated electrochromic device exhibits a unique reversible color changes from leaf-green to sand-yellow by electrochemical operation. Fast response time of 0.9 s for bleaching and 1.3 s for coloring is observed, which is faster than most reports. In addition, the device exhibits high electrochromic stability of more than 100 cycles without compromising its performance. The flexible device shows promise for a broad range of potential application in the wearable electrochromic displays and camouflage.

A NiOx film with varying crystallinity across film thickness has been prepared by reactive radio frequency magnetron sputtering. The main research achievement is that the electrochemical cycling stability of the NiOx film has been radically improved as compared with NiOx films deposited by the conventional technologies. At the same time, the optical modulation has been also improved, whereas other electrochromic parameters, such as the switching rate and high coloration efficiency have been preserved at the required level.

A novel V2O5@PANI composite nanowires were prepared by simply stirring in sodium nitrate solution and in-situ chemical oxidation polymerization methods. The V2O5@PANI composite nanowires display excellent optical and electrochemical properties, such as multicolor ranging from black, pale yellow, light yellow to dark green, outstanding cycling stability for 1000 cycles and fast switching time of bleaching and coloration (1.5 and 2.3 s, respectively). These outstanding performances are attributed to the synergistic effect between PANI encapsulated and original V2O5 nanobelts. The study offer a new synthesis strategy for fabricating inorganic-organic composite materials in optical and electrochemical fields. The morphology and structure of the composite were characterized by scanning electron microscopy, high-resolution transmission electron microscopy and X-Ray photoelectron spectroscopy.

High-capacity anode materials for lithium ion batteries (LIBs), such as Ge, generally suffer tremendous volume changes, as a result of the conversion reaction mechanism with Li, severely impede the high rate and cycling performance toward their practical application. In this article, we demonstrate a general LIBs Ge composites electrodes fabrication method using electrodeposition from room temperature ionic liquid. Our process is capable of forming composites electrodes with carbon nanotubes (CNTs), reduced graphene oxide (RGO), poly (3,4-ethylenedioxythiophene) (PEDOT), without the additives and conductive agents. During the electrodeposition process, Ge nanoparticles are integrated into the substrate network. Benefiting from the porosity, conductive network and mechanical stability constructed by interpenetrated compound layers, the hybrid system synergistically enhances the intrinsic properties of each component, yet is robust and flexible. The Ge/CNTs, Ge/RGO and Ge/PEDOT composites retain capacities of ∼851, 1212, and 1300 mAh/g after 200 cycles at 0.1 C. SEM analysis suggests that Ge/PEDOT composites have flower-like hierarchically porous structure, during cycling this structure transforms into a porous network, which can mitigate the physical strains during the Li uptake/release process, and increase the interfacial contact area with organic electrolyte. Consequently, the Ge/PEDOT composites demonstrate greatly enhanced rate capability without obvious capacity fading at high rate of up to 5 C.

We present a facile method to prepare W - doped VO2 films with lowered phase transition temperature (Tt), narrowed hysteresis loops width (ΔTt) and excellent cycle stability. The W - doped VO2 films have been obtained by inorganic sol - gel method. And W dopant is introduced by pouring melt V2O5 into ammonium tungstate solution. The properties of the samples are measured by XRD, XPS, SEM and transmittance spectra. The Tt is reduced from 73 °C to 20 °C along with the ΔTt narrowed from 10 °C to 4 °C as W dopant increasing from 0 to 3.2 at%. Besides, no obvious attenuation is observed on crystal structure, variation of transmittance (ΔT2000nm), Tt and ΔTt for W - doped VO2 films after 550 alternate heating and cooling cycles, while the pure VO2 films show obvious degradation. Since the surface morphology has no obvious changes after 550 cycles, it suggests that the W dopant induced distorted crystal structure strengthen the cycle stability of W - doped VO2 films. These encouraging results show great potential and understanding of VO2 films for practical applications.

Sodium-ion hybrid supercapacitors have received great attracts for next-generation energy storage applications due to their high energy and power densities, as well as the abundant sodium resource. However, electrodes based on transition-metal oxides often suffer from low reversible capacity and sluggish redox kinetics, which seriously constrains the rate and cycling performance of the devices. Herein, a facile two-step hydrolysis synthesis is used to prepare uniform sandwich-like mesoporous Nb2O5/graphene/mesoporous Nb2O5 (G@mNb2O5) nanosheets as sodium storage materials. The mesoporous Nb2O5 layers on graphene are constructed by several nanometer-sized Nb2O5 particles. In virtue of the structural features, the G@mNb2O5 nanosheets electrode demonstrates high-rate capacity (293 and 125 mA h g−1at 50 and 2000 mA g−1, respectively) and stable cycling performance due to the rapid redox kinetics, including significantly increased surface pseudocapacitive contribution, improved sodium-ion diffusion coefficient, and short characteristic relaxation process. By employing activated carbon as cathode, a full sodium-ion hybrid device successfully demonstrates a high energy density of 56.1 Wh kg−1 at 120 W kg−1, and 9.7 Wh kg−1 at 7200 W kg−1, as well as a stable capacitance retention of ∼ 89% at 1 A g−1. The availability of capacitive Na-ion storage system presented here is attractive for cost-effective energy storage applications.

The level energies of diatomic molecules calculated by the frequently used Dunham expansion will become less accurate for high-lying vibrational and rotational levels. In this paper, the potential curves for the lower-lying electronic states with accurate spectroscopic constants are reconstructed using the Rydberg–Klein–Rees (RKR) method, which are extrapolated to the dissociation limits by fitting of the theoretical potentials, and the rest of the potential curves are obtained from the ab-initio results in the literature. Solving the rotational dependence of the radial Schrodinger equation over the obtained potential curves, we determine the rovibrational level energies, which are then used to calculate the equilibrium and non-equilibrium thermodynamic properties of N2, N 2 + , NO, O2, CN, C2, CO and CO+. The partition functions and the specific heats are systematically validated by available data in the literature. Finally, we calculate the radiative source strengths of diatomic molecules in thermodynamic equilibrium, which agree well with the available values in the literature. The spectral radiative intensities for some diatomic molecules in thermodynamic non-equilibrium are calculated and validated by available experimental data.

Polyimide (PI) film is usually considered as a valuable pyrolysis precursor of graphitized films applied in various electrodes and batteries. In this work, reduced graphene oxide (RGO) sheets were chosen as the catalysts to improve the graphitization properties of PI film. To analyze the structural evaluations, the crystalline growth process with RGO increasing was carefully investigated by transmission electron microscope (TEM) and the crystalline sizes were calculated by X-ray diffraction (XRD) and Raman spectra. The obvious induced effects were confirmed in graphitization of RGO/PI composites at 2300 °C. Finally, the electrical properties of as-prepared RGO/graphite composites were also improved with RGO increasing.

Stretchable electrochromic devices (SECDs) have steadily attracted widespread attention in wearable devices. However, the delamination of device architectures (electrochromic layer, conductive layer and substrate) and poor chemical stability of conductive layer (silver nanowires (AgNWs)) are the key issues to be resolved to ensure the practical applications of flexible electrochromic devices. Herein, we designed a flexible and stretchable WO3@AgNW-PrePDMS (Pre-cured Polydimethylsiloxane) electrode, through integrated and embedded design, to build a high-performance electrochromic device. The integration of electrochromic layer and conductive layer in the electrode is fabricated via a WO3@AgNW core–shell structure. And embed the core–shell structure into the flexible substrate PDMS to form WO3@AgNW-PrePDMS electrode. This electrode architecture can prevent the delamination of the stretchable electrode during bending tests. Moreover, WO3 as a shell structure protects the conductive material AgNW to prevent its oxidation and improve the stability of the conductive substrate. The WO3@AgNW-PrePDMS electrode displays outstanding electrochemical stabilities and excellent bi-functionalities (flexible conductive film and electrochromic electrode): high conductivity (12 Ω/sq) as flexible transparent conductive film and wide optical modulation range (ΔT = 72% at 550 nm) as electrochromic electrode. The stretchable WO3@AgNW-PrePDMS electrode can still maintain stable electrical conductivity (ΔR/R≈8.3% and 14%) and electrochromic performance (90% and 92% retention) after 20,000 bending cycles and stretching to 70%, indicating the excellent mechanical flexibility. The WO3@AgNW core–shell nanowire network electrodes with embedded structures can be a strong candidate for wearable electrochemical energy devices in the future.

Electrochemical CO2 conversion into useful products using renewable electricity is a promising route to mitigate the potential challenges regarding large CO2 emissions into the environment. However, there are limitations in accomplishing its practical utilization. Recently, many efforts have been made into increasing electrochemical CO2 reduction (ERC) performance using Pd-based catalysts. The Pd-based materials have exhibited unique electrocatalytic characteristics for ECR since they can convert CO2 to HCOOH and CO with high selectivity at equilibrium potential and certain negative potential range, respectively. This review provides useful insights into the recent progress made on Pd-based electrocatalysts. Different factors of Pd-based catalysts influencing ERC performance, such as the effect of size, alloy, morphology, load, and core–shell have been discussed in detail. In the end, future prospects of Pd-based catalysts have been included to briefly highlight the important future considerations of this rapidly growing technology.

The high specific capacity and cycle stability of Li-ion alloy anode materials have been the focus of researchers. However, the alloy anode materials are easy to be broken and cracked after cycling. In this study, we have co-electrodeposited Al-Ga composite from ionic liquid, and the obtained composite has a higher specific capacity and the longer cycling life than single Ga/Al electrode. Initial discharge capacity is 1554.7 mAh/g, and Coulombic efficiency is 82.6% at 0.1 A/g. Co-electrodeposited Al-Ga composite from ionic liquid provides a new way to solve the electrode materials that are easily fractured and cracked after cycling, and improves cycle stability and high capacity to a certain extent.

Two-dimensional (2D) transition metal oxide composited with graphene has attracted worldwide attention in the energy storage and conversation field. Here, a 2D rGO/NiO heterostructure film on ITO glass was designed and applied to electrochromic energy storage. The 2D heterostructure increases the interlayer spacing of the NiO-based films and the electrochemically active surface area, reduces the charge transfer resistance and band gap, and then realizes fast ion diffusion and electron transport, thus improving the electrochromic and supercapacitor performance of the NiO film. The film exhibits outstanding areal capacitance (269 mF cm−2 at current density of 0.5 mA cm−2), excellent cyclic stability (capacitance retention almost 100% after 1000 cycles at current density of 1.5 mA cm−2) and superior electrochromic performance (high optical contrast of 53% at 630 nm, fast response time of 3.4 s for coloration and 5.3 s for bleaching). Furthermore, integrated the 2D heterostructure rGO/NiO film into a smart electrochromic-supercapacitor device, two devices could light up an electronic watch for about 2 h, at the same time, the color of the device changes in the process of electric output.

Accurate radiative transition probabilities of diatomic electronic systems are required to calculate the discrete radiation of plasmas. However, most of the published transition probabilities are obtained using older spectroscopic constants and electronic transition moment functions (ETMFs), some of which deviates greatly from experimental data. Fortunately, a lot of new spectroscopic constants that include more anharmonic correction terms than the earlier ones have been published over the past few years. In this work, the Einstein coefficients, Franck–Condon factors and absorption band oscillator strengths are calculated for important diatomic radiative transition processes of N2-O2, CO2-N2 and H2 plasmas produced in entering into the atmosphere of Earth, Mars and Jupiter. The most up-to-date spectroscopic constants are selected to reconstruct the potential energy curves by the Rydberg–Klein–Rees (RKR) method. Then the vibrational wave functions are calculated through the resolution of the radial Schrodinger equation for such potential energy curves. These results, together with the latest “ab-initio” ETMFs derived from the literature are used to compute the square of electronic-vibrational transition moments, Einstein coefficients and absorption band oscillator strengths. Moreover, the Franck–Condon factors are determined with the obtained vibrational wave functions. In the supplementary material we present tables of the radiative transition probabilities for 40 band systems of N2, N 2 + , NO, O2, CO, CO+, CN, C2 and H2 molecules. In addition, the calculated radiative lifetimes are systematically validated by available experimental results.

In study, we proposed a simple yet fast optical sensing motif based on thimbleful of polyvinyl alcohol (PVA) infiltrated photonic crystal (PC), which allows for high efficiency in vapor sensing through changes in their inter-layer space. Linear response to a broad dynamic range of vapor concentration was realized. Ultrafast response time (

A bowl-like polyaniline (PANI) film is synthesized by the combination of electrodeposition and monolayer colloidal crystal template (MCCT). The resulting film exhibits an ordered hexagonal close-packed bowl-like arrangement that is made up of macrobowls with a diameter of 450 nm. The unique bowl-like structure endows PANI film with enhanced electrochromic performances due to its increased accessible intercalation sites originating from larger surface areas and shortened diffusion distances of ions resulting from macroporous structure. It is found that the bowl-like PANI film possesses faster switching responses (1.45 s for coloration and 0.62 s for bleaching), larger optical transmittance modulation (52.1% at 740 nm) and higher coloration efficiency (118.2 cm 2 C −1 ) than the dense PANI film prepared without the MCCT. Moreover, the bowl-like film also exhibits IR electrochromic performances in the wavelength range from 2.5–25 μm, which depicts a reflectance modulation ∼ 36.5% at 10 μm. This work provides a promising strategy for constructing other bowl-like polymer electrochromic films.

In this study, dodecylbenzene sulfonate acid (DBSA) doped-polyaniline (PANI) films were synthesized in situ on Au/porous flexible substrate by electrochemical deposition. The emissivity change (△e) data of PANI films show a reversal from positive to negative as the polymerization charge increases. This trend can be explained by using the Drude free electron theory and the Hagen-Rubens approximation at low frequency due to the pseudo-metallic behavior of conducting polymers. The DBSA doped-PANI film was used as an active layer to fabricate an infrared (IR) electrochromic device. The △e of this IR electrochromic device was measured to be 0.183, 0.388, and 0.315 in the wavelength ranges of 3–5 µm, 8–12 µm, and 2.5–25 µm, respectively. IR thermal images visually obtained from an IR thermal imager suggest that the IR electrochromic device possesses regulating capacity of thermal radiation within the operating waveband of the instrument (7.5–14 µm). The IR electrochromic device developed in this work can be potentially used in IR camouflage for military and thermal control for satellite.

α-Fe2O3@SiO2/Au core-shell ellipsoids, applied as the structural units of non-spherical photonic crystals, have the excellent monodispersity and self-assembly capacity. To improve the interfacial effect, the α-Fe2O3@SiO2 ellipsoids were modified by 3-aminopropyl triethoxysilane (APS) and used as the adsorption center of Au nanoparticles (NPs), which were synthesized by a sodium citrate reduction method. The adsorption behavior of α-Fe2O3@SiO2/Au ellipsoids was comprehensively investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The variations of optical properties were further evaluated by ultraviolet and visible (UV–vis) and Raman spectroscopy. The α-Fe2O3@SiO2/Au core-shell ellipsoids exhibited the excellent UV–vis absorption and Raman scattering effects, which were suggested to potentially apply in photothermal and photoelectric conversation.

Flexible transparent conductive films (FTCFs) have attracted tremendous concern because it is a key component of next generation electronics and optoelectronic devices. Silver nanowires (AgNWs) random networks have become the most promising candidates for FTCFs, with high transmittance, low sheet resistance, and excellent mechanical flexibility. However, there are many barriers to the application of FTCFs based on AgNWs, such as easy oxidization and weak adhesion to the substrates. Here, we developed a facile approach to fabricate AgNW-C core–shell nanowires derived from the carbonization of glucose by a one-pot solvothermal method. A uniform amorphous carbon shell coating improves the chemical stability of AgNWs and the hydroxyls on the surface of the nanowires enhance the adhesion to the substrate. The AgNW-C/poly(ethylene terephthalate) (PET) transparent conductive film shows excellent robustness when subjected to bending (ΔR/R0 ≈ 2.8% after bending 2000 times). Besides, the conductivity of AgNW-C/PET film remains relatively stable after 100 peeling-off cycles by a 3 M tape test. A flexible electrochromic device (FCD) has also been constructed based on the AgNW-C/PET film, which shows promising stability and mechanical flexibility due to the remarkable electrochemical stability and mechanical strength of the AgNW-C/PET films. The results present the significant potential applications of the flexible transparent device based on AgNW-C/PET film for many fields in the future.

Some animals, such as the chameleon, have great capability of camouflage by changing their skin color to avoid detection. This outstanding property have inspired researchers to develop the ability of the materials and devices to mimic chameleon for applications in intelligent wearable and camouflage devices. Tungsten oxide (WO3), switching between blue and transparent, is widely studied due to its large optical modulation but it is difficult to obtain multicolor and flexibility. Here, we design a bio-inspired chameleon skin electrochromic device (ECD) assembled by inorganic electrochromic materials WO3, which can achieve the reversible color changes from yellow, light green to dark green according to subtractive color mixture theory. The flexible ECD exhibits a high optical reflectance modulation of 38.9% at voltage of ± 1.5 V in the wavelength range of 250–2500 nm. Fast response speed of 0.32 s for both coloring and bleaching process is obtained which can be attributed to the porous structure of the WO3 electrochromic layer. The ECD keeps excellent electrochromic performance even under bending conditions, indicating the great flexibility. The inorganic bio-inspired chameleon skin ECD opens new avenues for the design of intelligent and wearable devices.

Electrochromic （EC） devices have many important commercial applications ranging from car rear-view mirrors, e-paper, sunglasses, to architectural smart windows. The corrosiveness of acid and the unsafety of Li+ based electrolyte are the significant issues that restrict the performance and large-scale application of EC devices. The bivalent cation Mg2+ has been proved to be efficient EC insertion ion to solve these issues. In this study, the WO3 films are deposited on ITO glass substrates by electron beam evaporation and the influence of annealing on the structure, morphology and optical properties are studied. The diffusion coefficient of Mg2+ in WO3 films is 10−11–10−10 cm2/s, and decreases with increase of annealing temperature. The WO3 films annealed at 200 °C shows the lager ΔT and long-term cyclic stability. Meanwhile, the ΔT of EC device with the structure of Glass/ITO/WO3/MgCl2 liquid Electrolyte/ITO/Glass is approximately 34.6%. These findings provides huge support for the application of Mg2+ based electrolyte in the new generation of EC devices.

The widespread use of the flexible infrared electrochromic device (IR-ED) fundamentally depends on not only the IR emissivity modulation ability of the functional layer but the component assembling structures. However, building integrated assembling structure for excellent flexibility and service life is an urgent but a challenging task due to exfoliation of the components of the traditional sandwich structure IR-ED during the use of bending and folding. Herein, we employed both sides of gold-plated nylon porous membrane as ion transport layer and electrode layer to construct highly-flexible monolithic integrated IR-ED. The dodecyl benzene sulfonate acid (DBSA)-doped PANI films were electrodeposited on the both side of gold-plated nylon porous membrane. Then the electrolyte was filled into the nylon porous membrane to successfully construct the highly-flexible monolithic integrated IR-ED. Compared with the traditional sandwich structure IR-ED, the unique configuration endows excellent IR electrochromic performance, ultra-high flexibility and structural stability. The monolithic integrated IR-ED can reversibly convert between colored state (dark green) and bleached state (golden yellow) upon the imposed external voltages, and the IR emission modulation of 0.43 and 0.40 is obtained at the wavelength ranges of 8–14 µm and 2.5–25 µm. The illustrated capabilities make the highly-flexible monolithic integrated IR EC device promising for thermoregulation related technologies and adaptive camouflage platforms.

Annealing temperature has a significant influence on the performances of the electrochromic films and devices, such as optical transmittance modulation, response time and cyclic stability. Although there are lots of reports on the effect of annealing temperature on the performance of monolayer, the relationship between annealing temperature and electrochromic devices (ECDs) is rarely studied. Here, all-solid-state ECDs glass/ITO/NiO/ZrO2/Li/WO3/ITO are prepared by evaporation method and annealed at different temperature from 200 °C to 400 °C. The results show that the cyclic stability of the ECDs has a strong association with the annealing temperature. The ECDs annealed at low temperature suffer from poor cyclic stability because of the irreversible insertion of Li ions in WO3 layer. The ECD annealed at 400 °C exhibits superior stability with high optical modulation of 50.2% even after 50000 cycles at wavelength of 400–1050 nm. The influence mechanism of annealing temperature on the ECDs is analyzed which has great value for practical application.

Herein, LiAlSiO4 was used as electrolyte material for all-solid-state electrochromic devices for the first time, and an electrochromic device (ECD) with the structure of glass/ITO/NiO/Ta2O5/LiAlSiO4/Ta2O5/WO3/ITO was prepared by magnetron sputtering method. Since LiAlSiO4 electrolyte exhibits high transparency and good ionic conductivity, the ECD shows good electrochromic performance including: large optical transmittance modulations (50.8% at 586 nm, 64.1% at 1000 nm), good stability (optical modulation is still maintained at 81.4% (586 nm) and 89.0% (1000 nm) of initial state after 1000 cycles) and high coloration efficiency (60.3 cm2 C−1 at 586 nm, 150.6 cm2 C−1 at 1000 nm). Considering the low cost and abundance of Al and Si, LiAlSiO4 may be acknowledged as a sustainable electrolyte for future high-performance ECDs.

In this study, solar thermal power coupled with a direct irradiated solar thermochemical reactor using porous-medium NiFe2O4@ZrO2 oxygen exchange material was investigated by combining experiments to the numerical models. The ability of ZrO2, NiFe2O4, and NiFe2O4@ZrO2 to release/uptake O2 and their CO2-splitting characteristics are analyzed by the thermogravimetric analyzer (TGA) and the microstructural changes and chemical composition of NiFe2O4@ZrO2 are examined by scanning electron microscopy (SEM) and x-ray energy dispersive spectrometer (EDS). The experiment performed with a redox thermochemical reactor under a high-flux solar spectrum resulted in a total of 337.89 mL of CO collected during 46 min of CO2-splitting over NiFe2O4@ZrO2 redox material. Higher CO2-splitting activity of NiFe2O4 resulting in 186.545 μmol/g and 130.707 μmol/g of CO yield at 1293-795 °C and 100 sccm of CO2 flow rate were obtained by TGA at the first and second cycle, respectively. The results of both experiments showed significant CO yield at the early stages of oxygen carriers’ re-oxidation with CO2. This study provided important results that could have significant contributions to the solar thermochemical energy storage and CO2 chemical transformation processes.

With the development of high-frequency and high-speed flexible circuit boards, there are growing demands for low dielectric constant materials with high mechanical and electric breakdown strength. Herein, a novel sandwich structure is successfully fabricated using fluorinated graphene/polyimide (FG/PI) composite film as a dense outer surface layer and porous PI film as the middle layer. The middle porous layer lead to the ultra low dielectric constant. The presence of FG/PI layers resulted in the increase of mechanical and dielectric breakdown performance compared to that of porous PI. Especially, the three-layer FG/ PI film showed a tensile strength of 65.76 MPa, a tensile modulus of 2.96 GPa, a characteristic breakdown strength of 170.49 kV/mm, a dielectric constant of 1.92, and a dielectric loss of less than 0.003. Therefore, the sandwich structure PI film is a highly prospective candidate as flexible circuit substrates for electronics and microelectronics devices.

Due to the dependent scattering and absorption effects, the radiative transfer equation (RTE) may not be suitable for dealing with radiative transfer in dense discrete random media. This paper continues previous research on multiple and dependent scattering in densely packed discrete particle systems, and puts emphasis on the effects of particle complex refractive index. The Mueller matrix elements of the scattering system with different complex refractive indexes are obtained by both electromagnetic method and radiative transfer method. The Maxwell equations are directly solved based on the superposition T-matrix method, while the RTE is solved by the Monte Carlo method combined with the hard sphere model in the Percus-Yevick approximation (HSPYA) to consider the dependent scattering effects. The results show that for densely packed discrete random media composed of medium size parameter particles (equals 6.964 in this study), the demarcation line between independent and dependent scattering has remarkable connections with the particle complex refractive index. With the particle volume fraction increase to a certain value, densely packed discrete particles with higher refractive index contrasts between the particles and host medium and higher particle absorption indexes are more likely to show stronger dependent characteristics. Due to the failure of the extended Rayleigh-Debye scattering condition, the HSPYA has weak effect on the dependent scattering correction at large phase shift parameters.

Graphene has been extensively investigated as anode material for Li and Na ion batteries due to its excellent physical and chemical performance. Herein, we report a new member of ‘graphene family’, a reduced graphene nanowire on three-dimensional graphene foam (3DGNW). The novel graphene nanowires were synthesized via a template strategy involving reduction and assembly process of nanosized graphene oxides (nGO), pyrolysis of polystyrene spheres (PS) template and catalytic reaction between GO and PS decomposition products. When evaluated as anodes material for Li and Na ion batteries, the 3DGNW exhibits relatively low discharge-voltage plateau, excellent reversible capacity, rate capability, and durable tolerance. For anode of Na ion batteries, a reversible capacity of more than 301 mAh g −1 without capacity fading after 1000 cycles at rate of 1 C were achieved. Even at rate of 20 C, a high reversible capacity of 200 mAh g −1 can be retained. The superior electrochemical performance is ascribed to hierarchical multidimensional graphene architecture, high graphene crystallinity, expansile graphene interlayer distance, and extensively lateral exposed edges/pores, which can promote the electron and ion transport. The realization of assembling reduced graphene sheets to graphene nanowire offers new opportunities for energy storage application of graphene based assembly in future.

S urface- e nhanced R aman s cattering (SERS) is a high resolution approach for organic molecule detections. Under a controllable magnetic field, γ-Fe 2 O 3 @SiO 2 ellipsoids could be forced by the solvent evaporation and assembly to shape the γ-Fe 2 O 3 @SiO 2 ellipsoid ordered arrays. Sputtering the thin gold film onto the ordered arrays, we could fabricate the gold/ellipsoid ordered complex films. The outstanding SERS could be observed using 4- m ercapto b enzoic a cid (MBA) as the probe molecule, where the detected limit concentration is lower than 10 −7 mol/L.

Innovative WO3·2H2O/PEDOT films with strong adhesion of the electrochromic layer and the substrate were fabricated. A WO3·2H2O/PEDOT electrochromic layer can be firmly fixed to an ethylene vinyl acetate/polyethylene terephthalate (EVA/PET) electrode using Ag as the conductive layer by a transient heating method. The electrochromic film is mechanically robust and can be twisted, folded and crumpled without performance degeneration. Improved performance has been realized by WO3·2H2O/PEDOT films compared with WO3·2H2O films due to the excellent electrical conductivity of PEDOT, including a higher of Li-ion diffusion coefficient (1.1×10−9 cm2 s−1), faster response time (2.6 s for bleaching time and 4.4 s for coloration time), higher color efficiency (180.2 cm2 C−1) and larger transmittance modulation (63.1%) at 956 nm. The results are very promising for the next generation of deformable or implantable hidden message displays and wearable smart clothes applications.