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Electrolyte plays an essential role in ion transport among all electrochemical energy storage systems (EESs). Water-in-Salt (WIS) electrolyte as a novel aqueous electrolyte has attracted wide attention in recent years because it maintains the advantages of aqueous electrolytes and the wide electrochemical stable voltage window of nonaqueous electrolytes. In this review, we first summarized the structure, properties, and applications of the original LiTFSI-based WIS electrolyte. Then, we special emphasized the effects of ion and additional phase regulation on the structure and performance of WIS electrolytes based on the characteristic of different ions and additional phases in WIS electrolytes. Furthermore, the future research directions and opportunities of different WIS electrolytes are prospected. This review aims to provide guidance and reference for designing and manufacturing the next generation of aqueous electrolytes used in different EESs.

Porous carbon is considered as one of the most promising electrode materials for supercapacitors. In this work, we report a simple two-step preparation of porous carbon materials based on MnO2-coated and N-doped pinecone, which was synthesized by carbonization and hydrothermal process. After electrochemical analysis, the prepared 3-N-PC@MnO2 electrode exhibited optimal electrochemical performance. At a current density of 1 A/g, the specific capacitance of 3-N-PC@MnO2 was as high as 167.8 F/g in a voltage window of 0–1 V. After being assembled into an asymmetric supercapacitor with the PVA/Na2SO4 quasi-solid electrolyte under the current density of 1 A/g, the energy density could reach 20.42 Wh/kg, the power density could achieve 799.9 W/kg, and its capacitance remained 84.5% after 3000 cycles, showing remarkable electrochemical performance.

Heterostructure devices based on two-dimensional materials have been under intensive study due to their intriguing electrical and optical properties. One key factor in understanding these devices is their nanometer-scale band profiles, which is challenging to obtain in devices. Here, we use a technique named contact-mode scanning tunneling spectroscopy to directly visualize the band profiles of MoS2/WSe2 heterostructure devices at different gate voltages with nanometer resolution. The long-held view of a conventional p-n junction in the MoS2/WSe2 heterostructure is reexamined. Due to strong inter- and intralayer charge transfer, the MoS2 layer in contact with WSe2 is found to convert from n-type to p-type, and a series of gate-tunable p-n and p-p+ junctions are developed in the devices. Highly conductive edges are also discovered which could strongly affect the device properties.

A miniature ionization vacuum sensor (IVS) based on an on-chip SiOx-based tunneling electron source is reported. The vacuum sensor fabricated by microfabrication technologies exhibits a compact multilayered structure with overall dimensions of $13\times 9\times2.7$ mm3, where the electron source chip, Si layer of the electron collector, Si layer of the ion collector, and glass spacers between them are stacked together by an anodic bonding method. Electron impact ionization occurs in a semiclosed cavity through the electron and ion collector layers and glass spacers. Because of the compact structure, low working voltage of SiOx-based tunneling electron sources, and stable electron emission of the electron sources in a poor vacuum, a wide linear detection range from $1.3\times 10^{-2}$ to 133 Pa and a sensitivity of $8.3\times 10^{-4}$ Pa−1 have been demonstrated for the devices. These advantages, including miniature size, a detection range up to the rough vacuum regime, and the capability of batch fabrication with microfabrication technologies, make our IVSs promising in vacuum measurements.

Currently, the practical application of SiOx still has a huge hindrance in the area of lithium ion battery, because it is unable to achieve an effective contact with surrounding conducting materials, resulting in failure to form lithium ion migration tunnels. In this work, we presented a facile method to synthesize the B-doped SiOx composite by adhering SiOx particles with MWCNT (multi-walled carbon nanotube) under the assistance of lithium metaborate (LiBO2). LiBO2, as a sintering aid, not only can react with SiOx to form a compacted framework, but also build a three-dimensional (3D) conductive network for ions transportation. Furthermore, B-SiOx@CNT@LBO anode delivers a remarkable lithium storage performance in terms of long cycles and high rate capability. A full cell coupled with NCM622 cathode achieves a high energy density of 429.5 Wh kg−1 based on the total mass of cathode.

Quality and property control have become one of the critical problems for the metallic parts produced by selective laser melting. In this paper, the crack spontaneously formed in the Ti-6Al-4V alloy by selecting laser melting is investigated. The crack is C-shape without branching in macro view. In micro view, the crack originates from and propagates toward the selective laser melting (SLM) processing defects. The crack surface topography shows that the crack is typical dimple cleavage. A few heads of martensitic α′ laths appear at the bottom of the dimple. And the secondary crack nucleates and grows up near by the martensitic α′ laths. A lot of spatters and cavities formed at the top surface of the SLM body and the residual stress accumulated in the SLM body is up to 640 MPa, which confirms that the SLM processing defects and the residual stress induced the origination and propagation of the crack. The research results indicate that preventing spatter and controlling residual stress are important to SLM processing.

A novel green composite flame retardant, bismuth oxychloride nanosheet decorated with chitosan and phytic acid (BiOCl@CS-PA) was prepared in order to improve the fire safety of flexible poly(vinyl chloride) (PVC). Introducing phytic acid (PA) is aimed at promoting the flame retardancy of BiOCl nanosheets in condensed phase using the synergistic effects. Chitosan (CS) not only acts as a bridge between BiOCl and PA, but also increases residue as a charring agent. Adequate characterizations verified that the BiOCl@CS-PA has been prepared successfully. When 3 wt.% of BiOCl@CS-PA was imparted into the PVC matrix, the resultant PVC composite can pass V-0 rating in the UL-94 test. Additionally, cone calorimetry test demonstrated that 3 wt.% of BiOCl@CS-PA reduced the first peak heat release rate and inhibited the pronounced peak heat release rate of PVC matrix between 300–400 s in comparison with the BiOCl nanosheets, indicating a further improvement in flame retardancy of PVC/BiOCl@CS-PA composite with the help of PA in the condensed phase. Microstructure and morphology of the char residue of PVC/BiOCl@CS-PA were analyzed to reveal the flame retardant mechanism. The results indicated that the joint action of PA and CS improves the quality of the char layer, which contributes to improving the flame retardancy in condensed-phase.

This paper reports a 3-dimentional (3D) pressure sensor based on surface acoustic wave (SAW) resonators. The SAW resonators were designed and fabricated on 128°Y-X LiNbO3 substrate using the MEMS technology. The pressure sensing structure was 3D-printed using polyactic acid plastic, and two SAW resonators were integrated in the 3D-printed chamber structure for both temperature and pressure sensing. The SAW-based gas pressure sensors demonstrate a sensitivity of 589 ppm/MPa at the pressure range of 100-600 kPa and temperature of 40 °C.

Vertical transistors—in which the channel length is determined by the thickness of the semiconductor—are of interest in the development of next-generation electronic devices. However, short-channel vertical devices are difficult to fabricate, because the high-energy metallization process typically results in damage to the contact region. Here we show that molybdenum disulfide (MoS2) vertical transistors with channel lengths down to one atomic layer can be created using a low-energy van der Waals metal integration technique. The approach uses prefabricated metal electrodes that are mechanically laminated and transferred on top of MoS2/graphene vertical heterostructures, leading to vertical field-effect transistors with on–off ratios of 26 and 103 for channel lengths of 0.65 nm and 3.60 nm, respectively. Using scanning tunnelling microscopy and low-temperature electrical measurements, we show that the improved electrical performance is the result of a high-quality metal–semiconductor interface, with minimized direct tunnelling current and Fermi-level pinning effect. The approach can also be extended to other layered materials (tungsten diselenide and tungsten disulfide), resulting in sub-3-nm p-type and n-type vertical transistors. Molybdenum disulfide vertical transistors with channel lengths down to one atomic layer can be made with metal electrodes using a mechanical van der Waals transfer process that leads to a high-quality metal–semiconductor interface.

Approaches to achieve stable perovskite nanocrystals (PNCs) of interest, in particular those with large structural anisotropy, through protective coating of the inorganic shell at a single-nanocrystal (NC) level are comparatively few and limited in scope. Reported here is a robust amphiphilic-diblock-copolymer-enabled strategy for crafting highly-stable anisotropic CsPbBr3 nanosheets (NSs) by in situ formation of a uniform inorganic shell (1st shielding) that is intimately ligated with hydrophobic polymers (2nd shielding). The dual-protected NSs display an array of remarkable stabilities (i.e., thermal, photostability, moisture, polar solvent, aliphatic amine, etc.) and find application in white-light-emitting diodes. In principle, by anchoring other multidentate amphiphilic polymer ligands on the surface of PNCs, followed by templated-growth of shell materials of interest, a rich variety of dual-shelled, multifunctional PNCs with markedly improved stabilities can be created for use in optics, optoelectronics, and sensory devices.

Although the quality inspection method of polycarboxylate superplasticizers (PCE) based on macroperformance is still widely used, it has the drawbacks of time-consuming and low precision. This study aims to develop a practicable alternative method for quality inspection of PCE. For this, spectra collection, feature extraction, and cluster analysis were performed up on the PCE samples to demonstrate the feasibility of the method. Also, a new similarity calculation method was introduced in this work. Results show that the solid PCE sample for spectrum collection can be prepared using the simple heating method. High-quality spectra can be rapidly collected by infrared spectrometer combined with ATR accessory. Meanwhile, the accuracy of classification and clustering is high, suggesting that the feature extraction method based on principal component analysis (PCA) is effective. In addition, compared with conventional similarity calculation methods of cosine angle and correlation coefficient, the new similarity calculation method achieves better classification results and better generalization ability. This work provides a method of quantitative analysis and rapid identification of PCE for the construction site.

We propose a novel design of photonic crystal fiber to achieve the single-polarization single-mode transmission. The topology of this design only employs, with a view of simplicity and stability, uniformly sized circular air holes, and they are all regularly latticed in a pure-silica background. Guiding properties are studied by use of the full-vector finite element method, combined with perfectly matched layers as absorbing boundary conditions. It has been found that, increasing the hole-to-pitch ratio can be performed to broaden the SPSM band, however, subject to a qualification that the ratio should be inadequate to open a bandgap. In addition, influences of the ring number and the inner cladding coverage on transmission characteristics have been thoroughly investigated. An optimized sample is deliberately designed to offer an SPSM band with width of 120 nm, centered at \\boldsymbol $\lambda = $ 1.55 μm. Moreover, the proposed design demonstrates low confinement loss, high nonlinear coefficient, as well as excellent bending resistance.

Sodium-ion hybrid capacitors (SICs) are attracting increasing attention due to their high energy/power superiority and potentially low cost. However, the sluggish sodium-ion diffusion in the bulk o...

With the development of modern engineering technology, the development of high-performance and multifunctional polymer materials has been promoted. In this work, a novel nanohybrid based on chitosan engraved zinc and iron mixed oxyhydroxide at the presence of halloysite nanotubes (HNTs) as the carrier, followed by surface capping with stearic acid to obtain super-hydrophobic HNT@CSZFMOH nanofiller. The as-obtained HNT@CSZFMOH nanofiller was incorporated into epoxy resin (EP) matrix. With the addition of 3 wt.% HNT@CSZFMOH, the peak heat release rate and peak smoke production of the EP nanocomposite decreased by 35% and 32%, respectively. This excellent flame retardancy is attributed to that the enhanced physical barrier derived from HNT@CSZFMOH, and the dense, highly graphitized char layer formed by catalytic charring of ultrafine FeOOH and ZnOOH nanoparticles. Meanwhile, the nanohybrid imparted outstanding hydrophobicity to the hydrophilic substrate EP with the water contact angle (CA) of 159°. EP-matrix nanocomposite exhibited desired self-cleaning performance as well as good resistance against corrosive liquids (acid and alkaline solutions) and ultraviolet irradiation. The present approach, with simple procedures and desired environmental acceptance, could provide feasible pathway to fabricating multifunctional polymer–matrix composites.

Silicon-based materials, as the most promising candidates for high-performance lithium-ion batteries (LIBs), have been widely researched. However, the construction of stable electrode structure is still a challenge due to the enormous volume variation. Herein, we developed a three-dimensional (3D) binder network, polydopamine grafted cross-linked polyacrylamide (PDA-c-PAM), to build a durable anode for LIBs. The flexible PDA side chain in PDA-c-PAM offers the superior adhesion with constitutes of the electrode. And the 3D cross-linked PAM main chain endows PDA-c-PAM high stretchability to accommodate the volume variation of active material and maintain the structural integrity of electrode. As a binder for SiO/graphite (SiO/C), the fabricated SiO/C@PDA-c-PAM anode delivers an initial discharge capacity of 1350 mAh g−1 at 0.1 A g−1. At a high current density of 1 A g−1, it maintains 591 mAh g−1 after 300 cycles with a 94% capacity retention of initial capacity after activation. Coupled with commercial LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode, the full cell exhibits a high-energy density of 406 Wh kg−1 at 1 C as well as excellent stability. Thus, it is believed that designing 3D network binder is an effective approach to achieve superior cycle performance of SiO/C electrodes. We successfully synthesized a polydopamine grafted cross-linked polyacrylamide (PDA-c-PAM) polymer as binder for SiO/C anode to maintain the structural integrity and improve the cycling stability of electrode. The flexible PDA side chain in PDA-c-PAM offers the binder superior adhesion. And the 3D cross-linked PAM main chain endows the binder high stretchability. The fabricated SiO/C@PDA-c-PAM anode delivers a capacity of 591 mAh g−1 after 300 cycles at 1 A g−1. Thus, it is believed that designing 3D network binder is an effective approach to achieve superior cycle performance of SiO/C electrodes.

International audience; Over the last three decades, photonic crystals (PhCs) have attracted intense interests thanks to their broad potential applications in optics and photonics. Generally, these structures can be fabricated via either ‘‘top-down’’ lithographic or ‘‘bottom-up’’ self-assembly approaches. The self-assembly approaches have attracted particular attention due to their low cost, simple fabrication processes, relative convenience of scaling up, and the ease of creating complex structures with nanometer precision. The self-assembled colloidal crystals (CCs), which are good candidates for PhCs, have offered unprecedented opportunities for photonics, optics, optoelectronics, sensing, energy harvesting, environmental remediation, pigments, and many other applications. The creation of high-quality CCs and their mass fabrication over large areas are the critical limiting factors for real-world applications. This paper reviews the state-of-the-art techniques in the self-assembly of colloidal particles for the fabrication of large-area high-quality CCs and CCs with unique symmetries. The first part of this review summarizes the types of defects commonly encountered in the fabrication process and their effects on the optical properties of the resultant CCs. Next, the mechanisms of the formation of cracks/defects are discussed, and a range of versatile fabrication methods to create large-area crack/defect-free twodimensional and three-dimensional CCs are described. Meanwhile, we also shed light on both the advantages and limitations of these advanced approaches developed to fabricate high-quality CCs. The self-assembly routes and achievements in the fabrication of CCs with the ability to open a complete photonic bandgap, such as cubic diamond and pyrochlore structure CCs, are discussed as well. Then emerging applications of large-area high-quality CCs and unique photonic structures enabled by the advanced self-assembly methods are illustrated. At the end of this review, we outlook the future approaches in the fabrication of perfect CCs and highlight their novel real-world applications.

Mesocrystals have received intense attention in the electrochemical energy storage field owing to their favourable electronic conductivity, high crystallinity and large specific surface area. However, a critical limitation to the wide applications of mesocrystals is the lack of a facile synthesis approach for high-performance mesocrystals. Here, we report a one-step self-assembly solvothermal method to prepare 3D hierarchical highly-ordered Nb3O7F nanowire cluster mesocrystals (denoted NOF-NCMs), of which the diameter of each nanowire is within 10 nm. Through kinetic analysis, NOF-NCMs can be confirmed to provide unique intercalation pseudocapacitance, enabling rapid charge transfer. When used as an anode material, the NOF-NCM electrode displays a high capacity of ∼356.7 mAh g−1 at 800 mA g−1, excellent rate performance and a long cycle life with ∼88.3% capacity retention after 3000 cycles. The improved electrochemical properties of NOF-NCMs are attributed to the unique highly-ordered nanowire cluster architectures. A lithium ion capacitor (LIC) is constructed by using well-prepared NOF-NCMs as an anode and commercial AC as a cathode. The NOF-NCMs//AC LIC can hold a maximum energy density of 74.5 W h kg−1 at 87.5 W kg−1, and has a long cycle lifespan with a 92.5% capacity retention after 3000 cycles and low self-discharge rate, demonstrating a bright candidate for applications in both high-energy and high-power electrochemical energy storage.

Nickel-rich layered oxides with excellent specific capacity and reasonable cost have extensively employed as cathode materials for higher energy density lithium-ion batteries (LIBs). However, side ...

In the present work, Titanium dioxide (TiO2) micro–nanostructured thin films are deposited by a cold atmospheric plasma jet on carbon fiber substrates. The surface morphology, grain size, and structure phase of TiO2 thin films are investigated by scanning electron microscopic (SEM), X-ray diffraction (XRD), and Raman spectrum. As the discharge voltage increased from 5 to 15 kV, the size of these TiO2 particles decreased from 2 to 3 μm to less than 1 μm. The XRD and Raman spectroscopic results show TiO2 on the carbon fiber surface prepared by atmospheric plasma jet is at the mixture phase of anatase and rutile. We also investigated the adhesion and proliferation assays of MC3T3-E1 preosteoblasts on the samples. The surface with smaller TiO2 particles deposited on carbon fiber is more appropriate for attachment of preosteoblasts. Furthermore, the highest proliferation of MC3T3-E1 was found on a sample with smaller TiO2 particles after incubation. Our data suggest that the increased roughness fosters cell attachment and proliferation on the surface of TiO2/carbon fibers.

Lithium–sulfur (Li–S) batteries have been considered as one of the most promising next-generation rechargeable battery technologies owing to the high theoretical energy density and the low cost of ...

Thermionic electron sources are scaled down to the microscale on a chip and batch fabricated on 4-in silicon wafers by utilizing microfabrication technologies and exploiting carbon nanotubes as microscopic filaments of thermionic electron emission. The microfabricated on-chip thermionic electron sources not only satisfy the metrics of compactness and ease of batch fabrication, but also exhibit the advantages of good performance reproducibility (±6.9% variation over 100 test cycles under a driven voltage of 3.5 V) and high emission stability (fluctuation < 5% for emission current level of ≈10−8 A over 900 s) under a relatively low vacuum condition (10−4–10−2 Pa). Furthermore, to extract electrons and tune emission current, an extraction gate with a mesh is monolithically integrated with the thermionic electron sources using anodic bonding technique. The integrated electron sources exhibit a strong gate controllability and a considerable electron transmission ratio of ≈76% through the extraction gate. All these results make our devices a promising type of on-chip electron source in the applications of miniature vacuum electronic devices/systems.

Electron emission (EE) from electron sources based on island metal films (IMFs) was mainly attributed to field emission or thermionic emission from IMFs. Here, we propose a new mechanism of EE from IMF-based sources, namely, EE from horizontal tunneling junctions formed in the substrate. The devices with and without IMFs fabricated on silicon oxide substrates are found to exhibit similar EE properties, while the island-metal-film-based devices fabricated on Si3N4/Si substrate show no EE. The comparative results indicate that EE originates from the underlying silicon oxide substrate that was ignored in previous mechanisms, but not from IMFs. EE from the devices is thought to be generated from horizontal tunneling junctions in electroformed silicon oxide substrate due to the rupture of conducting filaments. Even though metal island films are not the origin of EE, they can greatly decrease the forming voltage of the devices. The insights into the emission mechanism are helpful for optimizing the electron source performances.

We report the unconventional space-free confined growth of Au nanoshells with well-defined plasmonic properties and active tuning of their plasmon coupling by the nanoscale magnetic assembly. The seeded growth of Au exclusively occurred at the hard-soft interfaces between the Fe3O4 core and phenolic resin without the need of creating a limiting space, which represents a general and elegant approach to various core-shell nanostructures. The deformability of permeable phenolic layers plays an essential role in regulating the interfacial growth of Au nanoshells. While the polymer elasticity suppresses the radial deposition of Au atoms, their high deformability can afford enough spaces for the formation of conformal metallic shells. The coupled magnetic-plasmonic properties allow active tuning of the plasmon coupling and the resonant scattering of Au nanoshells by the magnetic assembly of the hybrid nanoparticles into plasmonic chains, whose potentials in applications have been demonstrated in designing transparent displays and anticounterfeiting devices.

Zinc ion hybrid supercapacitors (ZISCs), as one of emerging energy storage devices, have gained numerous attentions due to their high safety, satisfied energy/power output, low-cost and long-term durability. To construct a satisfying ZISC with good charge storage behavior, well-developed electrode structures and optimized electrolytes by effective strategies are highly demanded. However, current basic research is relatively far from its practical application, which has greatly deferred the large-scale production of ZISC and has become a key issue. Here, recent advances towards the ZISCs have been systematically summarized to meet such challenges, with a focus on the charge storage mechanism. In addition, insights into the development of electrodes and electrolytes are presented. It is worth believing that this review could be a medium for attracting more efforts to the early rise of ZISCs in terms of the sustainable material preparations and the advanced technique inventions.

In order to enhance the flame retardancy of intumescent flame retardant (IFR) in polypropylene (PP) using synergistic effects, a three-dimensional flower-like nickel cobaltate (NiCo2O4) was prepared and first introduced into the PP/IFR composite. The combustion behavior, thermal stability, mechanical properties and hydrophobicity of PP/IFR containing NiCo2O4 are studied in detail. When the contents of NiCo2O4 and IFR are 1.5 wt% and 18.5 wt%, respectively, the limit oxygen index value of the PP composite reaches 34.5 and passes the UL-94V-0 level. The cone calorimetry test also reveals that NiCo2O4 plays an excellent synergistic role with IFR, resulting in a significant improvement in the flame retardancy of the PP composite. Compared with pure PP, the presence of 1.5 wt% of NiCo2O4 delays combustion, decreases the peak heat release rate and total heat release by 64% and 40%, respectively, as well as exhibits a significant smoke suppression effect. At high temperature, the residual char of the PP composite is increased, and the degree of graphitization of corresponding char is also improved, both of which contribute to forming a continuous dense stable char layer and acquire a better shielding effect. The presence of NiCo2O4 only has a slight negative effect on the tensile strength of the PP composite. Interestingly, the hydrophobicity of the PP composite at this ratio is improved to some extent compared with that of the composite containing only 20 wt% IFR; thus, the synergistic flame-retardant effect is also ensured in the water resistance test within a certain time.

Developing lithium ion capacitors (LICs) with high energy density is still challenging, due to the kinetic mismatch between the capacitor-type cathode and the battery-type anode. In addition, metal-free LICs are preferred over high-cost and unsustainable metal-containing electrode materials. Exploring appropriate metal-free cathode and anode materials with high capacity and excellent rate performance is one of the keys to attain such goal. Herein, nanoarchitectured graphene-based LICs are successfully constructed by using 2D polydopamine-graphene heterostructured anode and porous graphene cathode. The 2D nature of polydopamine-graphene facilitate the transport of electrolyte ions while graphene promotes electron transfer. The high specific surface area of the porous graphene endows ions with accessibility and fast transport. The metal-free LIC device achieves a high energy density (135.6 Wh kg−1 at 210.4 W kg−1), high power density (21.0 kW kg−1 at 78.9 Wh kg−1), high low-temperature performance (76.4 Wh kg−1 at −20 °C), and reasonably long cycling life. This work provides an effective strategy to design metal-free LIC with high performance at wide temperature range.

Although interlayer binding energy (IBE) is a key parameter relevant to the electronic properties and device performances of hexagonal MoS2, a promising two-dimensional (2D) semiconductor, it has n...

The ability to restrict the shuttle of lithium polysulfide (LiPSn) and improve the utilization efficiency of sulfur represents an important endeavor toward practical application of lithium–sulfur (...

In this paper, the Al-doped C2N monolayers (Al-C2N and Al2-C2N) are proposed as a new type of gas adsorbent for air pollution. Based on first-principle calculations, the adsorption properties of Al...

Metallic lithium is regarded as the “Holy Grail” among various anode materials for the next-generation rechargeable batteries. Unfortunately, the inhomogeneous Li deposition and uncontrolled dendrite growth during repeated cycling lead to low Coulombic efficiency, poor performance, and serious safety issues. Herein, a novel two-pronged strategy is proposed to effectively guide Li nucleation and suppress the unwanted Li dendrites growth, by a synergized approach of combining the laser-machined 3D holey Cu matrix (3D Cu) and lithiophilic polydopamine (PDA) surface coating layer. The PDA@3D Cu scaffold is shown to exhibit the wanted dendrite-free Li plating/stripping behavior. It delivers a remarkable Coulombic efficiency of 96.4% after 150 cycles (2.0 ​mA ​cm−2 ​at 1.0 mAh cm−2), and achieves an excellent lifespan of over 1000 ​h operation tested in Li/Li symmetric cells, together with good stability for Li//FePO4 full batteries. Our molecular dynamics (MD) simulations, density functional theory (DFT) calculations, and in-situ real-time monitoring using optical microscopy together have established the direct correlation between reversible Li electrodeposition and lithiophilic 3D holey structure scaffold. Significantly, the new findings suggest that a synergistic combination of 3D Cu with lithiophilic PDA coating layer represents an effective pathway to regulate metallic Li anodes towards practical applications.

Lithium-ion capacitors (LICs) are gradually emerging as one of the most indispensable hybrid energy storage devices. However, it is one main challenge to evade the mismatch of electrochemical kinetics and specific capacity between cathode and anode in LICs. Herein, we have proposed an efficient strategy to prepare the nitrogen-doped hierarchical porous carbon spheres (NHPCS) as cathode, which is synthesized by a simple aerosol-spraying pyrolysis using the low-cost phenolic resin as carbon source without any other catalyst or hard template. The NHPCS exhibits porous nanospheres structure with an appropriate nitrogen doping level (3.65 at.%). Benefitting from the two-pronged strategy of N-doped feature and nanostructure engineering, NHPCS achieves a high specific capacity of 74 mAh g−1 at a current density of 0.1 A g−1 and remains 86.5% of initial capacity even being subjected to a high rate of 50-fold. Furthermore, a high-performance LIC has been developed by coupling NHPCS cathode and hard carbon anode, which delivers a maximum energy density of 151 Wh kg−1 and excellent cycle stability (96.3% capacity retention after 3000 cycles). Significantly, such designed porous carbon could not only be convenient for scalable production, but also be served for many other energy storage devices. We have presented a larger-scale spray pyrolysis strategy to prepare nitrogen-doped hierarchical porous carbon spheres (NHPCS). A high-stable lithium-ion capacitor has been constructed by coupling NHPCS cathode with hard carbon anode, which exhibits a maximum energy density of 151 Wh kg−1 and capacity retention of 96.3% over 3000 cycles, showing great potential for the next-generation energy storage application.

Mechanochromic response is of great importance in designing bionic robot systems and colorimetric devices. Unfortunately, compared to mimicking motions of natural creatures, fabricating mechanochromic systems with programmable colorimetric responses remains challenging. Herein, we report the development of unconventional mechanochromic films based on hybrid nanorods integrated with magnetic and plasmonic anisotropy. Magnetic-plasmonic hybrid nanorods have been synthesized through a unique space-confined seed-mediated process, which represents an open platform for preparing next-generation complex nanostructures. By coupling magnetic and plasmonic anisotropy, the plasmonic excitation of the hybrid nanorods could be collectively regulated using magnetic fields. It facilitates convenient incorporation of the hybrid nanorods into polymer films with a well-controlled orientation and enables sensitive colorimetric changes in response to linear and angular motions. The combination of unique synthesis and convenient magnetic alignment provides an advanced approach for designing programmable mechanochromic devices with the desired precision, flexibility, and scalability., Programmable mechanochromic systems hold important roles in designing advanced bionic robots and colorimetric devices. Herein, the authors report the development of magnetic-plasmonic hybrid nanorods that can be integrated into thin polymer films with controlled orientations to display programmable mechanochromism.

Aqueous zinc-ion batteries have been widely reported as promising candidates for energy storage, but the research on zinc-ion based supercapacitors or hybrid supercapacitors has received little attention and the energy storage mechanism is still controversial. Here, a high-performance zinc-ion hybrid supercapacitor is successfully demonstrated with biowaste-derived porous carbon and cheap zinc foil. Thanks to the bivalent characteristic of zinc and electric double layer capacitive nature of porous carbon, as-assembed hybrid supercapacitors can achieve high energy density of 147.0 ​Wh kg−1 at 136.1 ​W ​kg−1 and a maximum power density of 15.7 ​kW ​kg−1 at 65.4 ​Wh kg−1 together with outstanding cycling stability (92.2% capacity retention after 10000 cycles at a high current density of 10 ​A ​g−1). Most importantly, 61.6% of the initial capacity at 1 ​A ​g−1 can be remained even under a mass loading as high as 17 ​mg ​cm−2. Significantly, the phase composition of byproducts formed in Zn(CF3SO3)2 electrolyte have been confirmed by ex-situ experimental results and theoretical calculations. Besides, when appling optimized carbon cathode into quasi-solid-state hybrid supercapacitors with a unique anti-freezing hydrogel electrolyte, this device can well service at various bending states and relatively low temperature of −15 ​°C.

The electron density distribution and average electron temperature distribution in reactive ion etching (RIE) chamber are of great significance for the ionization and excitation reaction rate. The uniformity of radial distributions of the electron density and average electron temperature in the discharge chamber greatly affects the uniformity of the etching, especially the plasma etching of large area SiO2 substrates. We study the effects of discharge conditions (including power and pressure) on the electron density and average electron temperature of plasma-etched 400 mm SiO2 substrates in the reactive ion etching chamber; the simulation results show that the allowable major discharge conditions strongly affect the characteristics of plasma in the large area reactive ion etching chamber. Specifically, with increase in the power both the electron density and average electron temperature increase, being accompanied by deteriorating uniformity of their radial distributions. As the pressure increases, the electron density increases but average electron temperature decreases, being accompanied by deteriorating uniformity of their radial distributions. These methods and conclusions can provide reference for the improvement of cavity structure and large area RIE equipment designing and selection of the process parameters.

Lithium-ion capacitors (LICs) are regarded as the most potential devices in the energy storage systems. Unfortunately, the mismatched in the intrinsic kinetics and specific capacities between anode and cathode lead to a depressed electrochemical performance. Thus, designing an advanced electrode material that combines high performance with low-cost is one of the main challenges for LICs, especially in a sustainable anode material until now. Here, a high-energy LIC has been successfully developed using the defect-rich and N-doped hard carbon (DNC) as anode, which is prepared through the carbonization process of the low-cost biowaste sepia without additional template or catalyst. The DNC shows nanospherical structure with a diameter of about 100 nm. Owing to the two-pronged strategy of N-doping and defect engineering, it delivers a high specific capacity (580.3 mAh g−1 at 0.05 A g−1), excellent rate capability, and long cycle stability (1000 cycles). The electrochemical kinetic analysis and density functional theory (DFT) calculations have confirmed its prominent pseudocapacitive behaviors and excellent Li+ storage capability. As expected, the as-fabricated LIC delivers a remarkable energy density (101.7 Wh kg−1), an outstanding rate capability (56.3 Wh kg−1 at 12.5 kW kg−1), and a superior cycle lifespan (3000 cycles), demonstrating the tremendous potential for the next-generation energy storage systems.

Hydrogen energy is a highly efficient and renewable energy carrier. The rapid and sophisticated development of nanotechnologies has promoted the transition of hydrogen storage systems from gaseous/liquid to solid-state. In order to clarify the intrinsic relationship between structure and performance, and to understand the hydrogen absorption and desorption mechanism of materials, electron microscopy (EM) can effectively help us obtain a series of information such as particle size, phase and composition determination, morphology and structure of the materials at nanoscale. The most recent progress of advanced EM techniques applied in solid-state hydrogen storage materials are summarized, which should also inspire future research on energy storage related materials.

For a potential and efficient solution in the mitigation of aquatic pollution, this study reported a well-designed and developed protected granulated activated carbon (GAC) material which ensures high strength property and adsorption performance to meet the industrial application. The prepared GAC material was shaped into a spherical core using natural binders basically assumed to constitute waste solids materials. Then after, the granulated carbon core (GAC core) was protected by a porous ceramic shell which confined the material with strong protection and high mechanical strength to resist against degeneration and pressure drop as a limiting factor for most sorbents employed in solution. The CSGAC characterization results proved that the ceramic shell has a smaller thickness (0.1 cm), good mechanical strength (2.0 MPa), and additionally, it presents larger porous channels which promote the fast and higher adsorption performance making it the desired material for the application in the real liquid environment. The test results showed that the prepared material had higher removal of triclosan (TCS) (30-40 mg/L) than BPA counterpart from the aqueous solutions. Moreover, it showed higher adsorption performance compared to the unprotected carbon materials. Furthermore, the mechanisms of BPA and TCS adsorption by core-shell granulated activated carbon (CSGAC) were discussed.

We report a remarkable thickness-dependent wrinkling behavior of oxygen plasma-treated polydimethylsiloxane (PDMS) films, in which an energy barrier separates the wrinkling mechanics into two regimes. For thick films, the film wrinkles with a constant periodicity which can be precisely predicted by the classic nonlinear finite mechanics. Reducing the film thickness below 1 mm leads to nonuniform wrinkles with an increasing periodicity which gives rise to random scattering and transparency changes under mechanical strains. By tuning the film thickness, we were able to control both the quality and size of the periodic wrinkles and further design mechanochromic devices featuring brilliant structural colors and programmable colorimetric responses. This work sheds light on the fundamental understanding of the wrinkling mechanics of bilayer systems and their intriguing mechanochromic applications.

Solution-processed semiconductor nanowires are attractive for application in low-cost and high-performance electronic devices. However, current approaches for nanowire preparation face the problems of having low-throughput and poor controllability of the dimension and location of nanowires. Here we report a simple yet efficient method to implement solution-processable semiconductor nanowires using microfluidics. The method enables fabrication of semiconductor nanowires with high uniformity and well-defined sizes, as well as precise control of their location and alignment in device assembly. Moreover, this method is found to be applicable to various semiconductors, including organic semiconductors (OSCs) and metal-halide perovskites. Furthermore, we have shown the feasibility of employing these semiconductor nanowires to construct different types of devices like field-effect transistors (FETs) and photodetectors (PDs). In particular, lateral heterojunctions consisting of perovskite/OSC nanowires were obtained by this method, based on which high-performance phototransistors were achieved. Overall, the demonstrated method provides a promising route to the fabrication and application of nanowire-based devices.