Sponge‐Templated Preparation of High Surface Area Graphene with Ultrahigh Capacitive Deionization Performance

Capacitive deionization (CDI) is a competent water desalination technique offering an appropriate route to obtain clean water. However, a rational designed structure of the electrode materials is essentially required for achieving high CDI performance. Here, a novel sponge‐templated strategy is developed for the first time to prepare graphene sheets with high specific surface area and suitable pore size distribution. Sponge is used as the support of graphene oxide to prevent the restack of graphene sheets, as well as to suppress the agglomerate during the annealing process. Importantly, the as‐fabricated graphene sheets possess high specific surface area of 305 m² g^?1 and wide pore size distribution. Ultrahigh CDI performance, a remarkable electrosorptive capacity of 4.95 mg g^?1, and siginificant desorption rate of 25 min, is achieved with the sponge‐templated prepared graphene electrodes. This work provides an effective solution for the synthesis of rational graphene architectures for general applications in CDI, energy storage and conversion.     

萝藦壳衍生多孔碳电极及其在电容去离子中的应用

选用常见的生物质萝藦壳作为碳源,并采用水热碳化法和化学活化法,通过K2CO3和KOH进行活化后,分别得到多孔碳材料并命名为MPJ-KCO和MPJ-KO,与不使用活化剂的样品MPJ-CB进行对比,MPJ-KO具有丰富的微孔和介孔,且比表面积达到1586 m2/g。在扫描速率5 mV/s下,MPJ-KO电极比电容达149.9 F/g。在电容去离子(CDI)脱盐实验中,MPJ-KO电极脱盐量达到16.20 mg/g。通过这项研究,不仅可以最大化废弃生物质的价值,还提供了其在CDI脱盐中的潜在应用。     

Rapid Inversion of Surface Charges in Heteroatom‐Doped Porous Carbon: A Route to Robust Electrochemical Desalination

Given that a considerably large population suffers from shortage of water, there are numerous on‐going efforts to turn seawater into freshwater, and electrochemical desalination processes—particularly capacitive deionization (CDI)—have gained significant attention due to their high energy efficiency and reliable performance. Meanwhile, carbonaceous electrode materials, which are most commonly used in CDI systems, have poor long‐term stability due to unfavorable interactions with oxygen in saline water. Herein, rapid and vigorous inversion of surface charges in heteroatom‐doped carbon electrodes, which leads to a robust operation of CDI with high desalination capacity, is reported for the first time. By carbonization of coffee wastes, nitrogen‐ and sulfur‐codoped activated carbon with hierarchical micro/mesopores are prepared in an environmentally‐friendly manner, and this carbon results in a significantly higher inverted capacity than that of various activated carbon counterparts in long‐term CDI operations, without any sign of drop in performance. Investigations on the changes in physicochemical properties of the electrodes during the inversion disclose the favorable roles of nitrogen and sulfur dopants, which can be summarized as enlarging the difference between the surface charges of the two electrodes by chemical interactions with oxygen in the anode and carbon in the cathode.     

Nanoarchitectured Design of Vertical-Standing Arrays for Supercapacitors: Progress,Challenges, and Perspectives

Vertical-standing arrays have aroused great enthusiasm as electrode materials for supercapacitors in recent years owing to their structural and compositional characteristics. Although significant efforts have been made in the construction of vertical-standing arrays with tailored compositions and architectures, an in-depth understanding of the relevant structure–activity relationships has not yet been reviewed in detail. Herein, recent important progress in controllably synthesizing vertical-standing arrays as well as their application as supercapacitors is reviewed. Afterward, promising strategies to improve the electrochemical performance of vertical-standing arrays are discussed. Finally, the challenges and possible directions for developing vertical-standing arrays with outstanding performance are outlined. This review provides important guidelines for designing and regulating vertical-standing arrays and constructing desirable electrode materials for future electrochemical energy storage.     

Nanoneedle Platforms: The Many Ways to Pierce the Cell Membrane

Establishing techniques to efficiently and nondestructively access the intracellular milieu is essential for many biomedical and scientific applications, ranging from drug delivery, to electrical recording, to biochemical detection. Cell penetration using nanoneedle arrays is currently a research focus area because it not only meets the increasing therapeutic demands of cell modifications and genome editing, but also provides an ideal platform for tracking long‐term intracellular information. Although the precise mechanism driving membrane penetration by nanoneedle arrays is still unclear, the low cytotoxicity, wide range of delivered materials, diverse cell type targets, and simple material structures of nanoneedle arrays make these splendid platforms for cell access. Here, the recent progress in this field is reviewed by examining device architectures and discussing mechanisms for nanoneedle penetration, and the major studies demonstrating the most general applicability of nanoneedle arrays, typical methodologies to access the intracellular environment using nanoneedles with spontaneous or assisted penetration modes, as well as biosafety aspects are presented. This review should be valuable for deeply understanding the materials fabrication principles, device designs, cell penetration methodologies, biosafety aspects, and application strategies of nanoneedle array‐based systems that are of crucial importance for the development of future practical biomedical platforms.     

Divalent Ion Selectivity in Capacitive Deionization with Vanadium Hexacyanoferrate: Experiments and Quantum-Chemical Computations

Selective removal of ions from water via capacitive deionization (CDI) is relevant for environmental and industrial applications like water purification, softening, and resource recovery. Prussian blue analogs (PBAs) are proposed as an electrode material for selectively removing cations from water, based on their size. So far, PBAs used in CDI are selective toward monovalent ions. Here, vanadium hexacyanoferrate (VHCF), a PBA, is introduced as a new electrode material in a hybrid CDI setup to selectively remove divalent cations from water. These electrodes prefer divalent Ca²⁺ over monovalent Na⁺, with a separation factor, β_Ca/Na ≈3.5. This finding contrasts with the observed monovalent ion selectivity by PBA electrodes. This opposite behavior is understood by density functional theory simulations. Furthermore, coating the VHCF electrodes with a conducting polymer (poly-pyrrole, doped with poly-styrenesulphonate) prevents the contamination of the treated water following the degradation of the electrode. This facile and modular coating method can be effortlessly extended to other PBA electrodes, limiting the extent of treated water contamination during repeated cycling. This study paves the way for tunable selectivity while extending the library of electrodes that can be successfully used in (selective) CDI.     

Aquaporin-Based Biomimetic Membranes for Low Energy Water Desalination and Separation Applications

The emergence of biomimetic materials developed using nature's inspiration and biological domains can drive a paradigm shift in the design and operation of future-generation materials in separation applications. In recent years, biomimetic membranes have drawn interest of many researchers for water treatment applications. Among the biomimetic membranes, protein-based membranes, specifically those synthesized by aquaporin, have received much attention in recent years due to their high osmotic water permeability and excellent ability to remove small molecules, thereby overcoming the trade-off between the water flux and the contaminant's rejection. The separation efficiency and fouling properties are significantly improved by taking advantage of the strategies evolved in nature. This review provides a comprehensive overview of the state-of-the-art aquaporin-based biomimetic membranes (ABMs), mainly focusing on their synthesis, characterization, and performance as selective layer in composite membranes for reverse osmosis, nanofiltration, and forward osmosis for water desalination. Fabrication methods and characterization techniques of ABMs and their performance in water desalination are also reviewed, while the main obstacles for their successful commercial viability in wastewater treatment are provided. The applications of ABMs in various separation processes other than water desalination and their potential market are presented to inspire future researchers in this versatile area.     

Recent Progress in Synthesis and Application of Biomass-Based Hybrid Electrodes for Rechargeable Batteries

The rapid growth in electronic and portable devices demands safe, durable, light weight, low cost, high energy, and power density electrode materials for rechargeable batteries. In this context, biomass-based materials and their hybrids are extensively used for energy generation research, which is primarily due to their properties such as large specific surface area, fast ion/electron kinetics, restricted volume expansion, and restrained shuttle effect. In this review, the key advancements in the preparation of biomass derived porous carbons using different synthesis strategies and their modifications with species such as heteroatoms, metal oxides, metal sulfides, silicon, and other carbon forms are discussed. The electrochemical performances of these materials and the ion storage mechanisms in different batteries including lithium-ion, lithium–sulfur, sodium-ion, and potassium-ion batteries are discussed. Special attention will be paid to the challenges in using porous biomass-derived carbons and the current strategies employed for maximizing the specific capacity and lifetime for battery applications. Finally, the drawbacks in current technology and endeavors for the future research and development in the field to catapult the performances of the biomass derived materials in order to equip them to meet the demands of commercialization are highlighted.     

循环经济模式下的海水淡化前景

循环经济的核心是资源节约及再利用,在电厂及钢厂项目中设置的海水淡化装置则是充分利用本来会排放的无法利用的低压余热。介绍河北曹妃甸工业区作为国家级循环经济示范区在北疆电厂项目中采取循环经济形式,开展浓盐水综合利用的标准示范工程中,其大大降低海水淡化后的成品水成本,并且避免了对我国近海环境的影响。海水淡化以及海水的循环利用必然是未来我国北方城市获得高质量水资源的可靠及有效的途径。     

智能终端系统安全性研究

对智能终端所面临的安全威胁及安全需求进行了研究,分析比较了当前主流智能终端操作系统的安全特性、架构和机制,并针对现有安全问题及机制提出了安全增强方法,最后对智能终端系统未来发展趋势进行了预测分析。     

Engineered Polymeric Carbon Nitride Additive for Energy Storage Materials: A Review

The ever-increasing demands for high energy density electronics have motivated research on exploring new types of electrode materials featuring mechanical flexibility and electrical storage capability. Of these, polymeric carbon nitride (PCN) has been increasingly studied in regard to electrical energy storage (EES) because of its abundant pyridinic N content, which is beneficial for enhancing electrochemical performance. However, state-of-the-art PCN-based electrode materials for EES are still far from industrial requirements. Herein, the current status of PCN-based materials in batteries and supercapacitors (SCs) is primarily discussed. A particular emphasis is placed on the PCN processing into composite electrode materials, including the defect engineering of pristine PCN and its coupling with other conductive materials to develop heterojunction nanostructures, which is essential for developing highly efficient electrode materials. Moreover, the direct pyrolysis of PCN into N-doped graphene with a tunable N content is introduced and achieves remarkable energy storage performance with superior electronic conductivity. Furthermore, the energy storage mechanisms for batteries and SCs are also highlighted to reveal structure–performance relationship. Finally, this comprehensive review outlines the remaining challenges and strategies for future improvements in PCN-based materials in this emerging field. This review will provide inspiration on developing future PCN-based materials for EES.     

Battery Electrode Materials with Omnivalent Cation Storage for Fast and Charge‐Efficient Ion Removal of Asymmetric Capacitive Deionization

Capacitive deionization (CDI) that engages porous carbon electrodes constitutes one of the well‐established energy‐efficient desalination methods. However, improvement in desalination performance, including ion removal capacity, ion removal rate, and charge efficiency remains requisite for a wide range of applications. Herein, an ion‐exchange membrane‐free asymmetric CDI is introduced by pairing a metal organic framework (MOF), namely, K_0.03Cu[Fe(CN)₆]_0.65·0.43H₂O and porous carbon. The exclusive intercalation of cations into the MOF prevents the reverse adsorption of co‐ions (anions), thus significantly improving ion removal capacity (23.2 mg g^?1) and charge efficiency (75.8%). Moreover, by utilizing the advantage of the MOF that diverse mono‐ and divalent cations can be stored in the narrow redox potential range, the asymmetric CDI allows simultaneous capture of mono‐ and divalent cations, thus achieving omnivalent cation removal. Moreover, cations are intercalated in the hydrated forms without a discrete phase transition of the host structure, facilitating rapid desalination by reducing the desolvation energy penalty, which results in a high ion removal rate of 0.24 mg g^?1 s^?1. This study offers a new design principle in CDI: the integration of a crystal structure with large ionic channels that enable hydrated intercalation of multivalent ions in a fast and exclusive manner.     

Security in Internet of Things: issues,challenges, taxonomy,and architecture

Internet technology is very pervasive today. The number of devices connected to the Internet, those with a digital identity, is increasing day by day. With the developments in the technology, Internet of Things (IoT) become important part of human life. However, it is not well defined and secure. Now, various security issues are considered as major problem for a full-fledged IoT environment. There exists a lot of security challenges with the proposed architectures and the technologies which make the backbone of the Internet of Things. Some efficient and promising security mechanisms have been developed to secure the IoT environment, however, there is a lot to do. The challenges are ever increasing and the solutions have to be ever improving. Therefore, aim of this paper is to discuss the history, background, statistics of IoT and security based analysis of IoT architecture. In addition, we will provide taxonomy of security challenges in IoT environment and taxonomy of various defense mechanisms. We conclude our paper discussing various research challenges that still exist in the literature, which provides better understanding of the problem, current solution space, and future research directions to defend IoT against different attacks.     

Lithium-Ion and Sodium-Ion Hybrid Capacitors: From Insertion-Type Materials Design to Devices Construction

There is a great appeal to develop an omnipotent player combining lithium-ion batteries (LIBs) with the capacitive storage communities. Hybrid capacitors as a kind of promising energy storage device are attracting increasing attention in the main playground in recent years. Unlike supercapacitors (SCs) and LIBs, hybrid capacitors combine a capacitive electrode with a Faradaic battery electrode. In these hybrid cells, the capacitive electrode brings the power while the energy mainly comes from the Faradaic one. Numerous efforts have been conducted in the past decades; however, the research about hybrid capacitors is still at its infancy stage, and it is not expected to replace LIBs or SCs in the near future utterly. Here, the advances of hybrid capacitors, including insertion-type materials, lithium-ion capacitors, and sodium-ion capacitors, are reviewed. This review aims to offer useful guidance for the design of faradic battery electrodes and hybrid cell construction. Brief challenges and opportunities for future research on hybrid capacitors are finally presented.     

Characterization and comparison of single and stacked MIMC in copper interconnect Process for mixed-mode and RF applications

This letter presents the dc and RF study and comparison on four manufacturable single- (one and dual additional masks) and stacked- (intraand multiple inter-) metal-insulator-metal capacitors (MIMCs) in a Cu dual-damascene backend of line process. The capacitors were found to exhibit low leakage and high breakdown field strength, absence of dispersive behavior, and good voltage and temperature linearity. Their quality factor (Q) values are different due to the different electrode series resistance as a result of different architectures. The stacked MIMC offers reduced chip area for the same capacitance value and is a viable manufacturable alternative for current and future precision mixed-mode capacitor incorporating SiN or high-/spl kappa/ dielectric materials.     

Anionic Redox in Rechargeable Batteries: Mechanism,Materials, and Characterization

Compared with conventional positive electrode materials in Li-ion batteries, Li-rich materials have a huge advantage of large specific capacities of >300 mAh g⁻¹. Anionic redox mechanism is proposed to explain the over-capacity, which means anions can participate in the redox process for charge compensation. The concept enriches the range and design considerations of high-energy-density positive electrode materials for both Li-ion and Na-ion batteries, which therefore arouses extensive attention. This review summarizes the progress of anionic redox in rechargeable batteries in recent years and discusses the fundamental mechanism that triggers anionic redox. Moreover, the state-of-the-art materials involving anionic redox are illustrated, accompanied by the challenges for practical applications. Furthermore, the common techniques for monitoring anionic redox are reviewed and compared for an advisable choice in future studies. Finally, the consideration and discussion for designing stable positive electrodes based on cationic and anionic redox are presented. The perspective is highlighted and this review provides a basic understanding of anionic redox in rechargeable batteries and paves the way to develop high-capacity positive electrodes for high-energy battery systems.     

Advanced QoS provisioning in IP networks: the European premium IP projects

This article describes the current evolution of QoS architectures, mechanisms, and protocols in the Internet, as it is ongoing in the framework of the European Union funded research projects on premium IP networks. A short review of the proposed standard approaches to QoS (e.g., differentiated services, integrated services, and label switching technologies) is given. Then we focus on the state-of-the-art architectures, mainly based on DiffServ concepts. Several issues arise when trying to implement these architectures in the real world: QoS aspects, network monitoring of the offered QoS, and end-user control of received QoS. The article then discusses the existing results and the current direction of European research and development in these areas.     

Mesoporous NiCo2O4 Nanowire Arrays Grown on Carbon Textiles as Binder‐Free Flexible Electrodes for Energy Storage

Binary metal oxides has been regarded as a promising class of electrode materials for high‐performance energy storage devices since it offers higher electrochemical activity and higher capacity than mono‐metal oxide. Besides, rational design of electrode architectures is an effective solution to further enhance electrochemical performance of energy storage devices. Here, the advanced electrode architectures consisting of carbon textiles uniformally covered by mesoporous NiCo₂O₄ nanowire arrays (NWAs) are successfully fabricated by a simple surfactant‐assisted hydrothermal method combined with a short post annealing treatment, which can be directly applied as self‐supported electrodes for energy storage devices, such as Li‐ion batteries, supercapacitors. The as‐prepared mesoporous NiCo₂O₄ nanowires consist of numerous highly crystalline nanoparticles, leaving a large number of mesopores to alleviate the volume change during the charge/discharge process. Electrode architectures presented here promise fast electron transport by direct connection to the growth substrate and facile ion diffusion path provided by both the abundant mesoporous structure in nanowires and large open spaces between neighboring nanowires, which ensures every nanowire participates in the ultrafast electrochemical reaction. Benefiting from the intrinsic materials and architectures features, the unique binder‐free NiCo₂O₄/carbon textiles exhibit high specific capacity/capacitance, excellent rate capability, and cycling stability.     

基于富勒烯类材料太阳能电池研究进展

从太阳能电池基本原理、新材料合成、活性层和修饰层的工艺改进、器件结构多样化以及电极材料的选取及工艺等方面介绍了基于富勒烯类材料的有机太阳能电池的研究进展,并探讨了今后有机薄膜器件研究的发展趋势。     

Flexible devices: from materials,architectures to applications

Flexible devices,such as flexible electronic devices and flexible energy storage devices,have attracted a significant amount of attention in recent years for their potential applications in modem human lives.The development of flexible devices is moving forward rapidly,as the innovation of methods and manufacturing processes has greatly encouraged the research of flexible devices.This review focuses on advanced materials,architecture designs and abundant applications of flexible devices,and discusses the problems and challenges in current situations of flexible devices.We summarize the discovery of novel materials and the design of new architectures for improving the performance of flexible devices.Finally,we introduce the applications of flexible devices as key components in real life.