Ultrahigh Electrical Conductivity of Graphene Embedded in Metals

Highly efficient conductors are strongly desired because they can lead to higher working performance and less energy consumption in their wide range applications. However, the improvements on the electrical conductivities of conventional conductors are limited, such as purification and growing single crystal of metals. Here, by embedding graphene in metals (Cu, Al, and Ag), the trade‐off between carrier mobility and carrier density is surmount in graphene, and realize high electron mobility and high electron density simultaneously through elaborate interface design and morphology control. As a result, a maximum electrical conductivity three orders of magnitude higher than the highest on record (more than 3,000 times higher than that of Cu) is obtained in such embedded graphene. As a result, using the graphene as reinforcement, an electrical conductivity as high as ≈117% of the International Annealed Copper Standard and significantly higher than that of Ag is achieved in bulk graphene/Cu composites with an extremely low graphene volume fraction of only 0.008%. The results are of significance when enhancing efficiency and saving energy in electrical and electronic applications of metals, and also of interest for fundamental researches on electron behaviors in graphene.     

Microencapsulated Carbon Black Suspensions for Restoration of Electrical Conductivity

Robust microcapsules are prepared with carbon black suspensions high in solids loading (up to 0.2 g/mL) for electrical conductivity restoration. Oxidized carbon black is rendered more hydrophobic through surface functionalization with octadecylamine by two different methods. Functionalization significantly improves dispersability and suspension stability of carbon black in hydrophobic solvents such as o‐dichlorobenzene (o‐DCB), enabling encapsulation by in situ emulsion polymerization. Upon crushing, microcapsules containing functionalized carbon black (FCB) suspensions exhibit significant particle release relative to microcapsules filled with unfunctionalized carbon black. Release of carbon black is further enhanced by the addition of two types of core thickeners, epoxy resin or poly 3‐hexylthiophene (P3HT). Full conductivity restoration (100% restoration efficiency) of damaged silicon anodes is achieved by crushing microcapsules containing FCB suspensions with P3HT. Hydrophobic surface functionalization of carbon black and the addition of core thickeners are both critical for achieving stable microcapsules capable of significant particle release and efficient conductivity restoration.     

Unleashing the Potential of Sodium-Ion Batteries: Current State and Future Directions for Sustainable Energy Storage

Rechargeable sodium-ion batteries (SIBs) are emerging as a viable alternative to lithium-ion battery (LIB) technology, as their raw materials are economical, geographically abundant (unlike lithium), and less toxic. The matured LIB technology contributes significantly to digital civilization, from mobile electronic devices to zero electric-vehicle emissions. However, with the increasing reliance on renewable energy sources and the anticipated integration of high-energy-density batteries into the grid, concerns have arisen regarding the sustainability of lithium due to its limited availability and consequent price escalations. In this context, SIBs have gained attention as a potential energy storage alternative, benefiting from the abundance of sodium and sharing electrochemical characteristics similar to LIBs. Furthermore, high-entropy chemistry has emerged as a new paradigm, promising to enhance energy density and accelerate advancements in battery technology to meet the growing energy demands. This review uncovers the fundamentals, current progress, and the views on the future of SIB technologies, with a discussion focused on the design of novel materials. The crucial factors, such as morphology, crystal defects, and doping, that can tune electrochemistry, which should inspire young researchers in battery technology to identify and work on challenging research problems, are also reviewed.     

3D‐Printed All‐Fiber Li‐Ion Battery toward Wearable Energy Storage

Conventional bulky and rigid power systems are incapable of meeting flexibility and breathability requirements for wearable applications. Despite the tremendous efforts dedicated to developing various 1D energy storage devices with sufficient flexibility, challenges remain pertaining to fabrication scalability, cost, and efficiency. Here, a scalable, low‐cost, and high‐efficiency 3D printing technology is applied to fabricate a flexible all‐fiber lithium‐ion battery (LIB). Highly viscous polymer inks containing carbon nanotubes and either lithium iron phosphate (LFP) or lithium titanium oxide (LTO) are used to print LFP fiber cathodes and LTO fiber anodes, respectively. Both fiber electrodes demonstrate good flexibility and high electrochemical performance in half‐cell configurations. All‐fiber LIB can be successfully assembled by twisting the as‐printed LFP and LTO fibers together with gel polymer as the quasi‐solid electrolyte. The all‐fiber device exhibits a high specific capacity of ≈110 mAh g^?1 at a current density of 50 mA g^?1 and maintains a good flexibility of the fiber electrodes, which can be potentially integrated into textile fabrics for future wearable electronic applications.     

Surface Reconstruction Limited Conductivity in Block‐Copolymer Li Battery Electrolytes

Solid polymer electrolytes for lithium batteries promise improvements in safety and energy density if their conductivity can be increased. Nanostructured block‐copolymer electrolytes specifically have the potential to provide both good ionic conductivity and good mechanical properties. This study shows that the previously neglected nanoscale composition of the polymer electrolyte close to the electrode surface has an important effect on impedance measurements, despite its negligible extent compared to the bulk electrolyte. Using standard stainless steel blocking electrodes, the impedance of lithium salt‐doped poly(isoprene‐b‐styrene‐b‐ethylene oxide) (ISO) exhibits a marked decrease upon thermal processing of the electrolyte. In contrast, covering the electrode surface with a low molecular weight poly(ethylene oxide) (PEO) brush results in higher and more reproducible conductivity values, which are insensitive to the thermal history of the device. A qualitative model of this effect is based on the hypothesis that ISO surface reconstruction at the different electrode surfaces leads to a change in the electrostatic double layer, affecting electrochemical impedance spectroscopy measurements. As a main result, PEO‐brush modification of electrode surfaces is beneficial for the robust electrolyte performance of PEO‐containing block‐copolymers and may be crucial for their accurate characterization and use in Li‐ion batteries.     

Optimized Cathode for High-Energy Sodium-Ion Based Dual-Ion Full Battery with Fast Kinetics

The most used systems based on the graphite-based cathode show unsatisfactory performance in dual-ion batteries. Developing new type cathode materials with high capacity for new type anions storage is an effective way to improve the total performance of dual-ion batteries. Herein, a protonated polyaniline (P-PANI) cathode is prepared to realize efficient and stable storage of ClO₄^–, and a high reversible capacity of 143 mAh g⁻¹ at 0.2 A g⁻¹ after 200 cycles can be obtained, which is competitive compared with common graphite cathodes. In addition, the highly reversible coordination storage mechanism between ClO₄⁻ and P-PANI cathode is indicated, rather than the labored intercalation reactions between PF₆⁻ and graphite. Subsequently, a full cell (P-PANI//N-PDHC) fabricated with a P-PANI cathode and hard carbon anode (N-PDHC) can deliver a high energy density of 284 Wh kg^–1 for 2000 cycles at 2 A g^–1, and the relevant pouch-type full cell can easily power a smartphone. In general, this work may promote the exploitation of sodium-based dual-ion batteries in practical application.     

Zr-MOF-Enabled Controllable Ion Sieving and Proton Conductivity in Flow Battery Membrane

Membrane with ordered channels is the key to controlling ion sieving and proton conductivity in flow batteries. However, it remains a great challenge for finely controlling the nanochannels of polymeric membranes. Herein, two types of acid-stable Zr-metal organic framework (MOF-801 and MOF-808) with variable pore structures and channel properties are introduced as fillers into a non-fluorinated sulfonated poly (ether ether ketone) (SPEEK). The membrane incorporated with MOF-801 of a smaller triangular window (≈3.5 Å) successfully translates the molecular sieving property into the flow battery membrane, resulting in enhanced coulombic efficiency (98.5–99.2%) at 40–120 mA cm⁻² compared with the pristine SPEEK membrane (97.1–98.5%). In contrast, more protophilic internal interconnected channels of MOF-808 yield faster proton highway, leading to a significant increase of voltage efficiency (93.7–84.1%) at 40–120 mA cm⁻² compared with the pristine SPEEK membrane (91.7–78.9%). By regulating the ion sieving and proton conductivity, MOF-801/MOF-808 binary composite membrane exhibits synchronously improved performance in the vanadium redox flow battery system. The revealed structure–property relationship in the Zr-MOFs-based membranes provides a general guideline to design new proton exchange membranes with ordered channels for flow battery application.     

SDH设备中电接口信号传输距离的计算

从理论出发,应用传输线的导体衰减系数和电接口的输入允许衰减等物理概念,介绍了一种简单易用的电接口信号传输距离的工程计算方法.     

Interactions between Primary Neurons and Graphene Films with Different Structure and Electrical Conductivity

Graphene-based materials represent a useful tool for the realization of novel neural interfaces. Several studies have demonstrated the biocompatibility of graphene-based supports, but the biological interactions between graphene and neurons still pose open questions. In this work, the influence of graphene films with different characteristics on the growth and maturation of primary cortical neurons is investigated. Graphene films are grown by chemical vapor deposition progressively lowering the temperature range from 1070 to 650 °C to change the lattice structure and corresponding electrical conductivity. Two graphene-based films with different electrical properties are selected and used as substrate for growing primary cortical neurons: i) highly crystalline and conductive (grown at 1070 °C) and ii) highly disordered and 140-times less conductive (grown at 790 °C). Electron and fluorescence microscopy imaging reveal an excellent neuronal viability and the development of a mature, structured, and excitable network onto both substrates, regardless of their microstructure and electrical conductivity. The results underline that high electrical conductivity by itself is not fundamental for graphene-based neuronal interfaces, while other physico–chemical characteristics, including the atomic structure, should be also considered in the design of functional, bio-friendly templates. This finding widens the spectrum of carbon-based materials suitable for neuroscience applications.     

Stabilizing Polymer–Lithium Interface in a Rechargeable Solid Battery

Solid polymer electrolytes (SPEs) are promising candidates for developing high‐energy‐density Li metal batteries due to their flexible processability. However, the low mechanical strength as well as the inferior interfacial regulation of ions between SPEs and Li metal anode limit the suppress ion of Li dendrites and destabilize the Li anode. To meet these challenges, interfacial engineering aiming to homogenize the distribution of Li⁺/electron accompanied with enhanced mechanical strength by Mg₃N₂ layer decorating polyethylene oxide is demonstrated. The intermediary Mg₃N₂ in situ transforms to a mixed ion/electron conducting interlayer consisting of a fast ionic conductor Li₃N and a benign electronic conductor Mg metal, which can buffer the Li⁺ concentration gradient and level the nonuniform electric current distribution during cycling, as demonstrated by a COMSOL Multiphysics simulation. These characteristics endow the solid full cell with a dendrite‐free Li anode and enhanced cycling stability and kinetics. The innovative interface design will accelerate the commercial application of high‐energy‐density solid batteries.     

Multi-Fidelity High-Throughput Optimization of Electrical Conductivity in P3HT-CNT Composites

Combining high-throughput experiments with machine learning accelerates materials and process optimization toward user-specified target properties. In this study, a rapid machine learning-driven automated flow mixing setup with a high-throughput drop-casting system is introduced for thin film preparation, followed by fast characterization of proxy optical and target electrical properties that completes one cycle of learning with 160 unique samples in a single day, a > 10 ×  improvement relative to quantified, manual-controlled baseline. Regio-regular poly-3-hexylthiophene is combined with various types of carbon nanotubes, to identify the optimum composition and synthesis conditions to realize electrical conductivities as high as state-of-the-art 1000 S cm⁻¹. The results are subsequently verified and explained using offline high-fidelity experiments. Graph-based model selection strategies with classical regression that optimize among multi-fidelity noisy input-output measurements are introduced. These strategies present a robust machine-learning driven high-throughput experimental scheme that can be effectively applied to understand, optimize, and design new materials and composites.     

In Situ Electrical Network Activation and Deactivation in Short Carbon Fiber Composites via 3D Printing

Prior studies on carbon-filler based, conductive polymer composites have mainly investigated how conductive filler morphology and concentration can tailor a material's electrical conductivity and overlooks the effects of filler alignment due to the difficulty to control and quickly quantify the filler alignment. Here, direct ink write 3D printing's unique ability is utilized to control carbon fiber alignment with a single process parameter, velocity ratio, to instantaneously activate or deactivate the electrical network in composites. Maximum electrical conductivity is achieved by randomly aligning carbon fibers that enhances the chance of direct fiber-to-fiber contact and, thus, activating the electrical network. However, aligning the fibers by increasing the velocity ratio disrupts the electrical network by minimizing fiber-to-fiber contact that resulted in a drastic decrease in electrical conductivity by as much as five orders of magnitude in both short and long carbon fiber composites. With this study, this study demonstrates that electrically conductive or insulative composites can be fabricated sequentially with a single ink. This novel ability to instantaneously control the electrical conductivity of carbon fiber reinforced composites allow to directly embed conductive pathways into designs to 3D print multifunctional composites that are capable of localized heating and self-sensing.     

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.     

Engineering Solid Electrolyte Interface at Nano-Scale for High-Performance Hard Carbon in Sodium-Ion Batteries

Engineering the structure and chemistry of solid electrolyte interface (SEI) on electrode materials is crucial for rechargeable batteries. Using hard carbon (HC) as a platform material, a correlation between Na⁺ storage performance, and the properties of SEI is comprehensively explored. It is found that a “good” SEI layer on HC may not be directly associated with certain kinds of SEI components, such as NaF and Na₂O. Whereas, arranging nano SEI components with refined structures constructs the foundation of “good” SEI that enables fast Na⁺ storage and interface stability of HC in Na-ion batteries. A layer-by-layer SEI on HC with inorganic-rich inner layer and tolerant organic-rich outer flexible layer can facilitate excellent rate and cycling life. Besides, SEI layer as the gate for Na⁺ from electrolyte to HC electrode can modulate interfacial crystallographic structures of HC with pillar-solvent that function as “pseudo-SEI” for fast and stable Na⁺ storage in optimal 1 m NaPF₆-TEGDME electrolytes. Such a layer-by-layer SEI combined with a “pseudo-SEI” layer for HC enables an outstanding rate of 192 mAh g⁻¹ at 2 C and stable cycling over 1100 cycles at 0.5 C. This study provides valuable guidance to improve the electrochemical performance of electrode materials through regulation of SEI in optimal electrolytes.     

2D Dynamic Heterogeneous Interface Coupling Endowing Extra Zn2+ Storage

Aqueous zinc-ion battery (AZIBs) is expected to be an ideal device for large-scale energy storage for its high safety and low cost. However, it is still a challenge to achieve both high energy density and high stability. Herein, in situ liquid-phase growth exfoliation is developed to obtain V₅O₁₂ nanosheets, which is then combined with Ti₃C₂ nanosheets to construct two-dimensional heterostructure (2D HVO@Ti₃C₂) with interfacial V O Ti bonds. 2D HVO@Ti₃C₂ exhibits a dynamic interface coupling during discharging/charging, accompanied by break/reconstruction of interfacial V O Ti bonds. The dynamic interface coupling provides a reversible electron transfer channel and endows the inert Ti₃C₂ with electrochemical activity in AZIBs, making it an additional electron acceptor and donor, and promoting the insertion of more Zn²⁺. Therefore, a capacity beyond the theoretical capacity of HVO is obtained for the HVO@Ti₃C₂. Additionally, the reversible 2D dynamic interface coupling can also effectively alleviate the structural damage during the cycling process. Then, the ultra-high capacity (457.1 mAh g^-1 at 0.2 A g^-1, over 600 mAh g^-1 based on the mass of HVO) and high stability (88.9% capacity retention after 1000 cycles at 5 A g^-1) are achieved. This interface coupling mechanism provides an exciting strategy for the high energy density and high stability of AZIBs.     

Harnessing Selective Exsolution of Sn Metal to Enhance Electrical Conductivity in Oxygen-Deficient Perovskite Stannates

The versatile application of newly discovered oxide semiconductors calls for developing a simple process to generate conducting carriers. High-temperature reduction treatment leads to electrical conduction in perovskite stannate semiconductors, but carrier concentration is poorly controlled and inconsistently reported in BaSnO_3−δ films after the reduction process so far. Here, a new strategy to enhance the electrical conductivity of BaSnO_3−δ films is demonstrated by exploiting selective exsolution of Sn metals in the perovskite framework. Due to strong dependence of conductivity on initial Sn/Ba cation ratio in the reduced BaSnO_3−δ films, interestingly, only Sn-excess BaSnO_3−δ films show a dramatic increase of carrier concentration ( ∆ n_3D  = 5–7 × 10¹⁹ cm⁻³) after high-temperature reduction; exceptionally high electrical conductivity (σ  ≈  6000 S cm⁻¹) is achieved in reduced Sn-excess (La, Ba)SnO_3−δ films, which exceed full activation of La dopants in untreated (La, Ba)SnO₃. By multiple characterizations combined with theoretical calculation, it is disclosed that a small fraction of segregated β-Sn nanoparticles is likely to contribute the additional source of n_3D in the BaSnO_3−δ matrix as a result of spontaneous charge transfer from the segregated β-Sn metallic phase to BaSnO_3−δ. These original results propose a simple strategy to further increase electrical conductivity in perovskite oxide semiconductors by non-stoichiometry-driven metal exsolution.     

Electrocatalysis of Fe-N-C Bonds Driving Reliable Interphase and Fast Kinetics for Phosphorus Anode in Sodium-Ion Batteries

Phosphorus exhibits high capacity and low redox potential, making it a promising anode material for future sodium-ion batteries. However, its practical applications are confined by poor durability and sluggish kinetics. Herein, an innovative in-situ electrochemically self-driven strategy is presented to embed phosphorus nanocrystal (≈10 nm) into a Fe-N-C-rich 3D carbon framework (P/Fe-N-C). This strategy enables rapid and high-capacity sodium ion storage. Through a combination of experimental assistance and theoretical calculations, a novel synergistic catalytic mechanism of Fe-N-C is reasonably proposed. In detail, the electrochemical formation of Fe-N-C catalytic sites facilitates the release of fluorine in ester-based electrolyte, inducing Na⁺-conducting-enhanced solid-electrolyte interphase. Furthermore, it also effectively induces the dissociation energy of the P-P bond and promotes the reaction kinetics of P anode. As a result, the unconventional P/Fe-N-C anode demonstrates outstanding rate-capability (267 mAh g⁻¹ at 100 A g⁻¹) and cycling stability (72%, 10 000 cycles). Notably, the assembled pouch cell achieves high-energy density of 220 Wh kg⁻¹.     

飞机/悬挂物电气接口中的数字信号反射分析

为了研究飞机/悬挂物电气接口中的数字信号反射规律,采用原理分析和实验分析相结合的方法,分析了若干典型总线网络的信号反射现象,结果显示飞机/悬挂物电气接口中存在信号失真,且不同位置和不同配置中信号失真存在差异。根据试验结果,可采取如下措施使信号失真在允许范围之内:耦合器之间不宜太靠近,减少耦合器的规模,提供足够的信号幅值,尽量缩短短截线的长度等。     

Nitrogen as An Anionic Center/Dopant for Next-Generation High-Performance Lithium/Sodium-Ion Battery Electrodes: Key Scientific Issues,Challenges and Perspectives

The rapid progress of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have extensively promoted the rechargeable battery technology in the fields of electric vehicles and grid scale energy storage systems. With recent highly effective nitrogen doping strategy in terms of improving the overall electrochemical performance in various sorts of battery systems, the bulk N doping/substitution lays on the core innovations toward structural manipulation toward higher ionic conductivity, elevated reversible working plateau, etc. However, the key scientific and practical issues such as the phase formation process, phase transition kinetics, valence change and anionic/cationic physical/chemical behaviors still leave open questions in the direction of their real applications in the next-generation battery technology. In light of this, a timely and in-depth perspective is provided on the development of the bulk N doping/substitution strategy of these high-performance electrodes of LIBs/SIBs adapting nitrogen as anionic center/dopant. Both the variations of phase and structural constitutions, alkali ion storage mechanism, electrochemical change, and the alkali ion kinetics, which are the key scientific parts for the future explorations of these novel and promising electrodes are highlighted. The most urgent and critical commercial obstacles or challenges towards cost-efficiency synthetic approach without excessive environmental pollutions are also outlined. With the participation of nitrogen in bulk crystals , the overall specific energy density of next-generation alkali ion batteries will be reasonably promoted and accelerated in the near future.