Electrical Conductive Network Research Articles

A Chemo-Mechanical Particle Model for the Fabrication and Cyclic Expansion of Silicon Composite Solid-State Batteries

All-Solid-State Batteries (ASSBs) are increasingly perceived as a viable substitute to Li-ion batteries, primarily due to their enhanced safety and energy density. ASSBs utilize a non-flammable solid electrolyte, significantly reducing the risk of fire hazards. Furthermore, they can operate under a broader temperature and voltage spectrum. This research aims to optimize the composition of anode electrode materials, comprised of a particle mixture of Active Material (AM), Solid Electrolyte (SE), and conductive additive.Graphite, a frequently used AM, is favored for its low voltage characteristics and its low volume expansion during charge cycling. Additionally, graphite's low Young Modulus is beneficial in preventing the build-up of substantial stresses within the battery cell. Silicon (Si) is another appealing material due to its high gravimetric capacity, which is up to ten times greater than that of graphite. However, during Li insertion, the crystalline structure transitions to an amorphous state, resulting in a substantial expansion of up to 300%, which triggers a significant accumulation of stress.Numerous strategies have been explored to alleviate the stress build-up resulting from expansion by adding graphite or carbon nanotubes (CNTs). The latter provides void spaces which can accommodate the volumetric expansion. Furthermore, the CNTs possess the capacity to retain the electrode's structure during volume expansion, which is advantageous for maintaining structural integrity, preserving solid-solid contacts, and enhancing the electrical conduction network. Owing to these factors, ASSBs with the addition of CNTs have demonstrated improved cycling performance. 1 Simulating Si composite solid-state anodes presents a significant challenge due to the stress induced by localized Si particles. The substantial expansion of Si can lead to the formation of shell voids in minute localized regions surrounding the microscopic Si particles. This complexity makes it difficult to simulate the dynamics using traditional finite element (FE) based mechanical models. An alternative solution is to employ the Discrete Element Method (DEM) which is a type of particle-based models that solve for Newton's laws of motion for each particle. While continuum models are instrumental in deterministically calculating the properties of bulk materials, DEMs can be utilized to compute particle slippage and the evolution of void regions between individual particles, which influence the local contact area of solid-solid interactions.In our previous research,2 we developed a multiscale chemo-mechanical DEM model for Si anode solid-state batteries. This model encompasses two stages: fabrication and cell operation. During the fabrication stage, particles were simulated within a high-pressure mold, for which we devised an elasto-plastic contact model. Throughout the cell operation stage, we simulated Li insertion and AM volume expansion. However, in current study it was observed that during charge cycling in confined cell volume, the pressure exceeded levels that are acceptable for practical applications. Furthermore, during discharge, the contact areas between particles declined and AM progressively lost its ability to form an electronic percolative chain, reducing the discharge capacity.We successfully incorporated CNTs into the DEM model by linking particles into elongated fibers, each with robust adhesive fusion bonds. The electronic percolation network and interface contact areas saw significant improvement with the addition of CNTs. By further implementing this model, we can determine the optimal composition of Si, graphite and CNTs based on several performance indicators, including the electrode's power density and capacity fade. The study will be broadened to simulate various geometrical configurations, such as a particle mixture of Si and graphite, and coated Si and SE particles on CNT structures. Acknowledgements We gratefully acknowledge the support of the Japan Science and Technology Agency (JST) through the JST-Mirai Program, Grant number JPMJMI24G1. References L. Hu, X. Yan, Z. Fu, J. Zhang, Y. Xia, W. Zhang, Y. Gan, X. He, and H. Huang, ACS Appl. Energy Mater., 5, 14353–14360 (2022).M. So, S. Yano, A. Permatasari, T. D. Pham, K. Park,. and G. Inoue, Journal of Power Sources, 546, 231956 (2022).

Understanding the Carbon Additive/Sulfide Solid Electrolyte Interface in Nickel-Rich Cathode Composites and Prioritizing the Corresponding Interplay between the Electrical and Ionic Conductive Networks to Enhance All-Solid-State-Battery Rate Capability.

All-solid-state lithium batteries, including sulfide electrolytes and nickel-rich layered oxide cathode materials, promise safer electrochemical energy storage with high gravimetric and volumetric densities. However, the poor electrical conductivity of the active material results in the requirement for additional conducive additives, which tend to react negatively with the sulfide electrolyte. The fundamental scientific principle uncovered through this work is simple and suggests that the electrical network benefits associated with the introduction of short-length carbons will eventually be overpowered by the increase in bulk resistance associated with their instability in the sulfide electrolyte. However, applying just the right amount of short carbon fibres minimizes degradation of the sulfide solid electrolyte and maximizes the electron movement. Therefore, we propose the application of a low-weight-percent carbon nanotubes (CNTs) coating on the nickel-rich cathode LiNi0.8Co0.1Mn0.1O2 (NCM811) along with large-aspect-ratio carbon nanofibers (CNFs) as the primary conductive additive. When only 0.3 wt % CNTs was utilized with 4.7 wt % CNFs, an initial Coulombic efficiency of 83.55% at 0.05C and a notably excellent capacity retention of 90.1% over 50 cycles at 0.5C were achieved along with a low ionic resistance. This work helps to confirm the validity of applying short carbon pathways in sulfide-electrolyte-based cathode composites and proposes their combination with a larger primary carbon additive as a solution to the ongoing all-solid-state battery rate and instability issues.

Design and fabrication of NiCo2S4@rGO as an efficient Pt free triiodide reducing agent for dye-sensitized solar cell application

Exploiting efficient Pt-free counter-electrode materials with low cost and highly catalytic property is a hot topic in the field of Dye-sensitized solar cells (DSCs). Here, NiCo2S4/reduced graphene oxide (RGO) was prepared via an economical hydrothermal ynthesis route, and the as-prepared composite exhibited comparable electrocatalytic property with the conventional Pt electrode as the counter-electrode. Enhanced optoelectronic, optical and structural characteristics have been attained over the constructed heterojunction. Band gap energy of NiCo2S4 (2.35 eV) was suppressed to 2.11 eV owing to its supporting with 10 wt.% rGO bringing about upgraded absorption of visible light. Electrochemical studies confirmed the synergetic effect of nickel and cobalt ions with the high electrical conductive rGO networks that enhance the electrocatalytic activity of NiCo2S4 nanostructures. The efficiency achieved for the NiCo2S4@rGO counter electrode (CE) based DSSC is 8.17%, which is remarkably higher than that of pristine NiCo2S4 (7.31%), and Pt (7.14%) under the same experimental conditions. In outline, given their innovative synthesis approach, affordability, and remarkable electrocatalytic attributes, the newly developed NiCo2S4@rGO counter electrodes stand out as potent contenders in future dye-sensitized solar cell applications.

A Regulable Polyporous Graphite/Melamine Foam for Heat Conduction, Sound Absorption and Electromagnetic Wave Absorption.

To reduce electromagnetic interference and noise pollution within communication base stations and servers, it is necessary for electromagnetic wave absorption (EWA) materials to transition from coating to multifunctional devices. Up to now, the stable and effective integration of multiple functions into one material by a simple method has remained a large challenge. Herein, a foam-type microwave absorption device assembled with multicomponent organic matter and graphite powder is synthesized by a universal combination process. Melamine and phenolic aldehyde amine work as the skeleton and cementing compound, respectively, in which graphite is embedded in the cementing compound interconnected into the mesoscopic 3D electric conductive and heat conductive network. Interestingly, the prepared flexible graphite/melamine foam (CMF) delivers a great EWA performance, with a great effective absorption bandwidth of 9.8GHz, ultrathin thickness of 2.60mm, and a strong absorption reflection loss of -41.7dB. Moreover, the CMF possesses porosity and flexibility, endowing it with sound absorption ability. The CMF is unique in its integration of EWA, heat conduction, sound absorption, and mechanical robustness, as well as its cost-effective and scalable manufacturing. These attributes make CMF promising as a multifunctional device widely used in communication base stations, servers, and chips protection.

Nanoscale Dispersion of Carbon Nanotubes in a Metal Matrix to Boost Thermal and Electrical Conductivity via Facile Ball Milling Techniques.

Carbon nanotube (CNT)/metal composites have attracted much attention due to their enhanced electrical and thermal performance. How to achieve the scalable fabrication of composites with efficient dispersion of CNTs to boost their performance remains a challenge for their wide realistic applications. Herein, the nanoscale dispersion of CNTs in the Stannum (Sn) matrix to boost thermal and electrical conductivity via facile ball milling techniques was demonstrated. The results revealed that CNTs were tightly attached to metal Sn, resulting in a much lower resistivity than that of bare Sn. The resistivity of Sn with 1 wt.% and 2 wt.% CNTs was 0.087 mΩ·cm and 0.056 mΩ·cm, respectively. The theoretical calculation showed that there was an electronic state near the Fermi level, suggesting its electrical conductivity had been improved to a certain extent. In addition, the thermal conductivity of Sn with 2 wt.% CNTs was 1.255 W·m-1·K-1. Moreover, Young's modulus of the composites with CNTs mass fraction of 10 wt.% had low values (0.933 MPa) under low strain conditions, indicating the composite shows good potential for various applications with different flexible requirements. The good electrical and thermal conductive CNT networks were formed in the metal matrix via facile ball milling techniques. This strategy can provide guidance for designing high-performance metal samples and holds a broad application potential in electronic packaging and other fields.

Improving the anti-corrosive performance of epoxy/zinc composite coatings with N-doped 3D reduced graphene oxide

Three-dimensional reduced graphene oxide (3DRGO) doped with N heteroatoms was innovatively incorporated into a Zn-containing epoxy (EP/Zn) composite coating. Comprehensive investigations that introducing 3DRGO significantly improved the anti-corrosion performance of the coating, and the optimal 3DRGO content was only 0.05 wt%. The effects of both the spatial structure and chemical doping of graphene on the surface protection performance of their EP/Zn coating were revealed for the first time. Compared with the conventional 2-dimensional reduced GO (RGO) sheets and 3D graphene (3DG) with similar 3D structures, 3DRGO exhibited superior effect on promoting the corrosion resistance of its composite coating. This can be attributed to not only the unique 3D porous strut structure of 3DRGO, but also its N-doping, which plays important roles in increasing its interaction with the epoxy matrix, preventing 3DRGO agglomeration, improving the barrier property of the coating, facilitating the construction of an electrical conduction network between Zn particles, and exploiting the cathodic protection function of Zn more efficiently.

Hierarchically structured electrode materials derived from metal-organic framework/vertical graphene composite for high-performance flexible asymmetric supercapacitors

Low conductivity of metal-organic frameworks limits their applications in electrochemical energy storage and conversion. To overcome this shortcoming, we synthesized the zeolitic imidazolate framework-67 on the vertical graphene (VG) surface with abundant defects grown on carbon cloth (ZIF-67-VG-CC). Based on “one-for-two” strategy, the Co3O4 nanoparticles (Co3O4-VG-CC) and nanoporous carbon (NC-VG-CC) can be derived from ZIF-67-VG-CC via selective pyrolysis in the controlled atmospheres. In the hierarchically structured Co3O4-VG-CC and NC-VG-CC, the Co3O4 nanoparticles with a size of 20 nm and N-doped porous carbons were uniformly dispersed on the VG surface, as confirmed by electron microscopies. Both the Co3O4-VG-CC and NC-VG-CC yield high specific capacitance and excellent rate capability. After assembling these two electrodes to make an asymmetric supercapacitor, the Co3O4-VG-CC//NC-VG-CC delivered a maximum energy density of 43.75 Wh/kg at a power density of 5.2 kW/kg as well as excellent cycling stability with 91.5 % specific capacitance retained after 20,000 charge-discharge cycles. All these results should be ascribed to that the VG sheets possess their high electrical conductivity and 3D network structure, and provide the hierarchical supports for the uniform distribution of the ZIF-67-dervied Co3O4 nanoparticles and NC materials, which are beneficial to the fast electron and ion transfer in the electrodes.

Simulation Studies Underlying the Influence of Filler Orientation on the Electrical Properties of Short Carbon Fiber Conductive Polymer Composites: Implications for Electrical Conductivity Regulation of Micro/Nanocomposites

The electrical properties of conductive polymer composites are critical in applications, and the electrical conductivity regulation through micro/nanofiller orientation is attracting broad attention. For short carbon fiber (SCF) conductive polymer composites (SCFCPCs), the electrical properties and SCF conductive network topology of SCFCPCs with different SCF orientations are analyzed with a numerical model. The results demonstrate that an increase in the degree of SCF orientation from 0 (SCFs perpendicular to conductivity direction) to 1 (SCFs parallel to conductivity direction) first leads to a corresponding increase and then a decrease in the electrical conductivity of SCFCPCs. The highest electrical conductivity is achieved while the degree of SCF orientation is increased to approximately 0.6, which is a higher SCF orientation state compared to random orientation. Moreover, it is identified that more SCFs in conductive networks do not necessarily guarantee a higher electrical conductivity. The electrical conductivity of the SCF conductive networks also depends on the degree of SCF orientation. Evidently, the less-oriented SCFs tend to build in-layer conductive networks, while the highly oriented SCFs tend to build interlayer ones, which apply a greater contribution to the electrical conductivity. Overall, the results of this study reveal why the highest electrical conductivity occurs at a higher SCF orientation rather than a random SCF orientation. The clarified influence and mechanism provide indications for the electrical conductivity regulation of micro/nanocomposites by adjusting the conductive filler orientation.

Biomimetic Construction of Ferrite Quantum Dot/Graphene Heterostructure for Enhancing Ion/Charge Transfer in Supercapacitors.

Spinel ferrites are regarded as promising electrode materials for supercapacitors (SCs) in virtue of their low cost and high theoretical specific capacitances. However, bulk ferrites suffer from limited electrical conductivity, sluggish ion transport, and inadequate active sites. Therefore, rational structural design and composition regulation of the ferrites are approaches to overcome these limitations. Herein, a general biomimetic mineralization synthetic strategy is proposed to synthesize ferrite (XFe2 O4 , X = Ni, Co, Mn) quantum dot/graphene (QD/G) heterostructures. Anchoring ferrite QD on the graphene sheets not only strengthens the structural stability, but also forms the electrical conductivity network needed to boost the ion diffusion and charge transfer. The optimized NiFe2 O4 QD/G heterostructure exhibits specific capacitances of 697.5 F g-1 at 1 A g-1 , and exceptional cycling performance. Furthermore, the fabricated symmetrical SCs deliver energy densities of 24.4 and 17.4Wh kg-1 at power densities of 499.3 and 4304.2W kg-1 , respectively. Density functional theory calculations indicate the combination of NiFe2 O4 QD and graphene facilitates the adsorption of potassium atoms, ensuring rapid ion/charge transfer. This work enriches the application of the biomimetic mineralization synthesis and provides effective strategies for boosting ion/charge transfer, which may offer a new way to develop advanced electrodes for SCs.

Electrostatic Interaction‐directed Construction of Hierarchical Nanostructured Carbon Composite with Dual Electrical Conductive Networks for Zinc‐ion Hybrid Capacitors with Ultrastability

Metal–organic framework (MOF)‐derived carbon composites have been considered as the promising materials for energy storage. However, the construction of MOF‐based composites with highly controllable mode via the liquid–liquid synthesis method has a great challenge because of the simultaneous heterogeneous nucleation on substrates and the self‐nucleation of individual MOF nanocrystals in the liquid phase. Herein, we report a bidirectional electrostatic generated self‐assembly strategy to achieve the precisely controlled coatings of single‐layer nanoscale MOFs on a range of substrates, including carbon nanotubes (CNTs), graphene oxide (GO), MXene, layered double hydroxides (LDHs), MOFs, and SiO2. The obtained MOF‐based nanostructured carbon composite exhibits the hierarchical porosity (Vmeso/Vmicro: 2.4), ultrahigh N content of 12.4 at.% and “dual electrical conductive networks.” The assembled aqueous zinc‐ion hybrid capacitor (ZIC) with the prepared nanocarbon composite as a cathode shows a high specific capacitance of 236 F g−1 at 0.5 A g−1, great rate performance of 98 F g−1 at 100 A g−1, and especially, an ultralong cycling stability up to 230 000 cycles with the capacitance retention of 90.1%. This work develops a repeatable and general method for the controlled construction of MOF coatings on various functional substrates and further fabricates carbon composites for ZICs with ultrastability.

Highly stable few-layer V2CTx MXene/Carbon nanotube structure with restrained restacking for lithium ion storage.

V2CTx MXene has shown potential as an electrode material for lithium-ion batteries (LIBs) due to its high theoretical capacity. However, most reports on V2CTx are confined to multilayer structures in LIBs, and V2CTx nanosheets have a serious restacking problem, which results in their low cyclic stability. Herein, we report the synthesis of few-layer V2CTx/carbon nanotubes (CNTs) composite by tetramethylammonium hydroxide (TMAOH) delamination and electrostatic flocculation of NH4+ ions. Few-layer V2CTx nanosheets with crimped structure can effectively restrain restacking and guarantee full utilization of active surface area. Moreover, with the introduction of CNTs, a developed electrical conductivity network was formed, and CNTs provided structural support for the sheets further restraining their restacking, and ensuring their stable structure during the charge and discharge process even at high rates. This made the few-layer V2CTx/CNT to exhibit a high specific capacitance of 621 mAh/g after 100 cycles at 0.1 A/g, and outstanding rate performance of 290 mAh/g at 5 A/g. Furthermore, the few-layer V2CTx/CNT electrode showed excellent cycling stability with 82.1% capacitance retention after 2000 cycles at 5 A/g. This shows it has significant potential for lithium-ion batteries applications.

Carbon foam/reduced graphene oxide/paraffin composite phase change material for electromagnetic interference shielding and thermal management

To address the issues of electromagnetic interference (EMI) shielding and thermal management during operation of electronic devices, carbon foam/reduced graphene oxide/paraffin dual-functional composite phase change material (c-MG/PA) is fabricated via reductive assembly and vacuum impregnation. The carbonized melamine foam and graphene jointly construct a three-dimensional electrical conductive and thermal conductive synergistic network. EMI shielding efficiency of c-MG/PA at thickness of 2 mm is up to 49 dB dominated by the electromagnetic absorption mechanism of the double conductive carbon network, far outstripping the commercial application standard of 20 dB. The phase change enthalpy of c-MG/PA reaches at least 196.3 J·g−1, and the relative enthalpy efficiency is above 97.4 %. Because of the enhancement of three-dimensional heat transfer network, the thermal conductivity of c-MG/PA is 324 % higher than that of paraffin. By using c-MG/PA as thermal management material in analog electronic chip, the chip temperature remarkably drops by 17.1 °C. In addition, c-MG/PA also exhibits superior shape stability, cycling stability and thermal stability, ensuring the reliability and security for long-term use in electronic devices. The results reveal that c-MG/PA possesses great application potential in EMI shielding and thermal management.

High Electrical Conductivity and Low Temperature Resistant Double Network Hydrogel Ionic Conductor as a Flexible Sensor and Quasi‐Solid Electrolyte

AbstractThe existence of large amounts of water in hydrogel electrolytes makes them inevitably freeze at low temperatures, which causes them to lose properties such as flexibility or electrical conductivity. It limits the application of hydrogel electrolytes at low temperatures. Here, we designed hydrogels with interpenetrating double network structure based on polyacrylamide and agar. By doping a high concentration of LiCl as the conducting material, a continuous ion‐conducting path was formed. The conductivity reached 2.18 S/m at 25 °C and 1.58 S/m at −30 °C. The prepared hydrogel electrolytes exhibit good mechanical and electrochemical properties to meet the needs of different application situations. A wearable sensor with hydrogel electrolytes was demonstrated. The wearable sensor can be attached to a part of the human body and can successfully detect various human movements. The wearable sensors can be used as temperature sensors in addition to detecting motion, which shows an encouraging and powerful utility in wearable electronic devices.

PLD3 affects axonal spheroids and network defects in Alzheimer’s disease

The precise mechanisms that lead to cognitive decline in Alzheimer’s disease are unknown. Here we identify amyloid-plaque-associated axonal spheroids as prominent contributors to neural network dysfunction. Using intravital calcium and voltage imaging, we show that a mouse model of Alzheimer’s disease demonstrates severe disruption in long-range axonal connectivity. This disruption is caused by action-potential conduction blockades due to enlarging spheroids acting as electric current sinks in a size-dependent manner. Spheroid growth was associated with an age-dependent accumulation of large endolysosomal vesicles and was mechanistically linked with Pld3—a potential Alzheimer’s-disease-associated risk gene1 that encodes a lysosomal protein2,3 that is highly enriched in axonal spheroids. Neuronal overexpression of Pld3 led to endolysosomal vesicle accumulation and spheroid enlargement, which worsened axonal conduction blockades. By contrast, Pld3 deletion reduced endolysosomal vesicle and spheroid size, leading to improved electrical conduction and neural network function. Thus, targeted modulation of endolysosomal biogenesis in neurons could potentially reverse axonal spheroid-induced neural circuit abnormalities in Alzheimer’s disease, independent of amyloid removal.

Polyelectrolyte Hydrogels for Tissue Engineering and Regenerative Medicine.

Polyelectrolyte hydrogels are emerging materials for tissue engineering and regenerative medicine applications due to their tunable biochemical properties, electrical conductivity, biocompatibility and similar network structure to the extracellular matrix in mammalian bodies. In this review, representative polyelectrolyte hydrogels carrying anionic, cationic, ampholytic, zwitterionic and ionic liquid moieties are systemically cataloged to express their chemical structures and preparation strategies. Recent advance of polyelectrolyte hydrogels in tissue engineering and regenerative medicine for drug delivery, skin healing, bone regeneration, cardiac tissue repair and anti-biofouling coating are also highlighted. Eventually, the outlook and challenges of polyelectrolyte hydrogels and their biomedical material applications are also discussed to offer future directions.

Facile synthesis of the encapsulation of Co-based multimetallic alloys/oxide nanoparticles nirtogen-doped carbon nanotubes as electrocatalysts for the HER/OER

The pivotal challenge of electrocatalysis remains the development of highly effective electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this work, a universal strategy of preparing the encapsulation of Co-based multimetallic alloys/oxide nanoparticles in nitrogen-doped carbon nanotubes (named CoM@CNTs, M = Ni/Mn/Fe) was induced by annealing mixtures of the as-synthesized precursor, ethanol and different metallic acetates, including binary CoNi@CNTs, ternary CoNi/MnO@CNTs and quaternary CoNiFe/MnO@CNTs. By virtue of its unique structure with a high electrical conductive network based on CNT substrates, abundant catalytic active sites supplied by multimetallic nanoparticles and protection against nanoparticle corrosion by N-doped carbon layers, the as-synthesized CoNiFe/MnO@CNTs electrocatalyst has remarkable HER properties with a low overpotential of 122 mV and OER activity with a low overpotential of 275 mV at 10 mA cm−2 and excellent stability and durability under long-term testing in alkaline solutions. Therefore, this strategy will provide a new route for fabricating multimetallic-based CNTs as HER/OER electrocatalysts with excellent stability and high catalytic activity.

Superior electromagnetic interference shielding effectiveness of functionalized MWCNTs filled flexible thermoplastic polymer nanocomposites

Carbon nanotubes (CNTs) impart great multi-functionality when reinforced with a polymer matrix. This paper shows the qualitative and quantitative improvements of the mechanical, electrical, and electromagnetic interference shielding effectiveness properties with the additions of the multiwalled carbon nanotubes (MWCNTs) and functionalized MWCNTs (FMWCNTs) in ethylene methyl acrylate (EMA) polymer. Mechanical characterization is performed through tensile testing, and electromagnetic interference shielding effectiveness (EMI SE) is calculated from the scattering parameters obtained from the vector network analyzer. Both properties improve compared to neat polymer with the reinforcement loadings up to a critical value, from where the properties start to degrade due to the agglomeration of the CNTs. FMWCNTs provide better performance in terms of properties over the MWCNT reinforced nanocomposites. Morphological characterization using a scanning electron microscope justifies a lower percolation threshold of FMWCNT/EMA composite by better electrical conductive network formation. At 10 wt% of FMWCNT loading, the FMWCNT/EMA composite shows 25.1 dB of EMI shielding efficiency combined with excellent mechanical and electrical properties extending its potential use in both industry and academia as an excellent flexible EMI shielding material.

An interconnected and scalable hollow Si-C nanospheres/graphite composite for high-performance lithium-ion batteries

Silicon (Si) anode is the most promising alternative for next generation lithium-ion batteries (LIBs) owing to large theoretical capacity, low working voltage and abundant natural resources. However, tremendous volume change of Si during the (de)lithiation processes causes repetitive formation of solid electrolyte interphase (SEI) layers, loss of electrical contact and electrodes pulverization, limiting its commercial application. Herein, we fabricate an interconnected hollow Si-C nanospheres/graphite composite via a facile and scalable approach. Notably, hollow Si-C nanospheres and graphite are homogeneously combined by using the surfactants as surface modifiers of graphite and introducing carbon dioxide (CO2) into magnesiothermic reduction reaction, resulting in the enhanced compatibility between hollow Si-C nanospheres and graphite, and the well-established electrical conductive network. The resultant Si-C nanospheres/graphite composite anode with carbon content of 59 wt% delivers a large reversible specific capacity of 662 mAh g−1 and a high capacity retention of 65.7% at 0.5 A g−1 after 200 cycles. Such excellent rate performance and superior cycling performance are attributed to high electrical conductivity and buffering effect of graphite, superior compatibility between hollow Si-C spheres and graphite, uniform distribution of both Si-C nanospheres with a unique hollow architecture and graphite flakes inside the composites and well-established interconnected electrical conductive carbon networks, which can effectively alleviate Si volume expansion and maintain good electrical contact during cycling. This strategy provides insights into designing Si-based anodes for practical LIBs.

Vanadium disulfide-coated carbon nanotube film as an interlayer for high-performance lithium‑sulfur batteries

Owing to the “shuttle effect” and slow solid–solid reaction of Li2S2–Li2S, the capacity of lithium‑sulfur batteries cannot be fully actualized, and the capacity loss is rapid. To address this issue, in this study, a vanadium disulfide-coated carbon nanotube film (VS2@CNTF), fabricated using floating catalyst chemical vapor deposition following a hydrothermal reaction, was adopted as the interlayer in the sulfur cathode. The initial discharge capacity of the Li-S battery with the VS2@CNTF interlayer was 1432.9 mA·h·g−1 at 0.2 C, which was 85.6% of the theoretical capacity of sulfur. Even at a sulfur loading of 3.6 mg cm−2, the Li-S battery with a VS2@CNTF interlayer demonstrated a discharge capacity of 970.6 mA·h·g−1 after 200 cycles at 1 C. This outstanding performance of the sulfur cathode is partially attributed to the three-dimensional electrical conductive networks formed by the ultra-long intertwined carbon nanotubes, which facilitate the effective adsorption of lithium polysulfides by the VS2@CNTF interlayer, inhibiting the “shuttle effect.” Furthermore, VS2@CNTF catalyzed the solid–solid reaction of Li2S2–Li2S to accelerate the reaction kinetics, thereby enhancing the rate performance.

Superior EMI shielding effectiveness with enhanced electrical conductivity at low percolation threshold of flexible novel ethylene methyl acrylate/single‐walled carbon nanotube nanocomposites

AbstractThe rising trend of electromagnetic pollution has motivated us to develop a novel electromagnetic interference shielding (EMI) material by adopting a facile, industry viable, and cost‐effective solution mixing strategy. Single‐walled carbon nanotubes (SWCNT) as conductive fillers is employed in a lightweight, highly flexible ethylene methyl acrylate (EMA) polymer to fabricate the superior electrically conductive and efficient EMI shielding material at a relatively lower percolation threshold limit compared to other carbonaceous fillers has been justified by their morphological characterization. The electrical conductive network formation is attained at just 1.96 wt% of SWCNT loading resulting in more than 20 dB of EMI shielding effectiveness (EMI SE) dominated by absorption mechanism to fulfill the industrial requirement along with excellent mechanical properties improvement, and the highest SE is 45 dB at 15 wt% of reinforcement facilitating their potential use in both industry and academia.