Conductive Skeleton Research Articles

Honeycomb-like porous copper with pleated surface for supporting phase change material with enhanced thermal conductivity and solar thermal storage performance

Paraffin wax (PW) is concerned in the field of thermal storage because of its high thermal storage density, but it generally has problems such as low thermal conductivity, poor shape stability, and low solar absorption, which limit its application in solar thermal storage and thermal management. In this study, a honeycomb-like 3D porous Cu skeleton with a pleated surface was prepared by the salt template method, and the phase change composites (PCCs) were prepared using this 3D thermal conductive skeleton to support PW. The honeycomb-like porous structure with pleated surface has positive effects on the shape stability and solar-thermal conversion of PW. The thermal conductivity, leakage resistance, and solar-thermal conversion efficiency of the PCCs were significantly improved. Among them, the thermal conductivity of PW@PSHCPC2 reached 3.3 Wm−1 K−1, which was 16.5 times higher than that of PW, and the solar-thermal conversion efficiency reached 89.2 %, and a stable current of 61.8 mA was generated in the solar thermal power generation experiment. These results show that these PCCs have great potential for applications in several fields such as solar thermal storage, waste heat recovery, solar power generation, and electronic thermal management.

Preparation and electrochemical performances for silicon-carbon ternary anode materials with artificial graphite as conductive skeleton

Preparation and electrochemical performances for silicon-carbon ternary anode materials with artificial graphite as conductive skeleton

Space-confined twin-polymerization enabling homogeneous integration of ultrafine TiO2 nanoparticles into a sulfur-doped carbon matrix for boosting lithium storage.

Homogeneous integration of ultrafine TiO2 nanoparticles into a conductive sulfur-doped carbon skeleton was readily crafted by unusual space-confined twin-polymerization of a titanium-containing single-source coupled monomer and subsequent carbonization, producing a robust hetero-architecture for boosting lithium storage with large reversible capacity, high rate capability, and long-term cycling stability.

Ultrafine VN quantum dots modified with a nitrogen-doped reduced graphene oxide anode material for enhanced rate capability and lifespan of lithium-ion batteries

The excellent electrochemistry performance is attributed to vanadium nitride quantum dots (VNQDs) offering large capacity and nitrogen-doped reduced graphene oxide (NrGO) acting as a conductive network and buffer skeleton.

Ultra-stretchable, sensitive and breathable electronic skin based on TPU electrospinning fibrous membrane with microcrack structure for human motion monitoring and self-powered application

With the rapid development of wearable electronic, electronic skin with excellent performance for human motion detection have been widely investigated recently. In this work, a multifunctional electronic skin with three-dimensional conductive network skeleton was prepared based on synergistic conductive filler (carboxylated multi-walled carbon nanotubes (C-MWCNT) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS)) decorated breathable thermoplastic polyurethane (TPU) electrospinning fibrous membrane. Then, microcrack structure was constructed via pre-stretching and the strain sensitivity of the resultant C-MWCNT/PEDOT:PSS/TPU (CPT) conductive fibrous membrane could be effectively adjusted by changing the microcrack density. Due to the three-dimensional conductive network skeleton, microcrack structure and the bridging effect of C-MWCNT between the adjacent crack fragments, ethylene glycol treated CPT (mass ratio of C-MWCNT and PEDOT:PSS is 9/1) (e-CPT9/1) strain sensor exhibited high sensitivity (6008.3), wide response range (680 %), fast response/recovery time (200 ms/200 ms), low detection limit (0.5 %), excellent durability and repeatability (6000 cycles). The excellent strain sensing performances enables it to accurately monitor motion activities and physiological signals, and can also be used as a smart sensing glove to identify different letters gesture and numeric gestures. Furthermore, owing to the photothermal conversion ability and thermoelectric effect of C-MWCNT and PEDOT:PSS, the obtained e-CPT9/1 device also displayed efficient “light-thermal-electric” conversion ability and showed the great potential as self-powered strain sensor.

Synthesis of nanoscale LiCoPO4/C between few-layer graphene and its influence on electrochemical performance for lithium-ion batteries

In this study, the composite cathode material of LiCoPO4/C and graphene is synthesized using solvothermal method assisted by oleylamine. The effect of graphene addition on the material properties is fully investigated, and the synergistic effect of amorphous carbon and graphene is also studied. Graphene serves as a conductive skeleton and provides abundant diffusion paths for electrons. The nanoscale LiCoPO4 material synthesized by solvothermal method is evenly distributed around the few-layer graphene with the assistance of oleylamine, and the amorphous carbon formed after the pyrolysis of oleylamine at high temperature tightly connects LiCoPO4 to the graphene, which improves the conductivity and electrochemical performance of the sample. The results of characterization reveal that adding graphene can prepare LiCoPO4 materials with good crystallization and improve the specific surface area and pore size of the material. At the same time, the amorphous carbon and graphene inside the material also show a good degree of graphitization. Electrochemical test results show that doping graphene with a mass ratio of 6% can enhance the electrochemical performance and cycle stability of LCPC-6%G sample. The initial discharge capacity of LCPC-6%G sample reaches 157.2 mA h g−1 at 0.1 C. In this study, nanoscale LiCoPO4 samples are successfully synthesized on the surface of graphene, which provides a new idea for the preparation of nanoelectrode materials and conductive skeleton composite samples.

Constructing 1D/2D NiCo‐LDH Nanowire/MXene Composites for Efficient And Stable Lithium Storage

AbstractBimetallic layered double hydroxide (LDH) delivers competitive performance in lithium‐ion battery (LIB) because of the unique layered structure. However, the electrochemical performance of LDH is hindered by the low conductivity and the huge structure change upon cycling. To face this challenge, the 1D/2D NiCo‐LDH nanowire/MXene composites (NiCo‐LDH/MXene) are dedicatedly constructed via a simple one‐step hydrothermal method. Owing to the robust conductive skeleton is enabled by MXene nanosheets and abundant electroactive sites provided by NiCo‐LDH nanowires, the NiCo‐LDH/MXene anode exhibits rapid ion diffusion, exceptional redox reaction, and superior structural stability. Consequently, it offers a high specific capacitance of 1081 mAh g−1 after 100 cycles at the current density of 100 mA g−1 and impressive rate performance, i.e., 439 mAh g−1 at the current density of 1000 mA g−1. These results will motivate the exploration of advanced electrode materials for application in energy storage devices.

Emerging Solutions to Enable the Efficient Use of Sodium Metal Anodes: Progress and Perspectives

AbstractSodium‐metal batteries (SMBs) are regarded as key for next‐generation energy storage due to their high theoretical energy and potential cost‐effectiveness. However, Na‐metal systems remain challenged by several factors, including uncontrollable metallic dendrite growth for liquid systems and unstable solid electrolyte interphase (SEI) with most organic electrolytes, which limit the feasibility of SMBs. Here, the authors detail the interrelated degradation mechanisms. Afterward, the recent advances in improving the electrochemical performance of SMBs are highlighted. The strategies can be subdivided into the following taxonomy: The utilization of three‐dimensional (3D) conductive skeletons; the introduction of protective layers; the development of compatible electrolyte systems; and the employment of alloy anodes. Designing deposition substrates for the “‘hostless”’ Na has a great effect on reducing the current density and buffering the plating‐stripping volume expansion. The artificial interface approach would introduce efficient mechanical modulus or film‐forming type barriers, which can inhibit detrimental parasitic reactions. Improved solvent‐electrolyte combinations and additives tailored for Na will promise to suppress Na dendrite growth by obtaining a more stable SEI. The formation of alloy phase with Na can tune the bulk properties of the metal per se. Finally, the research challenges and possible development directions of SMBs are also discussed.

Enhancing the cycling stability of Li-S batteries with flexible freestanding sulfur cathodes through a spider-hunting strategy

Flexible, high-capacity, and long-lasting freestanding sulfur cathodes are essential for developing advanced lithium-sulfur (Li-S) batteries in next-generation flexible electronic devices. However, the severe shuttle effect of lithium polysulfides (LiPSs) hinders their potential applications. This work introduces a flexible freestanding MX-CPNTs-CNTs@NS cathode for Li-S batteries by utilizing a spider-hunting strategy. In this strategy, carbonized polypyrrole nanotubes (CPNTs) and carbon nanotubes (CNTs) intertwine to form a 3D flexible and conductive spiderweb-like skeleton. The incorporation of MXene nanosheets as a function of spiders enables the regulation of a rich hierarchical porous structure. Additionally, the polar terminal functional groups of MXene nanosheets and the pyridinic N of CPNTs contribute to the chemical adsorption and electrocatalysis of LiPSs. The synergistic effect of physical and chemical inhibition strategies results in stable electrochemical performance, including a high specific capacity of 1203.2 mAh/g at 0.1C, and extended cycling stability of 739.6 mAh/g at 1C after 500 cycles (low decay rate of 0.036%). The excellent flexibility, specific capacity, and cycling stability make the freestanding MX-CPNTs-CNTs@NS cathode promising for high-performance flexible electronic devices.

Orderly arranged three-dimensional porous S/Ti3C2/NC potassiphilic scaffold enabling dendrite-free K metal deposition for potassium metal batteries

Potassium (K) metal battery is a promising future electrochemical energy storage system owing to the low electrochemical potential, high theoretical specific capacity, and inexhaustible K resources. However, the K metal anodes prematurely defeat due to the inescapable dendrites growth and volume variation, which severely hindered the practical application of K metal battery. To tackle these issues, we propose a S-modified Ti3C2-chitosan aerogel (S-TNC) with orderly arranged 3D porous structure and high potassiphilicity to construct K metal anode (S-TNC@K) by molten infusing with K metal. S-TNC scaffold buffers the internal volume variation via large porous voids during the plating/stripping, and accelerates electron/ion transport by interconnected conductive skeleton, inducing uniform K deposition. The monodispersed S and N sites in S-TNC improve the potassiphilicity of scaffold, reducing K nucleation barrier and inhibiting K dendrites growth. Benefiting from the above outstanding properties of S-TNC scaffold, the S-TNC@K//PTCDA full battery realizes excellent cycling stability with a boosted specific capacity of 90.2 mA h g−1 after 100 cycles at 1 C. This work solves the dendrites growth and volume variation problems in K metal batteries, which laid foundation for the further development of K metal battery.

MXene-Integrated Perylene Anode with Ultra-Stable and Fast Ammonium-Ion Storage for Aqueous Micro Batteries.

The aqueous micro batteries (AMBs) are expected to be one of the most promising micro energy storage devices for its safe operation and cost-effectiveness. However, the performance of the AMBs is not satisfactory, which is attributed to strong interaction between metal ions and the electrode materials. Here, the first AMBs are developed with NH4 + as charge carrier. More importantly, to solve the low conductivity and the dissolution during the NH4 + intercalation/extraction problem of perylene material represented by perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), the Ti3 C2 Tx MXene with high conductivity and polar surface terminals is introduced as a conductive skeleton (PTCDA/Ti3 C2 Tx MXene). Benefitting from this, the PTCDA/Ti3 C2 Tx MXene electrodes exhibit ultra-high cycle life and rate capability (74.31% after 10000 galvanostatic chargedischarge (GCD) cycles, and 91.67 mAh g-1 at 15.0 A g-1 , i.e., capacity retention of 45.2% for a 30-fold increase in current density). More significantly, the AMBs with NH4 + as charge carrier and PTCDA/Ti3 C2 Tx MXene anode provide excellent energy density and power density, cycle life, and flexibility. This work will provide strategy for the development of NH4 + storage materials and the design of AMBs.

Uniform Co9S8 nanosheets on carbon nanotube arrays grown on Ni mesh as free-standing electrodes for asymmetric supercapacitors

A free-standing 3D core/shell composite material CNTs@Co9S8 on nickel mesh has been prepared by a simple two-step method. Carbon nanotubes (CNTs) grown vertically on the surface of nickel mesh by chemical vapor deposition (CVD) method act as conductive skeleton. Then Co9S8 nanosheets uniformly aligned on the surface of the CNTs by solvothermal method are interconnected to form a honeycomb structure. Owing to the close contact of the CNTs@Co9S8 hybrid with the nickel mesh and the hierarchical 3D porous structure, the prepared Ni@CNTs@Co9S8 electrodes exhibit low resistance and excellent charge storage capability with a specific capacitance of 1305.4 F g−1 at 1 A g−1. The composite delivers an excellent rate capability with 84.3 % capacitance retention at 10 A g−1. An asymmetric supercapacitor composed of Ni@CNTs@Co9S8 and nitrogen-doped carbon nanotubes (NCNTs) shows an energy density of 23.8 Wh kg−1 and a high power density of 8007.4 W kg−1. The specific capacitance of the ASC device remained 87.31 % after 10,000 charge-discharge cycles and two tandem ASCs can power two red LED diodes for at least 7 min, suggesting the potential application of the obtained free-standing electrode for supercapacitors.

Highly conductive diamond skeleton reinforced Cu-matrix composites for high-efficiency thermal management

The weak interfacial bonding strength between diamond and copper intrinsically restricts the enhancement of the thermal conductivity of diamond particles/copper composites (abbreviated as DP/Cu). This work first proposed the diamond skeleton (DS) as the reinforcement element rather than dispersed diamond particles. The tungsten (W) transition layer (c.a. ∼300 nm thick) having adequate thermal expansion coefficient was sputtered onto the surface of DS via vacuum evaporation technology, aiming to improve the wettability between diamond and copper and accordingly increase the thermal conductivity of DS/copper composites extruded by gas pressure infiltration technique. The experimental results show that the coated W layer can effectively improve the wettability of the diamond surface and reduce the wettability angle from 108.6° to 13.2°. Raman and XRD spectra show that the W layer can, to a great extent, prevent the graphitization of the diamond surface. SEM and EDX evidence a continuous heat transfer path of DS inside the composites. The thermal conductivity of the DS/Cu composite with low diamond loading of 18.4 vol% reaches 575 W/mK, 43.3% higher than that of pure Cu. Finite element simulations show that DS exhibits excellent heat transfer characteristics, agreeing well with the thermal conductivity simulation results.

Room-Temperature Synthesis of Carbon-Nanotube-Interconnected Amorphous NiFe-Layered Double Hydroxides for Boosting Oxygen Evolution Reaction.

The oxygen evolution reaction (OER) is a key half-reaction in electrocatalytic water splitting. Large-scale water electrolysis is hampered by commercial noble-metal-based OER electrocatalysts owing to their high cost. To address these issues, we present a facile, one-pot, room-temperature co-precipitation approach to quickly synthesize carbon-nanotube-interconnected amorphous NiFe-layered double hydroxides (NiFe-LDH@CNT) as cost-effective, efficient, and stable OER electrocatalysts. The hybrid catalyst NiFe-LDH@CNT delivered outstanding OER activity with a low onset overpotential of 255 mV and a small Tafel slope of 51.36 mV dec-1, as well as outstanding long-term stability. The high catalytic capability of NiFe-LDH@CNT is associated with the synergistic effects of its room-temperature synthesized amorphous structure, bi-metallic modulation, and conductive CNT skeleton. The room-temperature synthesis can not only offer economic feasibility, but can also allow amorphous NiFe-LDH to be obtained without crystalline boundaries, facilitating long-term stability during the OER process. The bi-metallic nature of NiFe-LDH guarantees a modified electronic structure, providing additional catalytic sites. Simultaneously, the highly conductive CNT network fosters a nanoporous structure, facilitating electron transfer and O2 release and enriching catalytic sites. This study introduces an innovative approach to purposefully design nanoarchitecture and easily synthesize amorphous transition-metal-based OER catalysts, ensuring their cost effectiveness, production efficiency, and long-term stability.

RGO/CNTs/PEDOT: PSS ternary composites with enhanced thermoelectric properties

Graphene oxide/ carbon nanotubes (GO/CNTs) aerogels were prepared by adjusting the proportion of GO and CNTs, the corresponding reduced graphene oxide/CNTs (rGO/CNTs) aerogels were obtained by thermal reduction. Then, poly (3,4-ethylenedioxythiophene): polystyrene sulfonic acid (PEDOT: PSS) was compounded with rGO/CNTs aerogels at a mass ratio of 1:1 to prepare rGO/CNTs/PEDOT: PSS (GCP) composites. Structural analyses revealed the strong π-π interaction between rGO/CNTs and PEDOT: PSS, which leads to the formation of ordered regions. Porous structures of rGO/CNTs aerogels act as conductive network skeleton to promote carrier transport in GCP composites, and the electrical conductivity of GCP composites improves effectively. The optimal electrical conductivity and Seebeck coefficient of GCP5 were 1788.11 S cm−1 and 15.87 μV K−1 respectively. The maximum power factor and ZT merit of GCP5 achieved to 45.03 μW m−1 K−2 and 2.65 × 10−2 at room temperature, which was almost 43 and 17 times than that of PEDOT: PSS.

Prussian blue analogues derived magnetic FeCo@GC material as high-performance metallic peroxymonosulfate activators to degrade tetrabromobisphenol A over a wide pH range.

Metal-organic frame (MOF) materials can effectively degrade organic pollutants, whereas the MOF is rapidly hydrolysed in water and has poor stability and low reusability. However, in the current advanced oxidation process (AOP) system, the removal effect of pollutants under alkaline condition is not ideal. In this study, a magnetic composite material derived from MOF was synthesised and used as a new catalyst for rapid degradation of tetrabromobisphenol A (TBBPA). Compared to precarbonisation, FeCo@GC formed a conductive graphite carbon skeleton, retained the complete rhombododecahedron structure, had a larger specific surface area and provided more active sites for peroxymonosulfate (PMS) activation. The target pollutant TBBPA (20 mg/L) was completely degraded within 30 min, and the mineralisation rate reached 40.98% in the FeCo@GC (150 mg/L) and PMS (1 mM) systems, owing to the synergistic interaction between Fe, Co and graphite carbon. The reactive oxygen species (ROS) involved in the reaction were determined to be SO4•-, ·OH, 1O2 and O2•- by electron paramagnetic resonance and free radical scavenging experiments, and the 1O2 played a dominant role. Based on the results of LC-MS analysis results, the main degradation pathways of TBBPA involve three mechanisms: the debromination reaction, hydroxylation and cleavage of the benzene ring. In addition, compared with previous AOP systems, FeCo@GC/PMS overcomes the disadvantage of poor degradation effect of TBPPA under alkaline conditions, has a wide range pH (3-11) application and has the best effect on TBBPA degradation under alkaline conditions. FeCo@GC has an excellent cycle performance, with a removal rate of re-calcined material of 88.52% after five cycles. Therefore, FeCo@GC can be used as a promising and efficient catalyst for removing environmental organic pollutants.

A high thermal conductive composite phase change film for flexible solar/electro-thermal energy conversion

The applications of phase change materials (PCMs) in solar energy utilization, wearable thermal management and electro-thermal energy storage make it urgent to develop flexible PCMs with high thermal conductivity, electrical conductivity, morphological stability, and solar absorption capacity. Herein, we successfully fabricated a flexible multi-functional composite PCM film by adopting interwoven carbonized bamboo fibers (CBF) as the electrical and thermal conductive framework, with the introduction of polyvinylidene fluoride (PVDF) as the binder to enhance strength and flexibility and flexibility and paraffin as the thermal storage material. Besides, the introduction of Ti3C2Tx as a photon capturer and heating molecule further improved the solar-thermal conversion capability. The composite PCM films exhibited considerable flexibility, favorable thermal storage capacity (>103.6 J/g), and excellent long-term cycling stability. The interwoven electrical and thermal conductive skeleton endowed the flexible phase change films with satisfying electro-thermal conversion capacity and improving thermal conductivity, which further resulted in a promising solar-thermal conversion performance and remarkable Joule heating effect. The as-prepared flexible composite PCM films with excellent solar/electro-thermal conversion responses would be suitable smart materials for future wearable thermal management application.

Direct-writing of three-dimensional porous Fe3N/FeS electrode for efficient degradation of organic pollutants in water through Electro-Fenton process

The Electro-Fenton process is getting a rapid development recently as a novel advanced electro-oxidation technology for the removal of organic pollutants from water. In this work, a three-dimensional (3D) porous Fe3N/FeS composite electrode was created from a Fe2(SO4)3-based composite ink by the direct-writing 3D printing technology combined with a high temperature heat treatment under ammonia atmosphere. Fe3N served as the conductive skeleton of the electrode, while FeS could provide Fe2+ to react with in-situ generated H2O2 in the Electro-Fenton process to generate ·OH radicals. Thus, it could eliminate the need of external ferrous ion addition. The 3D porous Fe3N/FeS composite electrode had desired 3D interconnected macro-channels for efficient mass transport and rough rod surfaces to provide more active sites, which resulted in its superior degradation performance on organics than its traditional two-dimensional (2D) plate counterpart. A two-step H2O2 production path was found on the 3D Fe3N/FeS composite electrode, which had been found to possess a faster reaction kinetics. It effectively degraded rhodamine B (RhB) within a wide pH range from ∼3 to ∼ 10, demonstrated stable performances in repeated uses, and had low iron ion leaching, all of which were beneficial for its potential applications. Furthermore, it also demonstrated effective degradation performances on antibiotics of amoxicillin (AMX) and tetracycline hydrochloride (TC-HCl) in both deionized (DI) water and tap water matrixes, indicating its potential to solve the emerging contaminant problem in real water treatment practices.

Holey Graphene/Sulfur Composite Cathodes Via Coupling with Ferroelectric Nanoparticles for Sustainable and High-Capacity Lithium-Sulfur Batteries

Lithium-Sulfur (Li-S) batteries have been considered promising for high energy density batteries to be used in electronic devices, electric vehicles (EV) and aircrafts which are becoming more prevalent. In addition, Li-S batteries have high theoretical capacity of 1,675 mAh/g in comparison to LIBs of 300 mAh/g. Although Li-S batteries are in great demand, their development is still plagued by rapid capacity fading mainly stemming from polysulfide shuttle. To improve the electrochemical performance of the cathode in Li-S batteries, holey graphene (hG) and carbon-based materials are employed. Holey graphene (HG) contains conductive skeletons as electron transfer paths and abundant mesoporous for longitudinal transport of ions. This architecture ensures efficient charge delivery throughout a thick electrode and maximizes electrode utilization, achieving high-rate and high-capacity energy storage. The coupling of a highly polarized ferroelectric nanoparticles materials (FNPs) layer is an approach that can be used to reduce the characteristic polysulfide shuttling in Li-S batteries. This coupling helps to build up an internal electric field and induces macroscopic charge separations on the surface of the cathode of Li-S batteries. The dry compression manufacturing process facilitates bonding between Sulfur and ferroelectric nanoparticles to generate a more stable cathode. In the present report we are presenting preliminary results of cathode having composition S47.5(FNPs)5hG47.5 in terms of structure, surface morphology and electrochemical performance. A reversible capacity of ~1,400 mAh/gs has been achieved with high coulombic efficiencies (> 87%) and low-capacity fading rate of 0.016% per cycle upto 60 cycles. The active sulfur mass loading ranging from 5.72 mgs/cm2 to 7.01 mgs/cm2 allows maximum high areal capacity up to ~10 mAh/cm2 and superior rate capability for 0.2mA/cm2 and 0.5 mA/cm2. These results suggest sustainable and high-yielding Li–S batteries can be obtained for potential commercial applications.

MOF-Derived Nitrogen-Doped Porous Carbon Polyhedrons/Carbon Nanotubes Nanocomposite for High-Performance Lithium-Sulfur Batteries.

Nanocomposites that combine porous materials and a continuous conductive skeleton as a sulfur host can improve the performance of lithium-sulfur (Li-S) batteries. Herein, carbon nanotubes (CNTs) anchoring small-size (~40 nm) N-doped porous carbon polyhedrons (S-NCPs/CNTs) are designed and synthesized via annealing the precursor of zeolitic imidazolate framework-8 grown in situ on CNTs (ZIF-8/CNTs). In the nanocomposite, the S-NCPs serve as an efficient host for immobilizing polysulfides through physical adsorption and chemical bonding, while the interleaved CNT networks offer an efficient charge transport environment. Moreover, the S-NCP/CNT composite with great features of a large specific surface area, high pore volume, and short electronic/ion diffusion depth not only demonstrates a high trapping capacity for soluble lithium polysulfides but also offers an efficient charge/mass transport environment, and an effective buffering of volume changes during charge and discharge. As a result, the Li-S batteries based on a S/S-NCP/CNT cathode deliver a high initial capacity of 1213.8 mAh g-1 at a current rate of 0.2 C and a substantial capacity of 1114.2 mAh g-1 after 100 cycles, corresponding to a high-capacity retention of 91.7%. This approach provides a practical research direction for the design of MOF-derived carbon materials in the application of high-performance Li-S batteries.