Conductive Fibers Research Articles

Conductive electrospun polymer improves stem cell-derived cardiomyocyte function and maturation

Despite numerous efforts to generate mature human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), cells often remain immature, electrically isolated, and may not reflect adult biology. Conductive polymers are attractive candidates to facilitate electrical communication between hPSC-CMs, especially at sub-confluent cell densities or diseased cells lacking cell-cell junctions. Here we electrospun conductive polymers to create a conductive fiber mesh and assess if electrical signal propagation is improved in hPSC-CMs seeded on the mesh network. Matrix characterization indicated fiber structure remained stable over weeks in buffer, scaffold stiffness remained near in vivo cardiac stiffness, and electrical conductivity scaled with conductive polymer concentration. Cells remained adherent and viable on the scaffolds for at least 5 days. Transcriptomic profiling of hPSC-CMs cultured on conductive substrates for 3 days showed upregulation of cardiac and muscle-related genes versus non-conductive fibers. Structural proteins were more organized and calcium handling was improved on conductive substrates, even at sub-confluent cell densities; prolonged culture on conductive scaffolds improved membrane depolarization compared to non-conductive substrates. Taken together, these data suggest that blended, conductive scaffolds are stable, supportive of electrical coupling in hPSC-CMs, and promote maturation, which may improve our ability to model cardiac diseases and develop targeted therapies.

Thermochromic Conductive Fibers with Modifiable Solar Absorption for Personal Thermal Management and Temperature Visualization.

Thermal management textiles provide an energy-efficient strategy for personal thermal comfort by regulating heat flow between the human body and the environment. However, textiles with a single heating or cooling mode cannot realize temperature regulation under dynamic weather. Furthermore, monocolor textiles do not satisfy aesthetic requirements in a garment. Here, we develop a thermochromic (TC) conductive fiber with a coaxial structure composed of a conductive core and thermochromic shell. The TC conductive fiber-woven fabric has the ability of low-energy dynamic thermal management by combining Joule heating and modulation of solar absorption. Compared with commercial white fabrics, TC conductive fabrics exhibit a maximum temperature drop of 2.5 K, while the temperature of colored commercial fabrics is 7.5-16 K higher than that of commercial white fabrics in the hot. In the cold, the combination of Joule heating and the photothermal effect can provide desired thermal comfort for humans. Meanwhile, heat obtained from solar absorption brings the temperature of a fabric to a predetermined level, which saves energy of 625 W/m2 compared to a conductive-fiber-based textile. In addition, TC conductive fabrics with trichromatic evolution provide a sensitive and instant temperature visualization capable of identification of invisible and intense infrared radiation. These results provide another path to expand potential applications of wearable, flexible electronics.

Study on Multi-Pollutant Test and Performance Index Determination of Wet Electrostatic Precipitator

A wet electrostatic precipitator (WESP) is typically installed downstream of wet flue gas desulfurization (WFGD) to remove fine particles and sulfuric acid mists from flue gases in coal-fired power plants. The emission reduction characteristics of multiple pollutants and the energy consumption data of 214 sets of WESPs (94 sets of metal plate WESPs, 111 sets of conductive Fiber Reinforced Plastic WESPs, and 9 sets of flexible plate WESPs) were tested and analyzed, and the results showed that: WESPs had a high removal efficiency on PM, PM2.5, SO3, droplets and Hg, and mostly concentrated in ≥75%, ≥70%, ≥60%, ≥70% and ≥40%, respectively. The outlet pollutant concentrations were mostly concentrated in ≤5 mg/m3, ≤3 mg/m3, ≤5 mg/m3, ≤15 mg/m3 and ≤5 μg/m3, respectively. Specific power consumption and specific water consumption were concentrated in the range of 0.5~2.5 × 10−4 kWh/m3 and ≤10 × 10−6 t/m3. The correlation analysis of multiple pollutant’s removal performance was studied and the quantitative evaluation index requirements of high efficiency WESPs were determined in this paper. The high efficiency indexes of WESPs, such as PM emission concentration, SO3 emission concentration, PM removal efficiency, SO3 removal efficiency, pressure drop, air leakage rate and specific power consumption, were ≤2.50 mg/m3, ≤2.50 mg/m3, ≥90%, ≥85%, ≤200 Pa, ≤0.5% and ≤1.3 × 10−4 kWh/m3, respectively. The high efficiency indexes of specific water consumption for metal plate WESPs and FRP WESPs were ≤2.50 and ≤0.66 × 10−6 t/m3, respectively. This study can provide valuable reference for the following energy conservation and efficiency improvement of ultra-low emission units.

Silicon elastomer as flexible substrate: dielectric characterization and applications for wearable antenna

In this paper, low-cost mold silicone and silicone elastomers are investigated as substrates for the realization of flexible antennas. A methodical dielectric characterization is carried out, followed by a detailed explanation of the manufacturing process of the silicone elastomers. The prepared silicone elastomer substrates are also subjected to mechanical tests to ensure flexibility and robustness. The mechanical tests corroborated the utilization of the prepared silicone elastomers for the flexible antennas. Silicone has limited adhesion to metal, so when producing a silicone substrate, a 0.5 mm deep cavity is created with a negative impression of the intended metal component. Consequently, the metal layer is embedded within the silicon substrate, aligning the top surface of the metal flush with the silicone substrate edges. The radio frequency (RF) structure incorporates ridges within the silicone substrate to form a gap, effectively securing the metal on the surface of the silicone. Finally, to prevent the metal from falling from the silicone substrate, Kapton tape is laminated on the substrate. The wrapping of the Kapton tape additionally provides protection from moisture since the silicone elastomer substrate is prone to moisture absorption. The proposed technique is experimentally verified by designing and prototyping a coplanar patch antenna using copper and conductive woven fiber on the silicone substrate. The simulation analysis and experimentation results authenticated the effectiveness of the proposed technique to design a flexible antenna on the silicone elastomer substrates. It is also concluded that the conductive woven fiber-based prototype offers higher flexibility as compared to the copper-based prototype. It is also clinched that there exists a trade-off in flexibility and performance characteristics due to the conductivity and texture difference between the copper and conductive woven fiber.

All-Fabric Capacitive Pressure Sensors with Piezoelectric Nanofibers for Wearable Electronics and Robotic Sensing.

Flexible pressure sensors are increasingly sought after for applications ranging from physiological signal monitoring to robotic sensing; however, the challenges associated with fabricating highly sensitive, comfortable, and cost-effective sensors remain formidable. This study presents a high-performance, all-fabric capacitive pressure sensor (AFCPS) that incorporates piezoelectric nanofibers. Through the meticulous optimization of conductive fiber electrodes and P(VDF-TrFE) nanofiber dielectric layers, the AFCPS exhibits exceptional attributes such as high sensitivity (4.05 kPa-1), an ultralow detection limit (0.6 Pa), an extensive detection range (∼100 kPa), rapid response time (<26 ms), and robust stability (>14,000 cycles). The sensor's porous structure enhances its compressibility, while its piezoelectric properties expedite charge separation, thereby increasing the interface capacitance and augmenting overall performance. These features are elucidated further through multiphysical field-coupling simulations and experimental testing. Owing to its comprehensive superior performance, the AFCPS has demonstrated its efficacy in monitoring human activity and physiological signals, as well as in discerning soft robotic grasping movements. Additionally, we have successfully implemented multiple AFCPS units as pressure sensor arrays to ascertain spatial pressure distribution and enable intelligent robotic gripping. Our research underscores the promising potential of the AFCPS device in wearable electronics and robotic sensing, thereby contributing significantly to the advancement of high-performance fabric-based sensors.

Thermal Interface Engineering in a 3D-Structured Carbon Framework for a Phase-Change Composite with High Thermal Conductivity.

Phase-change materials (PCMs) are promising thermal storage medium for thermal management due to their efficient thermal energy harvesting capabilities. However, the low thermal conductivity (TC) and poor shape stability of PCMs have hindered their practical applications. Construction of an interconnected three-dimensional (3D) heat-conductive structure is an effective way to build phonon conduits and provide PCM confinement. Phonon scattering at the interface is an unavoidable effect that undermines the TC improvement in the PCM composite and necessitates careful engineering. This study focuses on creating a highly thermally conductive 3D carbon-bonded graphite fiber (CBGF) network to enhance the TC of the PCM, with attention especially on thermal interface engineering considering both filler-matrix (F-M) and filler-filler (F-F) interfaces. The composite with an optimized proportion of F-M and F-F interface area achieves the highest TC of 45.48 W·m-1·K-1, which is 188.5 times higher than that of the pure PCM, and a high TC enhancement per volume fraction of the filler (TCEF) of 831% per 1 vol % loading. This also results in an enhanced spatial construction for PCM confinement during the phase change. The results emphasize the significance of interface engineering in creating high-TC and form-stable phase-change composites, providing insightful guidance for rational structural design.

Design, preparation, and performance research of a knitted sensor for respiratory rate detection

Owing to flexible, good wearing comfort and fitting the human body well, flexible knitted sensors can play a significant role in monitoring respiratory signals, an important auxiliary diagnostic information. We proposed an idea that underwear is equipped with flexible sensors to realize respiratory signal detection by daily underwear. Four conductive fibers were used to knit jersey stitches and ribs to produce eight knitted flexible sensor samples. We explored flexible knitted sensors' design and preparation first. Considering the influence of production and daily cleaning on durability, we tested conductive properties, an essential property for sensors before and after heat setting and multi-wash tests. Meanwhile, practical application was tested. The results prove that the most suitable raw materials and knitting structure are 111dtex silver-plated yarn and jersey stitch. Because the sensor fabricated by 111dtex silver-plated yarn has better durability. Washing can optimize its conductivity and the conductivity of sensors fabricated by other conductive yarn is worse than that after washing. Then, the amounts of courses can influence conductivity greatly. Under the same condition, more courses mean better conductivity and durability after washing. Meanwhile, the heat setting temperature can be selected as 100–120 ℃. Because this temperature can promote the conductive properties of most sensors. At last, practical applications prove the feasibility of sensors. There is only a slight gap between the tested by sensors and the actual value. This paper can guide the design of flexible knitting sensors for raw materials and structure. What’s more, it is meaningful for the thermal setting process in the actual production process of the factory. Last but not least, the underwear equipped with sensors based on integrated weaving can detect respiratory frequency accurately. This will make a significant difference in medicine.

Low-temperature sintering of silver-ammonia complex organic composite ink shows high conductivity for humidity sensors

The development of flexible electronic devices is faced with the challenge of difficult fabrication of complex functional structures on flexible substrates. In this paper, a high viscosity ink of silver-ammonia complex was developed based on the reductive ink principle. Using the electrohydrodynamic direct writing, composite fiber patterned printing was achieved on a flexible substrate. By low-temperature sintering of precursor fibers for reduction, a dense silver structure was formed on the surface, resulting in the formation of Ag/PEO conductive fibers. This approach avoided the high temperature damage to the flexible substrate and the adhesion of materials, while demonstrating good conductivity. The Ag/PEO conductive fibers exhibited different sensitivities to H2O molecules in low, medium, and high humidity environments, which were used to design a flexible Ag structure humidity sensor (ASHS) as a functional material. The ASHS showed a linear response relationship and a fast response speed in an environmental humidity range of 11 % to 75 %RH, enabling real-time monitoring of human respiration. This study demonstrates a promising application prospect of the silver-ammine complex ink in the field of flexible electronic devices.

Template-Free and Stretchable Conductive Fiber with a Built-In Helical Structure for Strain-Insensitive Signal Transmission.

With the rapid development of intelligent electronic devices, conductive fibers have become very critical to signal transmission devices. However, metal-based rigid conductive wires, such as high-modulus copper and silver wires, are prone to signal failure owing to tensile breakage under large strain conditions. Therefore, strain-insensitive stretchable conductive fibers for signal transmission are critical for next-generation wearable devices. Herein, a stretchable conductive fiber with a built-in helical structure is constructed by a "speed discrepancy" fiber-coating strategy with mass scalable production (60 cm/min). Such a "speed discrepancy" strategy is the key mechanism to template-free fabricate a built-in helical structure of the stretchable conductive fiber. The resultant fiber exhibits high conductivity (873 S/cm), stable insensitive signal transmission with a high quality factor (47.4), and a low relative resistance change (∼6%) under large strain. The built-in helical structure inspired by loofah whiskers endows the fiber with excellent strain insensitivity, and it can withstand large strains. On the proof of concept, our fiber can be seamlessly knitted, woven, and braided into smart textiles as an ideal signal transmission device under large strains, which will undoubtedly promote the development of intelligent electronic textiles and next-generation wearable devices.

Thermal Conductivity and Microstructure of Novel Flaxseed-Gum-Filled Epoxy Resin Biocomposite: Analytical Models and X-ray Computed Tomography.

The growing awareness of the environment and sustainable development has prompted the search for solutions involving the development of bio-based composite materials for insulating applications, offering an alternative to traditional synthetic materials such as glass- and carbon-reinforced composites. In this study, we investigate the thermal and microstructural properties of new biocomposite insulating materials derived from flaxseed-gum-filled epoxy, with and without the inclusion of reinforced flax fibers. A theoretical approach is proposed to estimate the thermal conductivity, while the composite's microstructure is characterized using X-ray Computed Tomography and image analysis. The local thermal conductivity of the flax fibers and the flaxseed gum matrix is identified by using effective thermal conductivity measurements and analytical models. This study provides valuable insight into the thermal behavior of these biocomposites with varying compositions of flaxseed gum and epoxy resin. The results obtained could not only contribute to a better understanding the thermal properties of these materials but are also of significant interest for advanced numerical modeling applications.

The effect of conductive aligned fibers in an injectable hydrogel on nerve tissue regeneration

Injectable hydrogels are a promising treatment option for nervous system injuries due to the difficulty to replace lost cells and nervous factors but research on injectable conductive hydrogels is limited and these scaffolds have poor electromechanical properties. This study developed a chitosan/beta-glycerophosphate/salt hydrogel and added conductive aligned nanofibers (polycaprolactone/gelatin/single-wall carbon nanotube (SWCNT)) for the first time and inspired by natural nerve tissue to improve their biochemical and biophysical properties. The results showed that the degradation rate of hydrogels is proportional to the regrowth of axons and these hydrogels’ mechanical (hydrogels without nanofibers or SWCNTs and hydrogels containing these additions have the same Young's modulus as the brain and spinal cord or peripheral nerves, respectively) and electrical properties, and the interconnective structure of the scaffolds have the ability to support cells.

Shear strength, wear, thermal conductivity, and hydrophobicity behavior of fox millet husk biosilica and Amaranthus dubius stem fiber–reinforced epoxy composite: a concept of biomass conversion

Shear strength, wear, thermal conductivity, and hydrophobicity behavior of fox millet husk biosilica and Amaranthus dubius stem fiber–reinforced epoxy composite: a concept of biomass conversion

Electromyographic signature of isometric squat in the highest refuge in Europe.

Reports of electromyography during hypoxic exercise are contrasting, due to protocol and muscle diversity. This work aimed to investigate alterations in muscle activation and myoelectrical fatigue during exercise at high-altitude in those muscles primarily involved in trekking. Twelve young adults balanced by gender and age were tested at low (1,667 m) and high (4,554 m, "Capanna Margherita", Italy) altitude, during an isometric squat lasting 60 seconds. High-density surface electromyography was performed from the quadriceps of right limb. The root mean square (RMS), median frequency with its slope, and muscle fiber conduction velocity (MFCV) were computed. Neither males nor females showed changes in median frequency (Med: 36.13 vs 35.63 Hz) and its slope (Med: -9 vs -12 degree) in response to high-altitude trekking, despite a great inter-individual heterogeneity, nor differences were found for MFCV. RMS was not significantly equivalent, with greater values at low altitude (0.385 ± 0.104 mV) than high altitude (0.346 ± 0.090 mV). Unexpected results can be due either to a postural compensation of the whole body compensating for a relatively greater effort or to the inability to support muscle activation after repeated physical efforts. Interesting results may emerge by measuring simultaneously electromyography, muscle oxygenation and kinematics comparing trekking at normoxia vs hypoxia.

The strategic use of hyperbranched polyamidoamine through chemical bonding in fabricating stable, highly conductive Ag-plated aramid fiber

High-performance conductive aramid fibers (PPTA) can be applied in many fields, while the poor interface compatibility between aramid fiber and conductive element restricted their practical applications. Herein, PPTA-based conductive fiber were fabricated by firstly functionalizing the PPTA surface to covalently attach some hyperbranched polyamidoamine (HPAMAM), then coating the crosslinked HPAMAM to constructing cross-linked HPAMAM interface. The stable cross-linked HPAMAM interface was constructed creatively by chemical method and it strongly strengthened interfacial bonding between Ag plated layer and PPTA. Meanwhile, the excellent mechanical property of PPTA was maintained, as the tensile strength of Ag-plated PPTA only had lowed 0.25 cN/dT compared to the original PPTA. The electrical resistance of prepared Ag-plated PPTA exhibited a very low value of 0.043 Ω/cm. Moreover, the silver-plated PPTA presented high washing fastness that the resistance merely increased from 0.043 to 0.33 Ω/cm after 6 cycles of washing. This research demonstrates a novelty and efficient path to fabricate high performance conductive aramid fiber, which perfectly retained mechanical properties of the fibers.

Nano GeSe2/C anchored in carbon sponge skeleton for free-standing flexible lithium-ion battery electrodes

As a typical conversion alloyed anode material, Germanium selenide (GeSe2) exhibits isotropic lithiation behavior and high theoretical charge-discharge specific capacity. However, pure GeSe2 anode faces significant volume expansion (∼250 %−360 %) and further exploration is needed in the preparation of flexible electrode materials and structural design. Herein, a simple strategy is designed to load GeSe2/C-2 nanoparticles with porous carbon-coated structure on a flexible cross-networking substrate. The 3D network substrate is composed of highly conductive carbon nanotubes and adhesive cotton cellulose fibers. A two-step method involving coating and cross-linking is designed to achieve the fabrication of self-supporting flexible electrodes. As an anode for LIBs, the one layer GeSe2 discs with ∼0.65 mm thickness manifest capacities of 827.1, 744.4, 676.3, and 472.9 mAh g−1 at 0.1, 0.2, 0.5, and 1 A g−1, respectively. This superior Li+ storage performance can be attributed to the positive collective impact from the integration of nano-scale material, low crystalline properties, and carbon sponge skeleton. Furthermore, the GITT tests indicate that the diffusion coefficient of Li+ in the GeSe2-based electrodes ranged from 10−15 to 10−12 cm2/s, and the thickness of the flexible electrode (including two layers) has a negligible impact on its electrochemical performance.

Melt-blown fiber felt for efficient all-weather recovery of viscous oil spills by Joule heating and photothermal effect

Adsorbents play a vital role in responding to marine oil spills, yet effectively cleaning up viscous oil spills remains a technical challenge. Herein, we present a superhydrophobic oil-adsorbing felt prepared using melt-blown technology and functionally enhanced with a photoelectric composite CNT/PANI coating for effectively cleaning up high-viscosity oil spills. By virtue of its superior solar/Joule heating ability and thermally conductive fiber network, p-CNT/PANI@PP notably reduced crude oil viscosity and enhanced the oil diffusion coefficient within pores. Leveraging primarily solar heating and supplemented by Joule heating, p-CNT/PANI@PP demonstrates an impressive in-situ adsorption rate of up to 560 g/h for ultra-high-viscosity crude oil (c.a. 138000 mPa·s), alongside an adsorption capacity of 15.57 g/g. This measure enables efficient viscosity reduction and continuous day-and-night recovery of viscous crude oil, addressing the challenges posed by seasonal fluctuations in seawater temperature and adverse weather conditions. Moreover, a conveyorized collector integrated with an oil-adsorbing felt realizes continuous recovery of viscous oil spills with speed control to tackle varying thicknesses of oil film. Given the top-down material design, superior functionality, and applicability to applications, this work provides a comprehensive and feasible solution to catastrophic large-area viscous oil spills.

The Influence of Technological Factors and Polar Molecules on the Structure of Fibrillar Matrices Based on Ultrafine Poly-3-hydroxybutyrate Fibers Obtained via Electrospinning

The article examines the regularities of structure formation of ultrafine fibers based on poly-3-hydroxybutyrat under the influence of technological (electrical conductivity, viscosity), molecular (molecular weight), and external factors (low-molecular and nanodispersed substances of different chemical natures). Systems with polar substances are characterized by the presence of intermolecular interactions and the formation of a more perfect crystalline fiber structure. Changes in technological and molecular characteristics affect the fiber formation process, resulting in alterations in the morphology of the nonwoven fabric, fiber geometry, and supramolecular fiber structure. Polymer molecular weight, electrical conductivity, and solution viscosity influence fiber formation and fiber diameter. The fiber structure is heterogeneous, consisting of both crystalline and non-equilibrium amorphous phases. This article shows that with an increase in the molecular weight and concentration of the polymer, the diameter of the fiber increases. At the same time, the increase in the productivity of the electrospinning process does not affect the fiber geometry. The chemical structure of the solvent and the concentration of polar substances play a decisive role in the formation of fibers of even geometry. As the polarity of the solvent increases, the intermolecular interaction with the polar groups of poly-3-hydroxybutyrate increases. As a result of this interaction, the crystallites are improved, and the amorphous phase of the polymer is compacted. The action of polar molecules on the polymer is similar to the action of polar nanoparticles. They increase crystallinity via a nucleation mechanism. This is significant in the development of matrix-fibrillar systems for drug delivery, bioactive substances, antiseptics, tissue engineering constructs, tissue engineering scaffolds, artificial biodegradable implants, sorbents, and other applications.

Electro-mechanical behavior of multi-functional glass fiber composites under dynamic Mode-I fracture loading

An experimental study was performed to investigate damage sensing and fracture toughness of multifunctional conductive glass fiber composites under dynamic mode-I fracture loading. Carbon nanotubes (CNTs) were dispersed within the epoxy matrix using a shear mixing and sonicating process. An electrostatic wet flocking process was used to reinforce milled short PAN-based carbon fibers onto each of the layers of glass fiber fabric along the thickness direction in the composites. These layers of flocked fabric were stacked, and a vacuum infusion process was employed to fabricate the composites. The parametric study consisted of two carbon fiber lengths (80 μm and 150 μm) and two fiber densities (1000 fibers/mm2 and 2000 fibers/mm2) and was performed to investigate the damage sensing capabilities of a three-dimensional conductive network generated through CNTs and carbon fibers. A double cantilever beam (DCB) configuration was considered, and a modified Hopkinson pressure bar setup along with a high-speed camera was used to investigate dynamic fracture toughness of the composites. The piezo-resistance response of the composites during dynamic fracture was measured using a modified system of four probes. For comparison, composites were also characterized for fracture toughness and piezo-resistance under quasi-static fracture loading conditions. The addition of short, milled PAN-based carbon fibers significantly increased the fracture toughness of glass/epoxy composites. The piezo-resistance response of the composites was easily correlated with instances of sudden crack growth during static fracture loading.

Study on Heating Performance and Flexural Strength Properties of Electrically Conductive Mortar

The use of electrically conductive mortar (ECM) is a relatively new construction material technology developed to obtain high conductivity and mechanical strength. This study presents an experimental investigation on the heating performance and flexural strength properties of ECM mixed with carbon fiber (CF) and steel fiber (SF), which are conductive fibers. Furthermore, the internal microstructure of the ECM was analyzed with a scanning electron microscope (SEM) and thermogravimetric analysis was carried out using a thermogravimetric analyzer (TGA) device. The results of the experiment showed that the incorporation of SF had little effect on heating performance. In the case of CF, however, it was found that as the fiber contents and applied voltages increased, the heating performance increased. In particular, the maximum heating temperature of the ECM-CF125 specimen was 145.1 °C at an applied voltage of 30 V and an electrode spacing of 40 mm, which was about 7.3 times higher than the initial temperature (20 °C). In addition, the flexural strength of ECM mixed with SF was higher than that of plain mortar (PM), whereas the ECM-CF125 specimen showed a greater tendency to significantly decrease. It was confirmed that the hydration products and internal microstructures of the specimens were unaffected by repetitive electrical heating, and the ECM maintained stable electrical conductivity.

Design of PGM-Free Cathode Catalyst Layers for PEMFC Applications: The Impact of Electronic Conductivity

The impact of the electronic resistance of platinum-group-metal-free cathode catalyst layers (PGM-free CCLs) for proton-exchange-membrane fuel cells (PEMFCs) was systematically investigated. Here we selected two different PGM-free catalysts (having high and low electronic conductivity) and integrated them into CCLs without and with conductive carbon fiber additives. To investigate the impact of the electronic resistivity () of PGM-free catalysts and CCLs, their through-plane values were quantified by an in situ electrochemical impedance spectroscopy (EIS) approach based on a one-dimensional transmission line model. The results indicate that the electronic conductivity of PGM-free CCLs can be increased by adding carbon additive, resulting in a significant improvement of the fuel cell performance (by ∼60 mV at 1 A cm−2 in H2/O2 configuration). Ex situ four-point probe measurements of the in-plane values of some of the CCLs were found to differ vastly from the through-plane values. This difference is attributed to the anisotropic morphology of the CCLs, caused by preferential fiber orientation and/or cracks in the CCLs. In the end, we suggest guidelines for the design and evaluation of PGM-free CCLs and for assessing and improving their electronic resistance.