Carbon Binder Research Articles

Digital Twin Reveals the Impact of Carbon Binder Domain Distribution on Performance of Lithium‐Ion Battery Cathodes

The rising demand for high‐performance lithium‐ion batteries (LIBs) emphasizes the need for precise electrode design. The carbon binder domain (CBD) within electrodes, crucial for electron transport and structural integrity, can impede lithium‐ion transport and reduce electrochemically active sites. This study leverages digital twin technology to investigate the impact of CBD distribution along the electrode thickness on LIB cathode performance. Virtual LIB cathodes with varying CBD configurations are generated, and their performance using 3D heterogeneous electrochemical modeling is evaluated. The results reveal that a steep CBD gradient significantly diminishes charge capacity compared to a mild gradient, particularly at higher current rates. This reduction is attributed to an increased tortuosity factor and an uneven distribution of electrochemical activity, which adversely affect mass transport and electrochemical reaction dynamics. These effects are more pronounced at lower porosities and higher loading levels. These findings highlight that optimizing CBD distribution is critical for advancing electrode design and enhancing LIB cathode performance.

Direct aqueous mineral carbonation of secondary materials for carbon dioxide storage

Mineral carbonation of secondary materials offers an innovative way of storing carbon dioxide in materials that instead would mostly go to waste. This study investigates the carbonation efficiency (CE) of 11 different secondaries from refractory production, waste incineration, and the paper industry compared to untreated and thermally activated serpentinite. To determine the chemical and mineralogical composition of the materials, various analytical methods, like X-ray fluorescence, X-ray diffraction, scanning electron microscopy, Brunauer-Emmet-Teller and thermogravimetric analysis have been employed, both before and after the direct aqueous carbonation process. Each material was examined over reaction times of 6 & 10 hours at 180 °C and a starting pressure of 20 bar in a 0.6 L stainless steel batch reactor. The received results were then compared to the theoretical CO2 uptake, defined as the maximum carbon dioxide storage potential achievable if all Ca, Fe and Mg ions were converted to carbonates. The findings indicate carbonation efficiencies of 14–65 % for secondary materials, compared to 0.7–14 % observed in the serpentinite samples. The highest uptakes were achieved by the refractory materials, primarily due to their high metal oxide content. However, a negative impact was observed from graphite-based carbon binders in the refractories, with increased leaching of these binders leading to a decrease in carbonation efficiency. Materials with higher SiO2 content showed reduced performance, suggesting a passivation layer buildup during carbonation.

Visualizing and Quantifying Electronic Accessibility in Composite Battery Electrodes using Electrochemical Fluorescent Microscopy

Electronic connections between active material particles and the conductive carbon binder domain govern high-energy commercial Li-ion batteries' rate capability and lifetime (LIB). This work develops an in situ electrochemical fluorescent microscopy (EFM) technique that maps fluorescence intensity to these local electronic connections. Specifically, rapid redox kinetics of an electrofluorophore translates to reaction distributions limited by the electronic accessibility of battery electrode regions and individual active material particles. This technique can visualize hot spots, dead zones, and isolated particles on the electrode surface. EFM characterization of a series of LiNi0.33Mn0.33Co0.33O2 electrodes across processing parameters finds a significant negative correlation between the number of disconnected active particles and the rate capability. This low-cost technique provides quantitative mesoscale characterization of commercial LIB electrodes with fast throughput (<60 s) to facilitate rapid research and development and provide manufacturing quality control.

XCT images-based modeling for elucidating electrochemical inert phase-dependent multiscale electrode kinetic behaviors

The electrochemically inert phase (EIP) within the electrode is formed by the combination of carbon black and binder, characterized by a highly heterogeneous spatial distribution and structural morphology. This heterogeneity impairs electrode performance under varying discharge rates and temperatures. In this study, X-ray computed tomography is employed to image the original electrode. The resulting grayscale images are digitally processed to reveal the two-dimensional (2D) and three-dimensional (3D) features of the EIP morphology, thereby providing a design window to understand the influence of EIP morphology. The physical structure characterization indicates that, compared to bulk-like EIP (B-EIP), film-like EIP (F-EIP) tends to cover the active surface of the active material (AM), exacerbating the heterogeneity of the lithiation reactions within the electrode. The reduction in the AM active surface area correlates the state of lithiation (SOL) of particles with their active specific surface area (αa). At low temperatures, the temperature sensitivity of electrodes intensifies the risk of αa loss, promoting heterogeneous reaction transfer between particles. The Biot number (Bi) is used to evaluate the competing mechanisms between interfacial reactions and bulk diffusion within particles. In electrodes with a high EIP content, the reaction rate at the particle/electrolyte interface is accelerated, causing particle performance to be dominated by interfacial reactions. Finally, the electrochemistry and heat generation from the particle-level to the electrode-level in thicker electrodes are examined. It demonstrates that ion diffusion in the pore controls interfacial reactions and heat transport behavior. Aggregated high-flux reactions and localized hot spots exacerbate the heterogeneous degradation and side reactions within the electrode.

Snapshot on 3D printing with alternative binders and materials: Earth, geopolymers, gypsum and low carbon concrete

The rapid development of 3D concrete printing now offers mechanical efficiency and freedom to push the limits of construction design. The digital manufacturing process holds potential for reducing carbon footprints through design optimization. Printable concrete, which is a mix of cement (based on ordinary Portland cement), aggregates, and admixtures, is attractive due to widespread and cost-effective constituents. However, many common formulations omit gravel, requiring higher cement paste volumes and inducing significant embodied carbon. Assessing the potential of low-carbon cements like Limestone Calcined Clay Cement (LC3), calcium aluminate cement (CAC), or magnesium-based cement for 3D printing is a current challenge that can address this issue. Tailoring these construction materials to printing applications and environmental needs now drives scientific exploration. This paper comprehensively reviews alternative materials and binders such as earthen materials, geopolymers, low carbon binders or gypsum-based materials, addressing fresh and hardened properties, developed digital processes, targeted applications, and discussing advantages and drawbacks of each alternative.

2D Discrete Element Simulation of Electrode Structural Evolutions in Li‐Ion Battery During Drying and Calendering

Drying and calendering are critical steps in the manufacture of electrodes for lithium‐ion battery that affect their mechanical and electrochemical properties. A 2D representative volume element (RVE) model, including active material and carbon binder domain particles of different shapes and sizes, is developed. The evolution of the RVE structure is simulated using the discrete element method, providing insight into changes in velocity, coordination number, porosity, pore size distribution, tortuosity, and stress. Based on this analysis, a three‐step drying scheme is proposed in accordance with the experimental drying results. In addition, the calendering process significantly improves the mechanical integrity and electronic conductivity of the electrode. Through simulations and experimental observations of changes in surface morphology and porosity, an optimal compression ratio of about 20% is determined for the electrode.

Superior sodium storage anode constructed via chemical bonding between S-doped hard carbon and graphene oxide binder

Superior sodium storage anode constructed via chemical bonding between S-doped hard carbon and graphene oxide binder

Ecofriendly K-Ion Batteries Relying on Abundant Chemical Elements and Water-Based Processes

Current Li-ion batteries are mainly composed of a graphite anode and a cathode based on either NMC (LiNixMnyCozO2) or LFP (LiFePO4) materials. However, the rapid growth of the electric car market will generate significant stress on key chemical elements (nickel, cobalt, copper, lithium). Moreover, the production of NMC and LFP materials turns out to be very energy intensive (multiple calcinations) and uses toxic solvents (NMP, ammonia). Because of that, Li-ion batteries are quite expensive and their ecological footprint is relatively high.The scope of our work is to develop a potassium-ion battery which does not require any critical element and whose production significantly reduces the ecological footprint of the system. Such a battery technology could find its place either in low-cost electric cars or in large-scale-energy-storage devices.We focused our efforts on the development of a Prussian White cathode material based on potassium, manganese and iron (K2Mn[Fe(CN)6) showing a theoretical capacity of 155 mAh/g with a potential close to 4 V vs K+/K. The synthesis of this material takes place in water at ambient temperature and it does not involve any calcination. First we optimized the synthesis via a chelating route: tuning the morphology of the Prussian White particles allowed us to come closer to the theoretical capacity of the material. Then we developed water-based coating slurries for our material. We were able to obtain electrodes containing 90 wt% of active material by optimizing both carbon additive and binder. These electrodes showed similar performances compared to electrodes obtained with literature-standard conditions (70 wt% active material, NMP-based slurries). Finally, we tested our Prussian White in full cells versus graphite in coin cells and pouch cells. Figure 1

Visualizing Reaction Distributions for Materials Validation and Failure Analysis in Li-Ion Batteries

A real-time, high-throughput visualization technique for heterogeneity in lithium-ion battery (LIB) electrodes is necessary to understand battery performance on a mechanistic level. Our group, along with others, has seen that battery performance is governed by short range (<20 um) electron transfer between the active material and carbon binder domain (CBD) within electrodes [1]–[3]. Available imaging techniques for visualizing the electronic connectivity of LIB electrodes are limited to nanoscale, single particle resolutions using sophisticated synchrotron X-ray or electron microscopy [4]–[6]. Optical microscopy offers the correct spatial resolution for visualizing the submicron connection of active particles to CBD, but is limited by colorimetry of electrode materials- with graphite being the exception due to its visible color change during lithiation [7]. There is a rapidly growing body of research interested in studying the ionic diffusion pathways of Li-ion using operando optical microscopy, however none currently exist for studying the submicron electronic connectivity through a facile, operando approach- especially under a industrially applicable lens [8]. To the best of our knowledge, this study presents the first spatially- and time- resolved technique for visualizing the electronic connectivity of commercial LIB electrodes using operando electrochemical fluorescent microscopy (EFM). This technique relies on the principle of electrofluorochromism, which we use to our advantage for a simple electrochemical system involving heterogeneous electron transfer. This allows us to use fluorescence as a real-time tracker for electronic heterogeneity, where electronic ‘dead-zones’ present as non-fluorescent regions in 2D images.Using our technique, we visualize commonly used commercial LIB electrodes (carbon content 1-4%, regimented processing), including NMC (LiNixMnyCo1-x-yO2), LFP (LiFePO4), and LCO (LiCoO2) against formulaically similar in-house made LIB electrodes (< 3.5% carbon content) as a proof of concept. We first validate the efficacy of this technique by testing commercial NMC, with a flaked off piece of active material, to show that areas of electronic discontinuities can in fact be represented by non-fluorescence (Fig.1.) We also find that when compared to commercial electrodes, those which are fabricated in house reveal isolated active particles, agglomerated carbon islands, and dead zones, undiscernible by brightfield imaging (Fig. 2.) Global feature extraction is performed on post-processed images to quantify electrode topology and evaluate electronic connectivity of active particles of battery electrodes, as well as heterogeneous mapping to determine the heterogeneity index of electrodes imaged. Testing our technique on low- and high- performing electrodes from an established library of coin-cell data allows for a straightforward way of correlating performance metrics to heterogeneity features. This quick (<1hr), reproducible visualization technique is general enough to be used to study the electronic connectivity of emerging new battery electrodes, as well as verify commercially available ones. Using this approach to verify LIB electrodes prior to assembly could save months to years of battery testing by being used as an alternative to lengthy full cell testing.[1] S. L. Morelly, N. J. Alvarez, and M. H. Tang, “Short-range contacts govern the performance of industry-relevant battery cathodes,” Journal of Power Sources, vol. 387, pp. 49–56, May 2018, doi: 10.1016/j.jpowsour.2018.03.039.[2] R. M. Saraka, S. L. Morelly, M. H. Tang, and N. J. Alvarez, “Correlating Processing Conditions to Short- and Long-Range Order in Coating and Drying Lithium-Ion Batteries,” ACS Appl. Energy Mater., vol. 3, no. 12, pp. 11681–11689, Dec. 2020, doi: 10.1021/acsaem.0c01305.[3] J. Entwistle, R. Ge, K. Pardikar, R. Smith, and D. Cumming, “Carbon binder domain networks and electrical conductivity in lithium-ion battery electrodes: A critical review,” Renewable and Sustainable Energy Reviews, vol. 166, p. 112624, Sep. 2022, doi: 10.1016/j.rser.2022.112624.[4] S. Li et al., “Mutual modulation between surface chemistry and bulk microstructure within secondary particles of nickel-rich layered oxides,” Nat Commun, vol. 11, no. 1, Art. no. 1, Sep. 2020, doi: 10.1038/s41467-020-18278-y.[5] P.-C. Tsai et al., “Single-particle measurements of electrochemical kinetics in NMC and NCA cathodes for Li-ion batteries,” Energy Environ. Sci., vol. 11, no. 4, pp. 860–871, Apr. 2018, doi: 10.1039/C8EE00001H.[6] A. Singer et al., “Nucleation of dislocations and their dynamics in layered oxide cathode materials during battery charging,” Nat Energy, vol. 3, no. 8, Art. no. 8, Aug. 2018, doi: 10.1038/s41560-018-0184-2.[7] Y. Yamagishi, H. Morita, Y. Nomura, and E. Igaki, “Visualizing Lithiation of Graphite Composite Anodes in All-Solid-State Batteries Using Operando Time-of-Flight Secondary Ion Mass Spectrometry,” J. Phys. Chem. Lett., vol. 12, no. 19, pp. 4623–4627, May 2021, doi: 10.1021/acs.jpclett.1c01089.[8] A. J. Merryweather, C. Schnedermann, Q. Jacquet, C. P. Grey, and A. Rao, “Operando optical tracking of single-particle ion dynamics in batteries,” Nature, vol. 594, no. 7864, Art. no. 7864, Jun. 2021, doi: 10.1038/s41586-021-03584-2. Figure 1

Operando Electrochemical Fluorescent Microscopy to Predict Li-Ion Battery Performance

A real-time, high-throughput visualization technique for heterogeneity in lithium-ion battery (LIB) electrodes is necessary to understand battery performance on a mechanistic level. Our group, along with others, has seen that battery performance is governed by short range (<20 um) electron transfer between the active material and carbon binder domain (CBD) in electrodes [1]–[3]. Available imaging techniques for visualizing the electronic connectivity of LIB electrodes are limited to nanoscale, single particle resolutions using sophisticated synchrotron X-ray or electron microscopy [4]–[6]. Optical microscopy offers the correct spatial resolution for visualizing the submicron connections of active particles to CBD, but is limited by the colorimetry of electrode materials- with graphite being the exception due to its visible color change during lithiation [7]. There is a rapidly growing body of research interested in studying the ionic diffusion pathways of Li-ion using operando optical microscopy, however none currently exist for studying the submicron electronic connectivity using an operando approach- especially under a industrially applicable lens [8]. To the best of our knowledge, this study presents the first spatially- and time- resolved technique for visualizing the electronic connectivity of commercial LIB electrodes using operando electrochemical fluorescent microscopy (EFM). This technique relies on the principle of electrofluorochromism, which we use to our advantage for a simple electrochemical system involving heterogeneous electron transfer. This allows us to use fluorescence as a real-time tracker for electronic heterogeneity, where electronic ‘dead-zones’ present as non-fluorescent regions in 2D images.Using this technique, we visualize commonly used commercial LIB electrodes (carbon content 1-4%, regimented processing), including NMC (LiNixMnyCo1-x-yO2), LFP (LiFePO4), and LCO (LiCoO2) against formulaically similar in-house made LIB electrodes (< 3.5% carbon content) as a proof of concept. We first validate the efficacy of this technique by testing commercial NMC, with a flaked off piece of active material, to show that areas of electronic discontinuities can in fact be represented by non-fluorescence (Fig.1.) We also find that when compared to commercial electrodes, those which are fabricated in house reveal isolated active particles, agglomerated carbon islands, and dead zones, undiscernible by brightfield imaging (Fig. 2.) Global feature extraction is performed on post-processed images to quantify electrode topology and evaluate electronic connectivity of active particles of battery electrodes, as well as heterogeneous mapping to determine the heterogeneity index of electrodes imaged. Testing our technique on low- and high- performing electrodes from an established library of coin-cell data allows for a straightforward way of correlating performance metrics to heterogeneity features. This quick (<1hr), reproducible visualization technique is general enough to be used to study the electronic connectivity of emerging new battery electrodes, as well as verify commercially available ones. Using this approach to verify LIB electrodes prior to assembly could save months to years of battery testing by being used as an alternative to lengthy full cell testing.[1] S. L. Morelly, N. J. Alvarez, and M. H. Tang, “Short-range contacts govern the performance of industry-relevant battery cathodes,” Journal of Power Sources, vol. 387, pp. 49–56, May 2018, doi: 10.1016/j.jpowsour.2018.03.039.[2] R. M. Saraka, S. L. Morelly, M. H. Tang, and N. J. Alvarez, “Correlating Processing Conditions to Short- and Long-Range Order in Coating and Drying Lithium-Ion Batteries,” ACS Appl. Energy Mater., vol. 3, no. 12, pp. 11681–11689, Dec. 2020, doi: 10.1021/acsaem.0c01305.[3] J. Entwistle, R. Ge, K. Pardikar, R. Smith, and D. Cumming, “Carbon binder domain networks and electrical conductivity in lithium-ion battery electrodes: A critical review,” Renewable and Sustainable Energy Reviews, vol. 166, p. 112624, Sep. 2022, doi: 10.1016/j.rser.2022.112624.[4] S. Li et al., “Mutual modulation between surface chemistry and bulk microstructure within secondary particles of nickel-rich layered oxides,” Nat Commun, vol. 11, no. 1, Art. no. 1, Sep. 2020, doi: 10.1038/s41467-020-18278-y.[5] P.-C. Tsai et al., “Single-particle measurements of electrochemical kinetics in NMC and NCA cathodes for Li-ion batteries,” Energy Environ. Sci., vol. 11, no. 4, pp. 860–871, Apr. 2018, doi: 10.1039/C8EE00001H.[6] A. Singer et al., “Nucleation of dislocations and their dynamics in layered oxide cathode materials during battery charging,” Nat Energy, vol. 3, no. 8, Art. no. 8, Aug. 2018, doi: 10.1038/s41560-018-0184-2.[7] Y. Yamagishi, H. Morita, Y. Nomura, and E. Igaki, “Visualizing Lithiation of Graphite Composite Anodes in All-Solid-State Batteries Using Operando Time-of-Flight Secondary Ion Mass Spectrometry,” J. Phys. Chem. Lett., vol. 12, no. 19, pp. 4623–4627, May 2021, doi: 10.1021/acs.jpclett.1c01089.[8] A. J. Merryweather, C. Schnedermann, Q. Jacquet, C. P. Grey, and A. Rao, “Operando optical tracking of single-particle ion dynamics in batteries,” Nature, vol. 594, no. 7864, Art. no. 7864, Jun. 2021, doi: 10.1038/s41586-021-03584-2. Figure 1

Multiphysics Simulation of Battery Electrode Drying

Scaling Li-ion battery production to meet the demands of increasingly electrified grids and transportation systems will require higher throughput at all levels of the battery cell production process. One of the more energy intensive battery manufacturing steps is the necessary drying of solvents which persist in the electrodes after the initial slurry coating of their current collectors. It is critical to both optimize this drying process to minimize the time and resources required, as well as to understand the effect that the drying has on the electrode microstructure. As it is both expensive and time-intensive to iteratively test different temperatures on multiple initial electrode microstructures, it is necessary to have reliable, high-fidelity simulations which can model the evaporation process. Furthermore, it is easier to control microstructural features such as porosity, and particle size in a simulated environment, Indeed, by simulating evaporation, the design-of-experiments space can be minimized, and process conditions can be established to accelerate the production of high quality, lower cost electrodes. To that end, we develop a multiphysics model of solvent evaporation using Sandia’s in-house finite element software. By coupling the solvent equations of motion to species conservation equations for the carbon binder material and energy flux driven by evaporative cooling, we demonstrate good agreement between simulation and simple evaporation experiments. This model tackles several difficult aspects of evaporation, namely the evolution of free surfaces and gas-liquid phase-changes. We additionally extend our model to account for mesoscale features (i.e. particle size, porosity, binder distribution) and determine how different temperature profiles and microstructures affect the heating requirements for the electrode. These extensions present a key advantage over conventional 1D models, as these features can have a significant effect on the evaporation process and the final distribution of conductive additive and binder. We leverage this advantage to examine how several design parameters such as porosity, particle size distribution, and heating rate affect the resulting electrode structure and binder distribution. These results demonstrate a pathway to optimizing the electrode drying process and promise to inform the development of improved multiphysics models in the future.SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

Pore Network Modelling of a Lithium Ion Battery Cathode as a Tool for Microstructure Optimization

Lithium ion batteries (LIBs) have become the battery of choice, owning almost 90% of the energy storage market [1]. They boast excellent power and energy density, but performance decreases at high discharge rates limiting their use in large scale applications [2]. With the availability of graphite and silicon materials as anode, the anode in a lithium-ion battery is already well optimized and research has focused primarily on the development of cathode materials with high rate-capacity. A LIB cathode is a porous material comprised of electrolyte, active material, and carbon binder phases. The electrolyte facilitates the migration and diffusion of lithium ions from the anode, through a porous separator, and to the active material where lithium ions intercalate, and electronic current is produced as the battery discharges. A carbon binder phase is also dispersed to enhance the electrical conductivity of the cathode and may even contain micropores that can increase current density [3]. The porous microstructure of a LIB cathode thereby plays an important role in controlling the movement of lithium ions and accessibility of active material effecting both discharge rate and capacity of LIBs. Therefore, tailoring the cathode microstructure provides a route for LIB cathode optimization. Pore scale models that resolve the electrolyte, active material, and carbon binder phases in a cathode can be used for this purpose. Pore scale models offer unique advantages compared to experimental studies in that they can test a wide variety of microstructures, even ones that are not yet realized, in a relatively short time frame. Typical battery models are continuum models that do not resolve the pore space and instead use effective properties determined from experiment. Pore scale models do not use effective properties saving experimental effort but are disadvantageous in that they are computationally very expensive requiring a fine mesh on a highly resolved volumetric image. Of the pore-scale modeling options, pore network modelling (PNM) is an especially efficient approach that discretizes the microstructure into pores and throats where pores are the computational nodes and throats are constrictions connecting pores [4]. In the literature, there is only one known pore network model of a LIB cathode, but it is an isothermal model that does not consider the effect of heat generation from electrochemical reactions [5]. While this model was effective at predicting discharge performance at low currents, predicting the voltage for galvanostatic discharge at high currents proved to be difficult, possibly because of assumed isothermal behaviour. Therefore, this work is focused on the development of a non-isothermal pore network model of a LIB cathode undergoing galvanostatic discharge. The complete set of partial differential equations and their discretization’s for modelling lithium transport, ionic or electronic charge transport, as well as heat transfer in all three phases of a LIB cathode is presented along with the numerical framework used for solving the coupled physics. This framework and discretized set of equations are demonstrated on a pore network extracted from an X-ray tomography image of a NMC532 cathode. Post-processing of the extracted network is done to apply novel interphase nodes between active material and electrolyte phases to provide sites for lithium intercalation to occur. The pore network model is written in Python using OpenPNM, an open-source pore network modelling package [6].[1] S. Zavahir et al., “A review on lithium recovery using electrochemical capturing systems,” Desalination, vol. 500, Mar. 2021, doi: 10.1016/j.desal.2020.114883.[2] R. Wagner, N. Preschitschek, S. Passerini, J. Leker, and M. Winter, “Current research trends and prospects among the various materials and designs used in lithium-based batteries,” J Appl Electrochem, vol. 43, no. 5, pp. 481–496, May 2013, doi: 10.1007/S10800-013-0533-6/FIGURES/10.[3] Z. A. Khan et al., “Probing the Structure-Performance Relationship of Lithium-Ion Battery Cathodes Using Pore-Networks Extracted from Three-Phase Tomograms,” J Electrochem Soc, 2020, doi: 10.1149/1945-7111/ab7bd8.[4] M. McKague, H. Fathiannasab, M. Agnaou, M. A. Sadeghi, and J. Gostick, “Extending pore network models to include electrical double layer effects in micropores for studying capacitive deionization,” Desalination, vol. 535, 2022, doi: 10.1016/j.desal.2022.115784.[5] Z. A. Khan, M. Agnaou, M. A. Sadeghi, A. Elkamel, and J. T. Gostick, “Pore Network Modelling of Galvanostatic Discharge Behaviour of Lithium-Ion Battery Cathodes,” J Electrochem Soc, vol. 168, no. 7, Jul. 2021, doi: 10.1149/1945-7111/ac120c.[6] J. Gostick et al., “OpenPNM: A Pore Network Modeling Package,” Comput Sci Eng, vol. 18, no. 4, pp. 60–74, Jul. 2016, doi: 10.1109/MCSE.2016.49. Figure 1

Experimental research of the effect of manufacturing holes and defects on the mechanical characteristics of laminated polymer composite

The paper presents a developed methodology for experimental research of the mechanical characteristics of a laminated polymer composite, taking into account manufacturing holes and defects. The results of experimental determination of mechanical characteristics are presented, the influence of the filler material, the type of fabric fiber weave, holes and manufacturing defects on the mechanical characteristics of laminated carbon fiber reinforced plastic are analyzed. The test specimens were made from carbon fiber 200T, 200P, ACM C300X and binder “Inject SL(B)”. Static tests of specimens for uniaxial tension, compression and three-point bending were performed.

Development and Experimental Verification of Inorganic Electromagnetic Pulse Shielding Paint for Building Interiors Using Carbon-Based Materials.

The term electromagnetic pulse (EMP) generally refers to high-power electromagnetic waves and can be classified into EMPs caused by nuclear weapons, non-nuclear EMPs, and EMPs caused by natural phenomena. EMPs can cause catastrophic damage to any electronic device consisting of electromagnetic components, including communications devices and transportation. In this study, the shielding effectiveness of paint was evaluated depending on the type and content of carbon material and binder. To analyze the compatibility and dispersibility improvement of the raw materials used in paint manufacturing, experiments were conducted in two stages, using 27 mixtures. The shielding effectiveness was evaluated for the optimal mixture developed through mixture experiments. The results of this study confirmed that the developed EMP shielding paint can improve the shielding effectiveness of concrete by 25-40 dB. Additionally, the adhesion strength and moisture resistance evaluation of the EMP shielding paint were evaluated. The average adhesive strength of the EMP shielding paint was 1.26 MPa. In moisture-resistance testing at a temperature of 50 ± 3 °C and a relative humidity of 95% or higher for more than 120 h, no cracks or peeling were observed on the painted surface.

Carbon Binder Domain Inhomogeneity in Silicon-Monoxide/Graphite Composite Anode by 2D Multiphysics Modeling.

The Carbon-binder domain (CBD) plays a pivotal role in the performance of lithium-ion battery electrodes. The heterogeneous distribution of CBD across the electrode has garnered significant attention. However, a thorough understanding of how this CBD inhomogeneity affects anode performance remains a crucial pursuit, especially when considering the inherent material variations present in the SiO/Graphite (SiO/Gr) composite anode. In this study, an electro-chemo-mechanical model is established that provides a detailed geometric description of the particles. This model allows to quantitatively uncover the effects of CBD inhomogeneity on the fundamental behaviors of the SiO/Gr composite anode. The findings indicate that reducing the proportion of CBD in the upper domain (near the anode surface) compared to the lower domain (near the current collector) positively influences electrochemical performance, particularly in terms of capacity and Li plating. However, such an arrangement introduces potential risks of mechanical failures, and it is recommended to incorporate a higher proportion of CBD alongside the SiO particles. Finally, an anode design with a lower CBD proportion in the upper domain exhibits superior rate performance. This study represents a pioneering modeling exploration of CBD inhomogeneity, offering a promising multiphysics model with significant potential for informing advanced battery design considerations.

Development of a low carbon binder system based on metakaolin: Focus on corrosion inhibitor-intercalated layered double hydroxides

In this work, MgO-CaO activated blends were produced by using metakaolin (MK). Roles of sodium nitrite (NaNO2) corrosion inhibitor on phase assemblance, micro-structure, and chloride binding of layered double hydroxides (LDH) in the systems were systematically studied. The results showed that the compressive strength in the middle and late stages were increased for 32.78% and 73.74% with the addition of CaO, and pore structure of the MgO-CaO-MK blends was optimized. After the addition of 5% NaNO2, NO2− anions were preferably intercalated into the layers of self-formed MgAl LDH and CaAl LDH. The chloride binding capacity of the samples was stronger than that of cement paste, which was attributed to the generation of more LDH by accelerating hydration of the system.

Development of an ettringite-based low carbon binder by promoting the nucleation and Ostwald ripening process

A low-carbon binder with ettringite as the main binding phase is prepared at ambient temperature using waste gypsum and metallurgical slag as raw materials. The technical limits of slow setting and low early strength are caused by the insufficient ettringite formation. This is tackled by fine tuning the thermodynamic route of ettringite formation process using polyaluminium compound via promoting the nucleation and Ostwald ripening process of ettringite formation. The high positive charge polymeric Al species and numerous Al(OH)4- generated by the hydrolysis of polyaluminium compounds increase the oversaturation degree and enhance the driving force of the Ostwald ripening process of ettringite. The volume ratio of ettringite/C-(A)-S-H in hydration products is further increased remarkably, resulting in the reduction of setting time and the enhancement of compressive strength. The carbon emission of the non-calcined ettringite-based binders developed in this study is 71–87 kg CO2-e/t. The research provides theoretical support for the development and application of a novel ettringite-based low carbon binders.

A multi-criterial optimization of low-carbon binders for a sustainable high-strength concrete using TOPSIS

The objective of this study is to focus on "low carbon binders," given the adverse environmental impacts resulting from the extensive emission of greenhouse gases. In the current context, the term "geopolymer concrete," often referred to as "low carbon binders," is gaining prominence as a means to develop an eco-friendly binding material. Furthermore, this study focuses on creating high-strength geopolymer binders using ambient curing conditions. Numerous factors are involved in determining the mix ratios for geopolymer concrete. Nonetheless, the reluctance to apply it in practical scenarios arises from an insufficient understanding of how to select the appropriate mix proportions based on these parameters. Therefore, utilizing Multi-Criteria Decision-Making presents the best choice for evaluating the geopolymer parameters. Among several MCDM methods, TOPSIS has been selected for this research. Geopolymer binders are produced using Ground Granulated Blast furnace Slag (GGBS), a by-product from the steel industry and metakaolin (MK), a product from the calcination of clay. A total of thirty-two combinations of geopolymer mortar mixes were created by varying the percentage of metakaolin, the ratio of alkaline activators (sodium silicate to sodium hydroxide, SS/SH), and the concentration of sodium hydroxide (NaOH). The assessment of these mixtures involves nine response factors, encompassing flow characteristics, initial and final setting time, compressive strength (7 and 28 days), initial drying shrinkage, energy consumption, CO2 emission, and financial expenses. A study of the microstructure is carried out to explore the impact of MK presence on geopolymers using GGBS as a base precursor. Hence, techniques for optimizing multiple responses were employed to attain the desired attributes while maintaining all measurable factors within an acceptable range. This approach to optimization holds significant importance, particularly when dealing with geopolymer concrete, as it can enhance its utilization compared to traditional cement-based concrete.

Adhesive and alloying properties of dual purpose polyfurfuryl alcohol binder for binder jet additive manufacturing of steel

In-situ alloying in steel can be achieved in the binder jet additive manufacturing process by incorporating alloying elements into the binder. However, using binders with nanoparticle suspensions often leads to challenges with particle dispersion uniformity and nozzle clogging. To circumvent these limitations, we investigated the feasibility of using a particle-free binder based on poly(furfuryl alcohol) (PFA) for binder jet 3D printing of steel. The PFA binder serves dual purposes – (i) imparting structural integrity to the as-printed green part and (ii) providing carbon upon pyrolysis to alloy the printed iron parts into steel. The PFA binder was first dispensed layer-by-layer into a low alloy steel powder bed to produce green parts with a storage modulus of 3360 MPa and a compressive strength of up to 9 MPa. Compared to the control, a commercial carbon binder ink, the present particle-free PFA formulation offered better green part rigidity (+18%) and strength (+18.5%) for the same amount of carbon alloying. The green parts were then subjected to debinding and sintering to consolidate the steel powder particles. During vacuum sintering, the PFA was pyrolyzed and left behind a carbon residue which diffused into the steel part to form a hard and strong ferrite-carbide aggregate phase that significantly enhanced the hardness, yield strength and ultimate tensile strength of the sintered steel parts. Furthermore, by varying the amount of this particle-free binder formulation at different locations, components with site-specific microstructures and mechanical responses, confirmed through hardness tests and digital image correlation, were also demonstrated.

Experimental study on eco-friendly one-part alkali-activated slag-fly ash-lime composites under CO2 environment: Reaction mechanism and carbon capture capacity

This work studied the reaction mechanism and carbon capture capacity of novel type eco-friendly one-part alkali-activated slag-fly ash-lime composites (SFL) based on the change in SFL under CO2 environment from the macroscale to the microscale. Experimental results showed that SFL had a higher carbonation rate and led to the formation of carbonates (calcite, vaterite, aragonite), gypsum, amorphous calcium carbonate, and alumino-silicate gel. The carbonation reaction of SFL can be generally divided into three periods. In period 3, Al from the decomposed aluminum-bearing hydrates was gradually incorporated into the amorphous silica phase in the form of tetrahedral Al(-SiO)4 sites, which finally resulted in the formation of an alumino-silicate gel. The mass ratio of carbon capture in the complete carbonation zone of SFL is approximately 13%. Due to a large amount of CO2 binding in hydrates in a wider carbonation zone, the actual total capacity of carbon capture in SFL under CO2 environment was slightly lower than that in Portland cement. Thus, SFL had a better and adjustable capacity for CO2 capture compared to other low carbon binder materials.