Materials Horizons Blog

3D printing has revolutionized the production of polymer-based materials, with the development of numerous printing techniques that continuously enhance speed, resolution, and accessibility. Among the most significant advancements is light-based 3D printing, which utilizes photopolymerization reactions to solidify inks, offering precise spatiotemporal control over the printing process. However, light-based 3D printing primarily relies on uncontrolled polymerization of (meth)acrylate and epoxide monomers/ cross-linkers, which yield non-functional, non-recyclable materials. To fully exploit the potential of 3D printing, there is growing interest in integrating advanced chemistries, such as dynamic chemistry, that enable the fabrication of functional materials capable of post-printing modifications in shape, properties, and functionality. Most polymer-based objects created through current 3D printing techniques cannot be chemically recycled due to the chemical inertness of the materials and the irreversible polymerization processes involved. Thus, it is imperative to incorporate new chemistries into 3D printing that enable the fabrication of advanced, functional, and chemically recyclable materials at the end of their lifecycle.

In a recent work by Du Prez and Nguyen, a closed-loop 3D printing process utilizing dynamic chemistry was reported. The authors synthesized an acrylate photocurable polymeric material based on dynamic β-amino ester cross-linkers, which can be used as an ink for 3D printing. Importantly, this material can undergo decross-linking via a transesterification reaction, resulting in the depolymerization of the formed polymer network. This process is not only reversible, enabling the making and unmaking of polymers, but it also operates under highly appealing and relatively mild conditions.

The team first synthesized an acrylate-terminated β-amino ester-containing cross-linker, which serves as a building block for the formation of a dynamic polymer network. This cross-linker was prepared via a one-step aza-Michael addition reaction. The process is straightforward and utilizes commercially available reagents, making the material easily adaptable for other researchers. These low-molecular-weight diacrylate polymers undergo photo-induced free radical polymerization, resulting in the formation of a dynamic polymer network.

This dynamic nature of the polymeric network enables thermomechanical reprocessing of the material. To demonstrate this aspect, the authors used compression molding (at 150 °C under 2 tons of pressure for 30 minutes) for reprocessability. The recycling procedure was repeated three times, with the material showing a slight increase in shear modulus and activation energy, while maintaining stable thermal properties and chemical integrity. The increase in temperature results in a reduction of cross-link density, demonstrating the role of dissociative exchange via (retro) aza-Michael addition. In contrast, polymeric networks without dynamic bonds did not exhibit any reprocessability, highlighting the promise of dynamic chemistry in enabling reprocessable materials.

In the next step, to demonstrate more advanced chemical recycling of this dynamic network, the team employed another reaction (transesterification) using a commercially available methacrylate with a hydroxyl moiety (hydroxyethyl methacrylate) as a decross-linker. The hydroxyl group of this functional methacrylate reacts with the β-amino ester, resulting in the decross-linking of the network and its depolymerization. This reaction is temperature-dependent and requires an optimized amount of decross-linker to achieve a high depolymerization yield. Notably, the depolymerization reaction proceeds without the need for any catalyst or solvent, making the procedure even more appealing. Upon depolymerization of the polymer network, the resulting mixture consists of methacrylate-terminated compounds, as confirmed by electrospray ionization mass spectrometry. These compounds can be further employed for another cycle of photo-curing, enabling the development of curable-depolymerizable dynamic materials.

In the final part, the team demonstrated the translation of this concept into closed-loop 3D printing using the dynamic photocurable resin. Multiple printing cycles were performed with recycled photocurable resin to assess the repeatability of this procedure. The resulting samples exhibited consistent shapes and appearances for at least three cycles, thus demonstrating repeatable printability after chemical recycling.

Overall, this study elegantly combines fundamental aspects of dynamic polymer chemistry and its application in 3D printing, further enhancing interest in dynamic chemistry for both functional and recyclable materials.

To find out more, please read:

Direct restoration of photocurable cross-linkers for repeated light-based 3D printing of covalent adaptable networks
Loc Tan Nguyen and Filip E. Du Prez
Mater. Horiz., 2024, DOI:10.1039/D4MH00823E

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About the blogger

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Dr. Kostas Parkatzidis is a Swiss National Science Foundation Postdoc Fellow in the group of Professor Zhenan Bao at Stanford University (United States), working on the molecular design of polymer-based skin-inspired materials for various applications. Kostas obtained his PhD from ETH Zurich (Switzerland) under the supervision of Professor Athina Anastasaki where he focused on the development of advanced polymer synthesis and chemical recycling methodologies. He also holds MSc in Organic Chemistry and BSc in Materials Science and Engineering obtained from the University of Crete (Greece). Since 2023, Kostas has served as a Materials Horizons Community Board member.

Perovskite oxynitrides are intriguing materials with significant relevance in photoelectrochemistry and catalysis. Their crystallinity is often simplified using high-symmetry unit cells as a convenient approximation. However, this approach fails to capture the complex local atomic displacements of anions and neighboring cations caused by the differing ionic radii of oxygen and nitrogen anions. A recent study by the Seitz Group provides a more nuanced understanding of perovskite oxynitrides’ true crystallinity, using a newly synthesized calcium tungsten oxynitride, CaW(O,N)₃, as a model system. The authors leverage experimental and computational techniques to explore its crystal structure, focusing on distortion, anion ordering, and symmetry. This study highlights four key findings:

CaW(O,N)₃ exhibits structural distortion. The study marks the first successful synthesis of CaW(O,N)₃. Using a combination of density functional theory (DFT), X-ray diffraction (XRD), and neutron diffraction (ND), the authors reveal that this material adopts an orthorhombic Pnma average structure. This structure exhibits significant octahedral distortion and preferential anion site occupancy, highlighting its deviation from a purely symmetric model.

Symmetry models for perovskite oxynitrides need to account for disorder. The authors demonstrate that traditional high-symmetry models fail to capture the full complexity of CaW(O,N)₃. Instead, a low-symmetry model with a P1 space group—which incorporates a larger unit cell and random anion positioning—better represents the disorder inherent in the crystal. This disorder forms a “polymorphous network,” where the observed high symmetry is only an average, masking the true lower local symmetry of CaW(O,N)₃.

The structural disorder can be extended to other perovskite oxynitrides. The structural disorder observed in CaW(O,N)₃ was also identified in its analog, SrW(O,N)₃. Like CaW(O,N)₃, the authors obtained a better representation of the structural disorder in SrW(O,N)₃ by applying similar low-symmetry models, suggesting that such disorder is a common characteristic across perovskite oxynitrides.

Structural disorder in perovskite oxynitrides causes changes in electronic properties. Comparative X-ray Absorption Spectroscopy (XAS) revealed differences in electronic structures between Ca- and Sr-based perovskite oxynitrides. SrW(O,N)₃ exhibits stronger covalency between its anions and W 5d orbitals. These differences are attributed to the distinct electronic configurations and ionic radii of Ca²⁺ and Sr²⁺, which alter the interaction of W with neighboring anions.

 

 

In summary, this study provides a comprehensive evaluation of the crystallinity and electronic properties of perovskite oxynitrides, emphasizing the importance of structural disorder. This work is a must-read for researchers studying heteroanionic materials, offering guidance on characterizing their structural and electronic properties through essential experimental and computational methods. Furthermore, it underscores the need for more sophisticated models to accurately represent these materials’ symmetry and local structure, accounting for the inherent complexities introduced by mixed anion occupancy. These findings are crucial for optimizing perovskite oxynitrides’ performance in catalytic and photoelectrochemical applications, where electronic and structural properties are pivotal in their performance.

To find out more, please read:

Synthesis and symmetry of perovskite oxynitride CaW(O,N)₃
Matthew E. Sweers, Tzu-chen Liu, Jiahong Shen, Bingzhang Lu, John W. Freeland, Christopher Wolverton, Gabriela B. Gonzalez Aviles, and  Linsey C. Seitz
Mater. Horiz., 2024,11, 4104-4114 DOI: 10.1039/D4MH00317A

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About the blogger

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Raul A. Marquez is a Ph.D. in Chemistry candidate working with Prof. C. Buddie Mullins at The University of Texas at Austin and a Materials Horizons Community Board member. His research focuses on understanding the transformations of electrocatalytic materials and developing advanced characterization methods for energy storage and conversion technologies. Follow Raul’s latest research on LinkedIn.

Current ionic conductors, such as hydrogels and ionogels, offer diverse capabilities but also exhibit limitations. These systems rely on a substantial amount of liquid to provide a mobile environment for free ions, while a covalently crosslinked network enhances mechanical strength. However, the presence of liquid compromises thermal and electrochemical stability and reduces mechanical integrity. Furthermore, the covalently crosslinked network often results in irreversible polymer structures, creating a fundamental conflict between ionic conductivity, self-healing capabilities, and mechanical performance—challenges that are particularly pronounced in flexible and wearable ionotronic devices. To address these issues, many researchers are focusing on developing versatile ionic conductive elastomers with innovative polymer molecular structures. Yet, the design of liquid-free ion-conducting elastomers typically struggles to achieve high ionic conductivity due to restricted segmental motion of polymer chains in covalently crosslinked networks, leading to significantly slower ion transport efficiency and a reduced volume of free ions.

To enhance molecular segmental motion and ion transport, Ou and colleagues recently proposed a strategy that combines dual dynamic covalent bonds with non-covalent interactions. By integrating multilevel hydrogen bonds, disulfide bonds, and dynamic donor-acceptor (D–A) bonds into a polyurethane system, they developed liquid-free ionic conductive polyurethane elastomers (ICPEs), designated as SS₅₀DA₅₀–LiTFSI_z%. Polytetramethylene ether glycol was selected as the soft phase, whereas the ether chain segments engage in ionic transport through loosely coordinated lithium-oxygen (O–Li⁺) bonding interactions. This configuration facilitates the development of all-solid ICPEs characterized by high ionic conductivity. The well-designed structure of SS₅₀DA₅₀ enables self-healing at 130°C for 2 hours, achieving a high tensile strength of 58.90 MPa and toughness of 260.33 MJ m^-3, with a healing efficiency of 92% and complete recyclability. This performance is attributed to the dynamic covalent crosslinked bonds that maintain the relative positions of the polymer chain segments under tension, thereby maintaining the three-dimensional integrity of the network and substantially improving both the tensile strength and toughness of the elastomers. Additionally, the ICPEs (SS₅₀DA₅₀–LiTFSI_80%) demonstrated high mechanical strength (1.18 MPa), superior ionic conductivity (0.14 mS cm^-1), and excellent healing capacity (healing efficiency >95%), highlighting their potential as wearable sensors for physical rehabilitation training.

Because of their excellent sensitivity and durability properties, the SS₅₀DA₅₀–LiTFSI_80% elastomers are used in multifunctional sensors and triboelectric nanogenerators, capable of real-time and rapid detection of various human activities, and can recognize writing signals and encrypted information transmission. Furthermore, SS₅₀DA₅₀–LiTFSI_80% achieved an excellent open-circuit voltage of 464 V, a short-circuit current of 16 mA, a transferred charge of 50 nC, and a power density of 720 mW m^-2. Its outstanding output performance offers significant practical value for wearable electronics and self-powered products.

In summary, the innovative design of ICEs such as SS₅₀DA₅₀–LiTFSI_80% features a polyurethane matrix enriched with multiple dynamic bonds, including hydrogen and disulfide bonds. This design offers a more robust and sustainable alternative with enhanced functionality compared to traditional hydrogels. The improved mechanical properties, healing abilities, and recyclability of these materials make them pivotal for the future of flexible and wearable technology. The potential applications of these elastomers extend from sustainable wearable electronics to energy-harvesting devices and solid-state polymer electrolytes.

To find out more, please read:

Liquid-free ionic conductive elastomers with high mechanical properties and ionic conductivity for multifunctional sensors and triboelectric nanogenerators
Fangyan Ou, Ting Xie, Xinze Li, Zhichao Zhang, Chuang Ning, Liang Tuo, Wenyu Pan, Changsheng Wang, Xueying Duan, Qihua Liang, Wei Gao, Zequan Li,* and Shuangliang Zhao
Mater. Horiz., 2024, DOI: 10.1039/d3mh02217j

 

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About the blogger

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Fang Cheng Liang is currently a Lecturer in the Department of Materials Science and Engineering at the National University of Singapore (NUS) and serves as a Community Board member for Materials Horizons. Before joining NUS, he was a Research Assistant Professor at the Research and Development Center for Smart Textile Technology at the National Taipei University of Technology, Taiwan. He earned dual Ph.D. degrees in Organic Chemistry and Polymer Science and Engineering from the University Grenoble Alpes and National Taipei University of Technology in 2019. His research focuses on sustainable self-healing soft materials, liquid metal hydrogels, reconfigurable liquid crystal elastomers, and hybrid organic-inorganic perovskite applications in light-emitting diodes, triboelectric nanogenerators, soft robotics, and wearable electronics.

Patients with diabetes frequently develop chronic ulcers on their lower extremities that are extremely challenging to treat. To accelerate healing, numerous wound dressings have been developed to protect damaged tissue and possibly deliver therapeutics. However, few dressings can provide real-time monitoring of wound healing and patient health. Since diabetic ulcers are prone to persistent hyperglycemia, ischemia, prolonged inflammation, and bacterial infections, frequently assessing biomarkers is essential to optimize treatment and maximize healing outcomes.

In a recent work by Hou et. al., a multifunctional wound dressing is developed to not only shield diabetic foot wounds from insult and bacterial infections, but record wound site temperature, pH, and glucose levels. Additionally, the flexible electronic also monitors physiological signals such as patient heart rhythm and brain activity. To create the diagnostic dressing, a poly(ethylene glycol)-based polymer possessing cationic and anionic moieties, as well as the self-complementary hydrogen-bonding group, ureidopyrimidinone (UPy) is developed. The polymer abbreviated PADU after the first letter of each constituting monomer, forms flexible substrates due to intermolecular UPy interactions as well as ionic bonding between cationic and ionic segments.

 

 

When applied to metals, rubber, plastic, glass, and biological tissues, PADU substrates display remarkable adhesion, notably exceeding an adhesive strength of 13 kPa for both diabetic and healthy mouse skin. Following damage to the patch, dynamic hydrogen bonding also endows PADU materials with self-healing capabilities, restoring 96% of their original mechanical strength after 24 hours. In practical use this gives PADU substrates a huge advantage because may be able to sustain electronic function despite physical damage from bodily movement.

In addition to its superb mechanical properties, PADU was also found to exhibit antibacterial activity. Killing of bacteria is achieved through disruption of the cell membrane by cationic groups within the polymer, making it active against even drug-resistant pathogens. Co-cultures with mammalian cells and blood cells, however, showed no cytotoxic or hemolytic effects, and biocompatibility was further confirmed by subcutaneous implantation into mice.

When glucose, pH, and temperature sensors were printed on PADU substrates, real-time monitoring of environmental conditions were reported with high accuracy. Gold foil electrodes could also be easily integrated into the patch to produce dressings capable of collecting electrocardiograms, electromyographic signals, and electroencephalograms. Due to their strong adhesion to skin, PADU-based sensors could even collect electrophysiological readings while patients were in motion, exceeding the accuracy of commercial sensors.

The dressing developed in the work by Hou, et. al. surpasses the capabilities of most diabetic wound dressings due its multifunctional performance as an adhesive and versatile electronic. Although initially designed for diabetic ulcers, the technology will likely find broad use as a diagnostic dressing for any type of slow-healing wound. In future studies, electronic patches may even be studied as implantable materials to monitor surgical site healing or internal injuries. Overall, the work demonstrates the vast utility of flexible bioelectronics and highlights the importance of developing new devices that not only treat but monitor chronic wounds.

To find out more, please read:

Skin-adhesive and self-healing diagnostic wound dressings for diabetic wound healing recording and electrophysiological signal monitoring
Zishuo Hou, Tengjiao Wang, Lei Wang, Junjie Wang, Yong Zhang, Qian Zhou,   Zhengheng Zhang, Peng Li and Wei Huang
Mater. Horiz., 2024, Advance Article, DOI: 10.1039/D3MH02064A

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About the blogger

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Kelsey DeFrates is a Materials Horizons Community Board member. She received her Bachelor of Science in Bioengineering at Rowan University (Glassboro, New Jersey) in 2018 and completed her Ph.D. in Bioengineering through the University of California, Berkeley – UCSF joint graduate program in 2023. For her thesis research, Kelsey worked with Professor Phillip Messersmith at UC Berkeley on the development of supramolecular materials for drug delivery and tissue regeneration. In 2023, Kelsey joined Professor Christopher Hernandez at UCSF as a Chancellor’s Postdoctoral Fellow, where she is working to understand how bacteria sense and respond to physical stimuli. In future work, Kelsey hopes to use this information to develop engineered living materials for healthcare and sustainable building.

Neuromorphic computing, inspired by the structure of the human brain, aims to overcome the limitations of traditional computing architectures by more closely integrating processing and memory functions. It is believed that this approach is a step towards dramatically improving the efficiency of artificial neural networks by in-memory computing. Specifically, compared to conventional graphics processing units, the memristor crossbars connected by synapses would markedly enhance the training and inference of the artificial neural networks in terms of speed and power for natural language processing, image classification, and so forth.

Due to their tantalizing properties, including unique control of ionic processes, mechanical flexibility, and low cost processability, organic materials, such as small molecules, polymers, graphene oxides, and halide perovskites, have sparked considerable research interests for crossbar memristive materials for artificial neural networks. Nevertheless, some weaknesses, such as dissatisfactory environmental stability, irreproducible switching behavior, and lack of understanding of the switching mechanisms, inevitably limit their applications for such application. Thus, it is of vital importance to rationally design new organic materials for crossbar memristors and synapses, to thoroughly understand their mechanisms, and to characterize their performance.

Recently, Vishwanath et al. designed, fabricated, and evaluated one-dimensional halide perovskites for crossbar memristive materials for application in artificial neural networks. They synthesized two kinds of one-dimensional halide perovskites, one with the organic cation of propylpyridinium and the other with the organic cation of benzylpyridinium. The substituted pyridines were used as templating agents to construct the one-dimensional structures. Compared to the three-dimensional perovskites, these exhibit better resistive switching performance due to their larger band gaps.

In order to maximize the improvement of their reliability, endurance, and retention, a device configuration of Ag/PMMA/HP/PEDOT:PSS/ITO was adopted, in which the halide perovskites switching matrix is sandwiched between the poly(methyl methacrylate) (PMMA) isolated layers and the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). By employing the widely-used solution-processable technique, the team elaborately fabricated the largest dot point and crossbar halide perovskites memristive arrays so far (50000 devices across an area of 100 cm² and 16×16 crossbar).

Furthermore, they comprehensively analyzed the analog programming window for the halide perovskites. Concurrently, a spiking neural network with halide perovskite synapses was trained to classify the handwritten digits from the Modified National Institute of Standards and Technology database, which corroborates the applicability of the spike-timing-dependent plasticity learning of one-dimensional halide perovskite memristive synapses.

In summary, this novel study pioneers a new path for high-performance neuromorphic computing with innovative halide perovskites as the active material. These insightful results not only offer a solid foundation for the future explorations of halide perovskites in state-of-the-art neuromorphic computing, but also highlight the significance of materials innovation in unlocking the potential of next-generation computing technologies.

To find out more, please read:

High-performance one-dimensional halide perovskite crossbar memristors and synapses for neuromorphic computing
Sujaya Kumar Vishwanath, Benny Febriansyah, Si En Ng, Tisita Das, Jyotibdha Acharya, Rohit Abraham John, Divyam Sharma, Putu Andhita Dananjaya, Metikoti Jagadeeswararao, Naveen Tiwari, Mohit Ramesh Chandra Kulkarni, Wen Siang Lew, Sudip Chakraborty, Arindam Basuf and Nripan Mathews
Mater. Horiz., 2024, Advance Article, DOI: 10.1039/d3mh02055j

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About the blogger

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Wen Shi is currently an Associate Professor at School of Chemistry, Sun Yat-sen University and a Materials Horizons Community Board member. He received his Ph.D. in physical chemistry from Tsinghua University in 2017. From 2017 to 2021, he worked as a scientist at Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR) in Singapore. Dr. Shi’s current research interests are in theoretical computations and simulations of functional materials.

 

In the ever-evolving landscape of materials engineering, researchers are pushing the boundaries of sustainability and functionality. One groundbreaking avenue of exploration is the integration of mycelium, the root-like structure of fungi, into biocomposites. In this blog post, we delve into a recent study that harnesses the unique properties of mycelium through 3D printing and indirect inoculation, resulting in a material with enhanced mechanical strength and diverse applications.

Shen et al. formulated a biocomposite designed to offer mechanical robustness and compatibility with mycelium. To achieve this, the researchers ingeniously selected chitosan and cellulose and introduced leftover coffee grounds as a sustainable source of nutrients. This careful combination created a material that not only exhibited shear thinning behavior, ideal for 3D printing but also laid the foundation for mycelium colonization (Figure 1).

One distinguishing feature of this study is the use of indirect inoculation for mycelium colonization. Traditionally, direct inoculation involves mixing the inoculum with the composite material before printing. However, the researchers chose a different route, incubating printed samples on a bed of live mycelium. This indirect approach, although taking longer for full colonization, turned out to be more effective.

The study of the mechanical properties of biocomposites revealed a strong influence on the orientation of the 3D printing tool path and the alignment of the cellulose fibers. The authors printed parts of different shapes, and the mechanical properties were dependent on the printing design. However, the fully colonized material showed a notable increase in mechanical strength, surpassing previously reported mycelium composites.

 

The influence of mycelium extended beyond mechanical properties to wettability and absorption characteristics. The fully colonized composite developed a smooth hydrophobic “skin,” demonstrating improved water contact angles. Under submerged conditions, the colonized compound demonstrated lower water absorption and volume swelling, attributed to the presence of hydrophobic mycelial hyphae.

The team explored the capabilities of mycelium to develop biosealed mycelium containers as self-sealing living boxes and the creation of flexible textile-like materials through precise 3D printing and mycelium colonization. By printing biocomposite panels with consistent gaps and allowing mycelium to cover them, flexible hinges were formed, enabling the creation of a material capable of bending and stretching in multiple directions.

In conclusion, the fusion of 3D printing, indirect inoculation, and mycelium colonization represents a leap forward in the field of sustainable biocomposites. The mechanical properties, wetting characteristics, and adaptability of the biocomposite open avenues for green alternatives in packaging, textiles, and more.

To find out more, please read:

Robust myco-composites: a biocomposite platform for versatile hybrid-living materials
Sabrina C. Shen, Nicolas A. Lee, William J. Lockett, Aliai D. Acuil, Hannah B. Gazdus, Branden N. Spitzerab  and Markus J. Buehler
Mater. Horiz., 2024, Advance Article, DOI: 10.1039/D3MH01277H

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About the blogger

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Dr. Danila Merino is the PI of the SusBioComp group at POLYMAT and a Materials Horizons Community Board member. Her research focuses on the development of new sustainable biocomposite materials derived from biomass specifically designed to protect and enhance agricultural and food systems with minimal environmental impact.

To address the need for large-scale electrochemical energy storage (EES), much research attention has moved beyond Li-ion batteries due to safety and security-of-supply issues. Sodium, an alkali-metal which is much more abundant and well-distributed globally, is of keen interest as its mining process is cleaner and freer from ethical concern. Moreover, to avoid the high flammability of organic electrolytes, some researchers are looking towards aqueous sodium-ion batteries as a potential contender for future EES systems. This has the added benefit of increasing the ionic conductivity by as much as two orders of magnitude versus organic equivalents, potentially enabling higher rate capability. However, moving from traditional carbonate-based electrolytes to water means a narrowing of the electrochemical stability window and the need for electrodes to facilitate the intercalation and de-intercalation of hydrated cations. Given the smaller accessible voltage and the larger charge carrier, aqueous sodium-ion batteries are still plagued by low specific energy and limited lifespans.

Therefore, the development of new electrode materials to maximise specific capacity is an important research direction. For the anode material, much attention has been paid to the development of polyanionic materials, such as sodium superionic conductors (NASICON), but also carbon-based materials such as polypyrrole and polyimide systems. In recent work by Maria K. Ramos et al., however, the synthesis of a graphene-based composite thin-film was presented, incorporating two compounds that had been shown to have high capacities but suffered from low conductivity and significant volume changes.

Specifically, the researchers highlighted the difficulty of producing ternary thin-films by traditional fabrication routes (e.g., spin-coating, vapour deposition etc.), spurring the development of a liquid-liquid interfacial route (LLIR) for the self-assembly of materials at the interface of immiscible liquids to give a continuous network that can be deposited on any solid substrate. MoS₂, known to facilitate the intercalation and de-intercalation of hydrated sodium ions, and non-toxic copper oxide nanoparticles with high theoretical specific capacity, were combined with graphene in this way to produce ternary films that were electrochemically characterised.

Interestingly, the researchers detailed three different thin-film preparation approaches using their LLIR method (Figure 1). The in-situ approach, whereby graphene oxide and Cu²⁺ were simultaneously reduced in a dispersion of MoS₂, yielded a thin-film anode material that demonstrated a very high specific capacity of 1377 mA h g^-1 (c.f. specific capacity of typical lithium-ion batteries is < 200 mA h g^-1).

In summary, the successful implementation of this in-situ liquid-liquid interfacial method for thin-film preparation provides encouragement for its use to produce other composite electrode materials, and a greater understanding of its scalability. The demonstration of such a high-capacity aqueous sodium-ion battery electrode should encourage greater exploration of this more sustainable, beyond-lithium EES technology.

To find out more, please read:

Nanoarchitected graphene/copper oxide nanoparticles/MoS₂ ternary thin films as highly efficient electrodes for aqueous sodium-ion batteriesMaria K. Ramos, Gustavo Martins, Luiz H. Marcolino-Junior, Márcio F. Bergamini, Marcela M. Oliveira and Aldo J. G. Zarbin
Mater. Horiz., 2023, 10, 5521-5537, DOI: 10.1039/d3mh00982c

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About the blogger

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Dr Josh J Bailey is an Illuminate Fellow at Queen’s University Belfast, focused on the implementation and optimisation of ionic liquids used in polymer electrolyte fuel cells and is a Materials Horizons Community Board member. He received his doctoral degree from University College London, UK, as part of the Centre for Doctoral Training in Advanced Characterisation of Materials, investigating electrode degradation in solid oxide fuel cells. His research interests span fuel cells, lithium-ion batteries, solid-state batteries, and flow batteries, both in terms of the design of novel electrodes, electrolytes, and membrane materials, as well as the study of materials degradation, with a view to improving performance and durability.