Nanoscience News (<front>)

This review probes recent advancements in PEMWEs for green hydrogen production from the perspective of acidic OER, identifies challenges related to corrosive environments and oxidative conditions, and proposes strategies to enhance the long-term stability of PEMWEs by addressing both catalyst and membrane electrode assembly deactivation.

Abstract

Proton exchange membrane water electrolysis (PEMWE) represents a promising technology for renewable hydrogen production. However, the large-scale commercialization of PEMWE faces challenges due to the need for acid oxygen evolution reaction (OER) catalysts with long-term stability and corrosion-resistant membrane electrode assemblies (MEA). This review thoroughly examines the deactivation mechanisms of acidic OER and crucial factors affecting assembly instability in complex reaction environments, including catalyst degradation, dynamic behavior at the MEA triple-phase boundary, and equipment failures. Targeted solutions are proposed, including catalyst improvements, optimized MEA designs, and operational strategies. Finally, the review highlights perspectives on strict activity/stability evaluation standards, in situ/operando characteristics, and practical electrolyzer optimization. These insights emphasize the interrelationship between catalysts, MEAs, activity, and stability, offering new guidance for accelerating the commercialization of PEMWE catalysts and systems.

Geospatial Analysis of Bacterial Meningitis Outbreaks in Africa

Molly is a first year PhD student working on the epidemiology of meningitis in relation to climate change. Before starting her PhD, Molly graduated with an MSc in Tropical Disease Biology from the Liverpool School of Tropical Medicine and worked as an epidemiologist at the UK Health Security Agency. Whilst at UKHSA Molly conducted analysis on a wide variety of communicable disease outbreaks and undertook a secondment with the World Health Organisation, supporting the European MPox outbreak.

Chaired by Liza Hadley and Andrew Grant

• Speaker: Molly Cliff, Department of Veterinary Medicine
• Friday 14 March 2025, 08:45-10:00
• Venue: LT2.
• Series: Friday Morning Seminars, Dept of Veterinary Medicine; organiser: Fiona Roby.

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A sustainable Zn interfacial architecture is established, where a robust polyimide nanofilm is covalently anchored to the Zn substrate through electronegative F atoms. The strong covalent interactions provide excellent interfacial adhesion during repeated Zn/Zn2+ cycling. The remarkable resilience, modulus, and low creep of FPI film effectively resist the impact stress from electroplated Zn while maintaining structural integrity.

Abstract

Artificial interfacial protective coatings (IPCs) on Zn anodes provide a viable solution for suppressing dendritic growth by spatially confining and homogenizing the Zn2+ flux. However, repeated Zn deformation during electroplating/stripping cycles can lead to the rupture or exfoliation of IPCs, as well as the formation of detrimental interfacial gaps. Herein, a highly durable IPC is developed on a Zn substrate using a mechanically robust fluorinated polyimide nanofilm (FPI). This unique FPI interphase forms strong covalent bonds with Zn through electronegative fluorine atoms, facilitating Zn plating/stripping while maintaining interfacial adhesion. The superior resilience, modulus, and low creep of the FPI film resist the impact stresses from electroplated Zn, ensuring structural integrity. With this FPI coating, the FPI-Cu||Zn half cells demonstrate high reversibility in Zn2+ electroplating/stripping over 4000 h, maintaining Coulombic efficiency above 99.33%. When coupled with a MnO2 cathode, the MnO2||FPI-Zn full cells exhibit a long lifespan, surpassing 5000 cycles, with a high specific capacity retention of 75.21%. This study highlights the importance of achieving a balance between the customized compatibility and mechanical properties of IPCs to modulate zinc interfacial chemistries.

An infrared-sensitive image sensor based on self-welded tellurium (Te) nanomesh is proposed, demonstrating advancements in flexible integration and scalable fabrication. By leveraging the unique photothermolelectric (PTE) operation, thermal-coupled bi-directional photoresponse is explored to illustrate the proof-of-principle in-sensor convolutional network for edge computing.

Abstract

The inherent limitations of traditional von Neumann architectures hinder the rapid development of internet of things technologies. Beyond conventional, complementary metal-oxide-semiconductor technologies, imaging sensors integrated with near- or in-sensor computing architectures emerge as a promising solution. In this study, the multi-scale van der Waals (vdWs) interactions in 1D tellurium (Te) atomic chains are explored, leading to the deposition of a photothermoelectric (PTE) Te nanomesh on a polymeric polyimide substrate. The self-welding process enables the lateral vapor growth of a well-connected Te nanomesh with robust electrical and mechanical properties, including a PTE responsivity of ≈120 V W−1 in the infrared light regime. Leveraging the PTE operation, the thermal-coupled bi-directional photoresponse is investigated to demonstrate a proof-of-principle in-sensor convolutional network for edge computing. This work presents a scalable approach for assembling functional vdWs Te nanomesh and highlights its potential applications in PTE image sensing and convolutional processing.

“Primitive steroidogenesis in mast cells: A novel regulatory mechanism for mast cell function”

This Cambridge Immunology and Medicine Seminar will take place on Thursday 6 March 2025, starting at 4:00pm, in the Ground Floor Lecture Theatre, Jeffrey Cheah Biomedical Centre (JCBC)

Speaker: Dr Bidesh Mahata, Department of Pathology, University of Cambridge

Title: “Primitive steroidogenesis in mast cells: A novel regulatory mechanism for mast cell function”

Host: Virginia Pedicord, CITIID , Cambridge

There will be an opportunity for networking with colleagues from across the network and refreshments following the talk.

We want to encourage in-person attendance. However, if you are unable to join us, please email enquiries@immunology for a Zoom link.

• Speaker: Dr Bidesh Mahata, Department of Pathology, University of Cambridge
• Thursday 06 March 2025, 16:00-17:00
• Venue: Lecture Theatre, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus.
• Series: Cambridge Immunology Network Seminar Series; organiser: Ruth Paton.

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Towards a Faster Finality Protocol for Ethereum

Ethereum’s Gasper consensus protocol typically requires 64 to 95 slots-the units of time during which a new chain extending the previous one by one block is proposed and voted-to finalize, even under ideal conditions with synchrony and honest validators. This exposes a significant portion of the blockchain to potential reorganizations during changes in network conditions, such as periods of asynchrony.

In this talk, I will introduce 3SF, a novel consensus protocol that addresses these limitations. With 3SF, finality is achieved within just three slots after a proposal, drastically reducing the exposure to reorganizations. This presentation will explore the motivation, design, and implications of 3SF, offering a new perspective on the future of Ethereum’s consensus protocol.

Paper: https://arxiv.org/abs/2411.00558

Zoom link: https://cam-ac-uk.zoom.us/j/82398112798?pwd=vg2ZZm8mdSBW8A8mkkaMOOqSaFEgzw.1

Meeting ID: 823 9811 2798 Passcode: 784044

• Speaker: Luca Zanolini, Ethereum Foundation
• Tuesday 04 March 2025, 14:00-15:00
• Venue: Webinar & GN06, Computer Laboratory, William Gates Building..
• Series: Computer Laboratory Security Seminar; organiser: Tina Marjanov.

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A D–A–D type TADF molecule, TPA-DHAQ, is designed and synthesized by introducing an ESIPT-active molecule DHAQ as the acceptor unit, based on which the NIR TADF laser with a low threshold and high stability is successfully realized. In addition, a single-mode NIR TADF laser can be realized by adjusting the size of the resonator. This work provides a novel molecular design strategy to overcome the problem of poor stability of conventional NIR organic lasers.

Abstract

Near-infrared (NIR) organic lasers have undergone rapid development in recent years, but still facing challenges in lowering the threshold and improving the stability. Herein, to overcome these challenges, a “two in one” strategy involving the integration of thermally activated delayed fluorescence (TADF) and excited-state intramolecular proton transfer (ESIPT) activity in a single molecule is proposed. Specifically, a donor–acceptor–donor type TADF material 2,6-bis[4-(diphenylamino)phenyl]-1,5-dihydroxyanthraquinone (TPA-DHAQ) with an ESIPT-active moiety as the acceptor, is designed and synthesized, based on which, a NIR organic laser at 820 nm with an exceptionally low threshold of 6.3 µJ cm−2 can be realized. Benefiting from the synergistic effect of the TADF property and the ESIPT process, the resulting organic laser showed excellent stability by maintaining the laser intensity at ≈80% of the initial value after 580 min of continuous excitation. Finally, by modulating the size of the resonator, a single-mode NIR laser is successfully realized. This work provides a novel molecular design strategy for the development of new TADF gain materials to overcome the problem of high threshold and poor stability of conventional NIR organic lasers, and shed light on the future development of NIR organic lasers.

Meter-scale MXene/GO@monstera nanocellulose core-shell nanofiber textiles are produced, integrating ultra-broadband EMI shielding covering GHz and THz bands, super-strong stealth properties within NIR and MIR ranges, and excellent multifunctionality, including heat resistance, flame retardant, joule heating, and stress sensing capabilities, which are promising for comprehensive electromagnetic defense in both military and civilian fields.

Abstract

The rapid development of wireless communication and infrared (IR) detection technologies has generated an increasing demand for large-size high-performance wearable electromagnetic interference (EMI) shielding and IR stealth textiles. Herein, meter-scale MXene/graphene oxide (MG)@monstera nanocellulose (MC) core-shell nanofiber textiles are fabricated for the first time using a multi-stage cryogenic drying-assisted coaxial wet spinning assembly strategy, with MG as the conductive composite core and MC as the organic skeleton shell. The highly aligned shell and dense core endow the nanofibers with a great toughness of ≈39.6 MJ m−3, a strong strength >≈180 MPa, and a high conductivity of 6.4 × 103 S m−1. The textiles exhibit unprecedented ultra-broadband EMI shielding performance covering gigahertz and terahertz bands, with optimal shielding effectiveness up to 84 and 85 dB in the band of 8.2–26.5 GHz and 0.3–1.5 THz, respectively, at only 185 µm thick. Superb IR stealth performance in the near- and mid-IR ranges is also achieved, benefitting from their good heat resistance and low IR emissivity. Furthermore, the textiles also demonstrate excellent dyeability, flame retardancy, Joule heating, and stress-sensing properties. Such scalable prepared core-shell nanofiber textiles with superior comprehensive performance have broad application prospects in future smart wearable protective devices.

Novel polyimide-ionene hybrids that exhibit desirable alcohol processability, conductivity, transparency, and metal/semiconductor interface modification ability are furnished by melding pyromellitic diimides into ionene backbones. These merits render them universal cathode interlayer materials with outstanding thickness tolerance, leading to not only highly efficient and stable opaque devices but also high-performance semitransparent devices even when pairing with low-cost Cu electrodes.

Abstract

The contradiction between high transmittance and favorable conductivity poses a great challenge in developing effective cathode interlayer (CIL) materials with sufficient thickness tolerance, which hinders the further advancement of organic solar cells (OSCs). Herein, a completely new class of alcohol processable polyimide-ionene hybrids (PIIHs) is proposed by melding pyromellitic diimide (PMD) subunits into imidazolium-based ionenes backbone covalently. These PIIHs, named PMD-DI and PMD-PD, boast high transparency, suitable energy levels, and decent conductivity. A higher PMD content endows PMD-PD with improved work function tunability, electrical properties, and crystallinity, enabling PMD-PD as CIL material with excellent thickness-insensitive characteristics, while simultaneously improving device stability significantly. Furthermore, PMD-PD also exhibits good compatibility with various electrodes and active layers, offering solar cell efficiencies of up to 19.91% and 19.29% with Ag and Cu cathodes, respectively. More importantly, the application of PMD-PD can improve the performance of semi-transparent OSCs without losing transmittance, thereby drastically enhancing the light utilization efficiency to 4.04% with an ultrathin, low-cost Cu cathode, that competes with leading optical modulation-free semitransparent OSCs with expensive Ag cathodes. This work opens a pathway to realize transparent and conductive interlayers by strategic molecular design, leading to highly efficient, stable, and cost-effective OSCs suitable for diverse applications.

Biological nanopores are highly promising tools for single-molecule biosensors, but the fragile supporting lipid membranes is a major bottleneck. An alternative hybrid membrane is presented, comprising phospholipids and block co-polymers, that can be functionalized by a broad variety of nanopores for single-molecule sensing. Crucially, the hybrid membrane provides substantially increased stability to harsh conditions, providing new opportunities for nanopore-based biosensors.

Abstract

Biological nanopores are powerful tools for single-molecule detection, with promising potential as next-generation biosensors. A major bottleneck in nanopore analysis is the fragility of the supporting lipid membranes, that easily rupture after exposure to biological samples. Membranes comprising PMOXA-PDMS-PMOXA (poly(2-methyloxazoline-b-dimethylsiloxane-b-2-methyloxazoline)) or PBD-PEO (poly(1,2-butadiene)-b-poly(ethylene oxide)) polymers may form robust alternatives, but their suitability for the reconstitution of a broad range of nanopores has not yet been investigated. Here, PBD-PEO membranes are found to be highly robust toward applied voltages and human serum, while providing a poor environment for nanopore reconstitution. However, hybrid membranes containing a similar molar ratio of PBD11PEO8 polymers and diphytanoyl phosphatidylcholine (DPhPC) lipids show the best of both worlds: highly robust membranes suitable for the reconstitution of a wide variety of nanopores. Molecular dynamics simulations reveal that lipids form ≈12 nm domains interspersed by a polymer matrix. Nanopores partition into these lipid nanodomains and sequester lipids, possibly offering the same binding strength as in a native bilayer. Nanopores reconstituted in hybrid membranes yield efficient sampling of biomolecules and enable sensing of high concentrations of human serum. This work thus shows that hybrid membranes functionalized with nanopores allow single-molecule sensing, while forming robust interfaces, resolving an important bottleneck for novel nanopore-based biosensors.

Zinc anodes face severe instability under extreme conditions of high current density, high areal capacity, and high depth of discharge (DOD) due to severe concentration polarization caused by the imbalance between Zn2⁺ consumption and transfer rates. To overcome this, a nanofluid layer is introduced to rapidly absorb Zn2⁺ and regulate interfacial ion transport, effectively mitigating polarization and enabling stable zinc deposition. This work provides key insights into interfacial engineering for next-generation high-performance zinc metal batteries.

Abstract

The commercialization of zinc metal batteries aims at high-rate capability and lightweight, which requires zinc anodes working at high current density, high areal capacity, and high depth of discharge. However, frequent zinc anode fades drastically under extreme conditions. Herein, it is revealed that the primary reason for the anode instability is the severe concentration polarization caused by the imbalanced consumption rate and transfer rate of Zn2+ under extreme conditions. Based on this finding, a nanofluid layer is constructed to rapidly absorb Zn2+ and mitigate the polarization induced by the nonlinear transport of interfacial ions. The modified zinc anode sustains at extreme conditions for over 1573 h (40 mA cm−2, 40 mAh cm−2, DOD = 75.97%) and 490 h (100 mA cm−2, 100 mAh cm−2, DOD = 90.91%), and achieving an unprecedented cumulative capacity of 62.92 Ah cm−2. This work offers both fundamental and practical insights for the interface design in energy storage devices.

This review aims to highlight the effect of electrolyte regulation on alleviating issues on the cathode side in aqueous ZIBs. The recent advances of electrolyte regulation strategies are present, with a comprehensive discussion and summary of regulation mechanisms, which can provide guidance to develop novel and multifunctional electrolytes for next-generation aqueous ZIBs.

Abstract

Enhancing cathodic performance is crucial for aqueous zinc-ion batteries, with the primary focus of research efforts being the regulation of the intrinsic material structure. Electrolyte regulation is also widely used to improve full-cell performance, whose main optimization mechanisms have been extensively discussed only in regard to the metallic anode. Considering that ionic transport begins in the electrolyte, the modulation of the electrolyte must influence the cathodic performance or even the reaction mechanism. Despite its importance, the discussion of the optimization effects of electrolyte regulation on the cathode has not garnered the attention it deserves. To fill this gap and raise awareness of the importance of electrolyte regulation on cathodic reaction mechanisms, this review comprehensively combs the underlying mechanisms of the electrolyte regulation strategies and classifies the regulation mechanisms into three main categories according to their commonalities for the first time, which are ion effect, solvating effect, and interfacial modulation effect, revealing the missing puzzle piece of the mechanisms of electrolyte regulation in optimizing the cathode.

This study investigates bias-induced structural transformations in 1T-TiSe2 devices, focusing on the transition from the 1T metallic phase to the distorted 1Td phase and ultimately to an orthorhombic Ti9Se2 conducting phase. Using ex-situ and in-situ TEM, dynamic structural changes and insights into the effect of thickness on phase transitions, providing valuable information for CDW-based device applications, are revealed.

Abstract

Metallic transition metal dichalcogenides (MTMDCs) are of significant attention for various electronic applications due to their anisotropic conductivity, high electron mobility, superconductivity, and charge-density-waves (CDW). Understanding the correlations between electronic properties and structural transformations is crucial. In this study, a bias-induced structural transformation in vertical CDW-based 1T-TiSe2 devices, transitioning from a 1T metallic phase to a distorted transition 1Td phase and subsequently to an orthorhombic Ti9Se2 conducting phase, is reported. Using ex-situ and in-situ biasing transmission electron microscopy, dynamic structural changes, while electron energy loss spectroscopy analysis revealed valence state modifications in Ti and Se within the Ti-rich layer after biasing, are observed. In addition, the effect of varying 1T-TiSe2 thickness on the maximum current value is investigated. These observations reveal that increased thickness requires higher voltage to induce phase transitions. These insights contribute to understanding the structural and electronic dynamics of 1T-TiSe2, highlighting its potential as a promising material for future CDW-based device applications.

Influence Functions

When attempting to understand the behaviour of a machine learning model, a common question is: how did the training examples contribute to a model output? Which examples contributed the most? This can also be framed as a counterfactual question: how would the final model outputs change upon removal of some examples from the training set? The goal of training data attribution (TDA) methods like influence functions, which will be the subject of this talk, is to answer precisely this question. In this talk, we will give an introduction to influence functions, discuss challenges and approaches to scalability, and give examples of practical applications. We will show that solving the aforementioned data attribution problem can be extremely useful. It can help identify pernicious data – from mislabelled examples, data responsible for undesirable behaviours (e.g. profanity or explicit content) through to data poisoning attacks. Influence functions can help understand memorisation in neural networks, providing mitigations to privacy and copyright concerns, along with fair data valuation. Influence functions can answer the above TDA problem efficiently without retraining, using only the local information about the training loss function around the final model parameters. They have been successfully used for these tasks for models ranging from 50 billion parameter Large Language Models to modern diffusion models.

Teams link available upon request (it is sent out on our mailing list, eng-mlg-rcc [at] lists.cam.ac.uk). Sign up to our mailing list for easier reminders via lists.cam.ac.uk.

• Speaker: Adrian Goldwaser, Bruno Mlodozeniec, Runa Eschenhagen, University of Cambridge
• Wednesday 05 March 2025, 11:00-12:30
• Venue: Cambridge University Engineering Department, CBL Seminar room BE4-38..
• Series: Machine Learning Reading Group @ CUED; organiser: .

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Ultra-small silver nanoparticles are formed in situ and activated in an amidoxime-modified polymer of intrinsic microporosity to fabricate a metallic nanocomposite membrane for C2H4/C2H6 separation. The activated silver nanoparticles promote C2H4 transport and effectively enhance C2H4/C2H6 separation selectivity, resulting in an outstanding membrane separation performance with C2H4 permeability of 322.1 barrer and C2H4/C2H6 selectivity as high as 8.8.

Abstract

The separation of C2H4 and C2H6 is a critical yet energy-intensive operation in the petrochemical industry. Gas separation membranes offer energy-efficient alternatives, but their effectiveness is hindered by the similar physical properties of C2H4 and C2H6. Here, a metallic nanocomposite membrane (MNM) comprising ultra-small Ag nanoparticles embedded in an amidoxime-modified polymer of intrinsic microporosity (AOPIM-1) is reported for highly efficient C2H4/C2H6 separation. The microporous structure of AOPIM-1, combined with anchoring groups (amidoxime groups) inside the microcavities, enables size-controlled growth of Ag nanoparticles with ‒≈3 nm diameter, which maximizes the contact with ethylene molecules. The amidoxime groups as electron acceptors effectively enrich the positive charge on the surface of Ag nanoparticles. The activated Ag form reversible complexes with ethylene molecules endowing them with preferential affinity over ethane. The resulting Ag nanocomposite membrane demonstrates a ≈10-fold increase in C2H4 permeability, reaching 322.1 barrer, and a ≈3-fold increase in C2H4/C2H6 selectivity, reaching 8.8. The comprehensive separation performance is superior over all the polymer membranes and mixed matrix membranes reported so far. The MNMs also demonstrate stable mixed gas separation performance under elevated feed gas pressures. This study provides valuable insights into designing and fabricating polymer membranes with high C2H4/C2H6 separation performance.

A Co single-atom catalyst (Co-N₄) enhances Cl₂ adsorption and lowers LiCl reaction barriers in Li-Cl₂ batteries. The Li-Cl₂@Co-NC battery exhibits >600 cycles at 1500 mA g⁻¹ at room temperature and 650 cycles at 500 mA g⁻¹ at −40 °C, with a 0.6 V reduction in polarization voltage. This strategy delivers high-performance Li-Cl₂ batteries with wide temperature adaptability.

Abstract

Lithium-chlorine (Li-Cl2) secondary batteries are emerging as promising candidates for high-energy-density power sources and an extensive operational temperature range. However, conventional electrode materials suffer from weak adsorption for chlorine gas (Cl2) and low conversion efficiency of lithium chloride (LiCl), leading to significant loss of chlorine-based active materials. This issue hampers the cyclability of Li-Cl2 batteries. In this work, it is demonstrated that synergistic Cl2 adsorption on the electrode surface and the energy barrier for LiCl reactions are crucial for enhancing Cl2/LiCl conversion efficiency. Consequently, a cobalt (Co) single-atom site catalyst with a Co-N4 coordination environment has been developed, which significantly diminishes the transformation barrier of solid LiCl particles into Cl2 and concurrently enhances the chemical adsorption of Cl2, facilitating uniform nucleation of LiCl. As a result, the Li-Cl2@Co-NC battery developed has achieved a 0.6 V reduction in polarization voltage under high current densities, effectively addressing the issue of low conversion efficiency between Cl2 and LiCl. At room temperature, the Li-Cl2@Co-NC battery achieves over 600 cycles at 1500 mA g−1; At −40 °C, it reaches 650 cycles at 500 mA g−1. The research overcomes the cycle stability barrier in high-current Li-Cl2 batteries and offers a strategy for batteries with a wide temperature range and long cycle life.

Nature Materials, Published online: 04 March 2025; doi:10.1038/s41563-025-02177-y

Non-fullerene acceptors help organic solar cells achieve high performance, transforming organic photovoltaics into a useful technology.

Nature Materials, Published online: 04 March 2025; doi:10.1038/s41563-025-02160-7

Derya Baran, an associate professor at King Abdullah University of Science and Technology (Department of Materials Science and Engineering), talks to Nature Materials about the progress of laboratory-to-fabrication for organic photovoltaics

Nature Materials, Published online: 04 March 2025; doi:10.1038/s41563-025-02161-6

Jenny Nelson, a professor at Imperial College London (Department of Physics), talks to Nature Materials about recent research advances in organic photovoltaics.

Nature Materials, Published online: 04 March 2025; doi:10.1038/s41563-025-02163-4

The benchmark fullerene-based electron-transporting materials (ETMs) for inverted perovskite solar cells are often limited by thermal evaporation or stability issues. Here the authors report solution-processable non-fullerene ETMs with improved device stability and efficiency.