Electrode binder design for high-power, low-Pt loading and durable high temperature fuel cells
DOI: 10.1039/D4EE00646A, PaperHui Li, Peipei Zuo, Wenyi Wu, Gonggen Tang, Junkai Fang, Tongwen Xu, Zhengjin Yang
State-of-the-art high-temperature polymer electrolyte membrane fuel cells enabled by the phosphoric acid-doped polybenzimidazole material platform are promising for long-haul transport, but suffer from low output power, low Pt utilization, and...
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Fri 24 May 16:00: Title to be confirmed
Abstract not available
- Speaker: Sarah Waters, University of Oxford
- Friday 24 May 2024, 16:00-17:00
- Venue: MR2.
- Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.
Fri 03 May 16:00: Title to be confirmed
Abstract not available
- Speaker: Jerry Westerweel, TU Delft
- Friday 03 May 2024, 16:00-17:00
- Venue: MR2.
- Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.
Fri 17 May 16:00: PhD students' talks
Abstract not available
- Speaker: Speakers to be confirmed
- Friday 17 May 2024, 16:00-17:00
- Venue: MR2.
- Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.
Thu 02 May 14:00: The entanglement membrane in exactly solvable lattice models
Entanglement membrane theory is an effective coarse-grained description of entanglement dynamics and operator growth in chaotic quantum many-body systems. The fundamental quantity characterizing the membrane is the entanglement line tension. However, determining the entanglement line tension for microscopic models is in general exponentially difficult. We compute the entanglement line tension in a recently introduced class of exactly solvable yet chaotic unitary circuits, so-called generalized dual-unitary circuits, obtaining a non-trivial form that gives rise to a hierarchy of velocity scales with $v_E DU2 circuits, the entanglement line tension can be computed entirely, while for the higher levels the solvability is reduced to certain regions in spacetime. This partial solvability nevertheless constrains the dynamics inside the inaccessible region. Finally, we discuss a general framework of constructing lattice models with solvable dynamics. Our results shed light on entanglement membrane theory in microscopic Floquet lattice models and enable us to perform non-trivial checks on the validity of its predictions by comparison to exact and numerical calculations. Moreover, they demonstrate that generalized dual-unitary circuits display a more generic form of information dynamics than dual-unitary circuits.
- Speaker: Michael Rampp, MPIPKS
- Thursday 02 May 2024, 14:00-15:00
- Venue: TCM Seminar Room.
- Series: Theory of Condensed Matter; organiser: Gaurav.
Fri 10 May 16:00: Geometry and learning of dynamical systems
Abstract not available
- Speaker: Igor Mezic, UC Santa Barbara
- Friday 10 May 2024, 16:00-17:00
- Venue: MR2.
- Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.
Fri 14 Jun 16:00: Entrainment across a turbulent/turbulent interface
Abstract not available
- Speaker: Oliver Buxton, Imperial College London
- Friday 14 June 2024, 16:00-17:00
- Venue: MR2.
- Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.
Understanding Contact Electrification via Direct Covalent Bond Cleavage of Polymer Chains for Ultrahigh Electrostatic Charge Density
DOI: 10.1039/D4EE00395K, PaperHaiyan Fu, Jianliang Gong, Junhao Cao, Zehua Zhang, Zuchang Long, Bao Yang, Jianzhuang Chen, Yiwang Chen, Xiaoming Tao
The ancient and pervasively observed phenomenon of contact electrification (CE) is generally recognized to involve the transfer of electrons, ions, and materials between surfaces. However, compared to the mechanisms of...
The content of this RSS Feed (c) The Royal Society of Chemistry
Mon 29 Apr 14:00: Title to be confirmed (NOTE UNUSUAL DAY/TIME)
Abstract not available
(NOTE UNUSUAL DAY/TIME)
- Speaker: Michael Douglas (Center of Mathematical Sciences and Applications, Harvard University)
- Monday 29 April 2024, 14:00-15:00
- Venue: MR15 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.
Eliminating the Adverse Impact of Composition Modulation in Perovskite Light‐Emitting Diodes towards Ultra‐high Brightness and Stability
Excess ammonium halides as composition additives have been widely employed in perovskite light-emitting diodes (PeLEDs), aiming to achieve high performance by controlling crystallinity and passivating defects. However, an in-depth understanding whether excess organoammonium components affect the film physical/electrical properties and the resultant device instability is still lacking. Here, we point the trade-off between the performance and stability in high-efficiency formamidinium lead iodide (FAPbI3)-based PeLEDs with excess ammonium halides, and explore the underlying mechanism. Systematic experimental and theoretical studies reveal that excess halide salt-induced ion-doping largely alters the PeLEDs properties (e.g., carrier injection, field-dependent ion-drifting, defect physics, and phase stability). We then demonstrate a surface clean assisted cross-linking strategy to eliminate the adverse impact of composition modulation and boost the operational stability without sacrificing the efficiency, achieving a high efficiency of 23.6%, a high radiance of 964 W sr−1 m−2 (The highest value for FAPbI3 based PeLEDs), and a prolong lifetime of 106.1 h at large direct current density (100 mA cm−2), concurrently. Our findings uncovered an important link between excess halide salts and the device performance, providing a guideline for rational design of stable, bright, and high efficiency PeLEDs.
This article is protected by copyright. All rights reserved
Topological Defect‐regulated Porous Carbon Anodes with fast Interfacial and Bulk Kinetics for High‐rate and High‐energy‐density Potassium‐ion Batteries
Carbonaceous materials are regarded as one of the most promising anodes for potassium-ion batteries (PIBs), but their rate capabilities have been largely limited by the slow solid-state potassium diffusion kinetics inside anode and sluggish interfacial potassium ion transfer process. Herein, high-rate and high-capacity PIBs have been demonstrated by facile topological defect-regulation of the microstructure of carbon anodes. The carbon lattice of the as-obtained porous carbon nanosheets with abundant topological defects (TDPCNSs) holds high potassium adsorption energy yet low potassium migration barrier, thereby enabling efficient storage and diffusion of potassium inside graphitic layers. Moreover, the topological defects can induce preferential decomposition of anions, leading to the formation of high potassium ion conductive solid electrolyte interphase (SEI) film with decreased potassium ion de-solvation and transfer barrier. Additionally, the dominant sp2-hybridized carbon conjugated skeleton of TDPCNSs enables high electrical conductivity (39.4 S cm−1) and relatively low potassium storage potential. As a result, the as-constructed TDPCNSs anode demonstrates high potassium storage capacity (504 mA h g−1 at 0.1 A g−1), remarkable rate capability (118 mA h g−1 at 40 A g−1) as well as long-term cycling stability.
This article is protected by copyright. All rights reserved
Tue 23 Apr 13:00: POSTPONED to 30 April: The UK AI Safety Institute POSTPONED to 30 April: sorry for inconvenience
This talk will present an overview of efforts the UK government has been taking on AI over the past year, including the AI Research Resource, the AI Safety Summit, and with a focus on the AI Safety Institute (AISI). AISI is the world’s first state-backed organization focused on advanced AI safety for the public benefit, and is working towards this by bringing together world-class experts to understand the risks of advanced AI and enable its governance.
POSTPONED to 30 April: sorry for inconvenience
- Speaker: Nitarshan Rajkumar (University of Cambridge & UK AI Safety Institute)
- Tuesday 23 April 2024, 13:00-14:00
- Venue: Lecture Theatre 2, Computer Laboratory, William Gates Building.
- Series: Artificial Intelligence Research Group Talks (Computer Laboratory); organiser: Mateja Jamnik.
Ultra‐highly stiff and tough shape memory polyurea with unprecedentedenergy density by precise slight cross‐linking
Shape memory polymers (SMPs) have attracted significant attention and hold vast potential for diverse applications. Nevertheless, conventional SMPs suffer from notable shortcomings in terms of mechanical properties, environmental stability, and energy density, significantly constraining their practical utility. Here, inspired by the structure of muscle fibers, we report an innovative approach that involves the precise incorporation of subtle, permanent cross-linking within a hierarchical hydrogen bonding supramolecular network. This novel strategy has culminated in the development of covalent and supramolecular shape memory polyurea (CSSMP), which exhibits exceptional mechanical properties, including high stiffness (1347 MPa), strength (82.4 MPa), and toughness (312.7 MJ m−3), ensuring its suitability for a wide range of applications. Furthermore, it boasts remarkable recyclability and repairability, along with excellent resistance to moisture, heat, and solvents. Moreover, the polymer demonstrates outstanding shape memory effects characterized by a high energy density (24.5 MJ m−3), facilitated by the formation of strain-induced oriented nanostructures that can store substantial amounts of entropic energy. Simultaneously, it maintains a remarkable 96% shape fixity and 99% shape recovery. This delicate interplay of covalent and supramolecular bonds opens up a promising pathway to the creation of high-performance SMPs, expanding their applicability across various domains.
This article is protected by copyright. All rights reserved
Hydrogen Bonds Induced Ultra‐Long Stability of Conductive Π‐d Conjugated FeCo3(DDA)2 with High OER Activity
Conductive π-d conjugated metal-organic frameworks (MOFs) have attracted wide concerns in electrocatalysis due to their intrinsic high conductivity. However, the poor electrocatalytic stability is still a major problem that hinders the practical application of MOFs. Herein, we report a novel approach to enhancing the stability of MOF-based electrocatalyst, namely, the introduction of hydrogen bonds (H-bonds). Impressively, the π-d conjugated MOF FeCo3(DDA)2 exhibits ultra-high oxygen evolution reaction (OER) stability (up to 2000 h). The experimental studies demonstrate that the presence of H-bonds in FeCo3(DDA)2 is responsible for its ultra-high OER stability. Besides that, FeCo3(DDA)2 also displays a prominent OER activity (an overpotential of 260 mV versus RHE at a current density of 10 mA cm−2 and a Tafel slope of 46.86 mV dec−1). Density functional theory (DFT) calculations further indicate that the synergistic effect of the Fe and Co sites in FeCo3(DDA)2 contributes to its prominent OER performance. This work provides a new avenue of boosting the electrocatalytic stability of conductive π-d conjugated MOFs.
This article is protected by copyright. All rights reserved
Fri 26 Apr 13:00: Uniqueness of extremal black holes in de Sitter
Uniqueness theorems for black holes with a cosmological constant are only known in a few limited cases. In my talk I present a recent uniqueness theorem for the extremal Schwarzschild-de Sitter black hole within the class of analytic vacuum spacetimes with a positive cosmological constant containing a static extremal Killing horizon. The proof is based on establishing the uniqueness of transverse deformations to the near-horizon geometry at each order in the transverse parameter. I also present a generalisation to charged extremal black holes in de Sitter and discuss the analogous problem in the case of negative cosmological constant. The talk is based on 2309.04238 [gr-qc] and 2403.08467 [gr-qc].
- Speaker: Dávid Katona, The University of Edinburgh
- Friday 26 April 2024, 13:00-14:00
- Venue: Potter room/Zoom.
- Series: DAMTP Friday GR Seminar; organiser: Xi Tong.
Wed 24 Apr 11:00: Discussing the Stanford AI Report Zoom 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.
This week’s reading group session will discuss the recently released Stanford AI Report, available at https://aiindex.stanford.edu/report/
Zoom 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: Bruno Mlodozeniec, Julien Horwood, Runa Eschenhagen, University of Cambridge
- Wednesday 24 April 2024, 11:00-12:30
- Venue: Cambridge University Engineering Department, CBL Seminar room BE4-38..
- Series: Machine Learning Reading Group @ CUED; organiser: .
Wed 24 Apr 11:00: Discussing the Stanford AI Report Zoom 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.
This week’s reading group session will discuss the recently released Stanford AI Report, available at https://aiindex.stanford.edu/report/
Zoom 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: Bruno Mlodozeniec, Julien Horwood, Runa Eschenhagen
- Wednesday 24 April 2024, 11:00-12:30
- Venue: Cambridge University Engineering Department, CBL Seminar room BE4-38..
- Series: Machine Learning Reading Group @ CUED; organiser: .
Mon 22 Apr 14:00: Multiresolution Mesh Rendering Engine - Practicalities and Performance
[CESCG practice talk]
A multiresolution mesh is a structure that allows multiple levels of resolution of a mesh to be sampled in different regions. They are used to accelerate the construction of view-dependent Levels of Detail (LODs) for real-time rendering, generally for complex objects that may span large depths (e.g. terrain). Nanite, introduced in Unreal Engine 5, is an example of a full multiresolution pipeline. We describe our mesh-shader based multiresolution rendering engine in Vulkan, with two implementations to extract view dependent LODs. The first implementation is based on the approach established by Nanite. Our alternative implementation has no intermediate buffers at the cost of less fine-grained control over regions of the multires- olution we explore. We finally evaluate the two methods against each other and traditional LOD chains, emphasis ing practicality and performance.
Zoom link: https://cam-ac-uk.zoom.us/j/87633156881?pwd=ck9pR3YvdThSTHV4Ny8waXVQa3FYdz09
- Speaker: Maxwell Pettett, Univ. of Cambridge
- Monday 22 April 2024, 14:00-15:00
- Venue: SS03 - William Gates Building.
- Series: Rainbow Group Seminars; organiser: Rafal Mantiuk.
Tue 21 May 17:00: Self-translating science in early modern Europe: preliminary insights from the project Writing Bilingually, 1465–1700
Abstract not available
- Speaker: Sara Miglietti (Warburg Institute)
- Tuesday 21 May 2024, 17:00-18:30
- Venue: Seminar Room 1, Department of History and Philosophy of Science.
- Series: Early Science and Medicine; organiser: Dániel Margócsy.
Tue 07 May 17:00: Artists as futurists? On the history of durability in art and the making of the future
Abstract not available
- Speaker: Marjolijn Bol (Utrecht University)
- Tuesday 07 May 2024, 17:00-18:30
- Venue: Seminar Room 1, Department of History and Philosophy of Science.
- Series: Early Science and Medicine; organiser: Dániel Margócsy.