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Polymer materials offer controllable structure-dependent performances in separation, catalysis and drug release. Their molecular structures can be precisely tailored to accept Li+ for energy storage applications. Here the design of sp2 carbon-based polyphenylene (PPH) with high lithium-ion uptakes and long-term stability is reported. Linear-PPH (L-PPH) exceeds the performance of crosslink-PPH (C-PPH), due to the fact that it has an ordered lamellar structure, promoting the Li+ intercalation/deintercalation channel. The L-PPH cell shows a clear charge and discharge plateau at 0.35 and 0.15 V vs. Li+/Li, respectively, which is absent in the C-PPH cell. The Li+ storage capacity of L-PPH is five times that of the C-PPH. The reversible storage capacity is further improved to 261 mAh g−1 by functionalizing the L-PPH with the –SO3H groups. In addition, the Li-intercalated structures of C-PPH and L-PPH are investigated via near-edge X-ray absorption fine structure (NEXAFS), suggesting the high reversible Li+ –C C bond interaction at L-PPH. This strategy, based on new insight into sp2 functional groups, is the first step toward a molecular understanding of the structure storage-capacity relationship in sp2 carbon-based polymer.

X-ray computed tomography (CT) is an important tool for studying battery electrode microstructures but relies on robust segmentation for validity. Here, several approaches to applying accessible machine-learning segmentation software to segment open-source lithium-ion battery (LIB) electrode tomograms are followed to identify the optimised methodology that minimises variation in active material volume fraction quantification across three users. Iterative, manual training across seven cross-sectional slices (

Advanced batteries are critical to achieving net zero and are proposed within decarbonization strategies for transport and grid scale applications, alongside their ubiquitous application in consumer devices. Immense progress has been made in lithium battery technology in recent years, but significant challenges remain and new development strategies are required to improve performance, fully exploit power density capacities, utilize sustainable resources, and lower production costs. Suitable characterization techniques are crucial for understanding, inter alia, three dimensional 3D diffusion processes and formation of passivation layers or dendrites, which can lead to drastic capacity reduction and potentially to hazardous short circuiting. Studies of such phenomena typically utilize 2D or 3D imaging techniques, providing locally resolved information. 3D X ray imaging is a widely used standard method, while time lapse 4D tomography is increasingly required for understanding the processes and transformations in an operational battery. Neutron imaging overcomes some of the limitations of X ray tomography for battery studies. Notably, the high visibility of neutrons for light Z elements, in particular hydrogen and lithium, enables the direct observation of lithium diffusion, electrolyte consumption, and gas formation in lithium batteries. Neutron imaging as a non destructive analytical tool has been steadily growing in many disciplines as a result of improvements to neutron detectors and imaging facilities, providing increasingly higher spatial and temporal resolutions. Further, ongoing developments in diffraction imaging for mapping the structural and microstructural properties of battery components make the use of neutrons increasingly attractive. Here, we provide an overview of neutron imaging techniques, generally outlining advances and limitations for studies on batteries and reviewing imaging studies of lithium batteries. We conclude with an outlook on development methods in the field and discuss their potential and significance for future battery research

Traditionally, 1D volume-averaged continuum approaches are used to model Li-S battery performance at varying C-rates. For the first time, we present a working three-dimensional electrochemical model of a Li-S battery based on real electrode microstructure. In this study we evaluate the gaps between a volume-averaged 1D electrochemical model and a microstructurally resolved 3D image-based electrochemical model to accurately predict the effects of the localised heterogeneities present in Li-S cathodes on the battery performance at varying C-rates. The real microstructure of the commercial electrode was obtained using micro–X-ray computed tomography and used as a framework for an image-based 3D electrochemical model of the Li-S battery. The extent of heterogeneities present in the electrode architecture and the adequacy of using the representative elementary volume to capture the effect of complex electrode microstructure on the cell performance were analysed by mapping the 3D electrode microstructure. In this study, three-dimensional, microstructurally-resolved, image-based electrochemical models were developed on sub-volumes of the electrode to evaluate the effect of heterogeneous structure on the localised performance, which are further compared with the 1D model developed using the volume-averaged effective microstructural properties obtained from the X-ray CT image. Finally, the future modelling framework that would aid in optimising the S/C structure for improved and uniform cell performance is discussed.

Single-layer graphene (SLG) obtained by chemical vapor deposition is applied between membrane and electrodes by a wet chemical transfer method to study its effect on the performance and durability of polybenzimidazole membranes in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). After accelerated stress testing (AST), the membrane electrode assembly (MEA) loaded with SLG at different positions exhibits higher peak power density, lower electrode resistances, and larger electrochemical active surface area than pure polybenzimidazole membranes with high phosphoric acid doping level. The peak power density of the MEAs with both cathode and anode loaded with SLG is 480 mW cm-2 after AST, while those based on pure membranes is 249 mW cm-2. Lab-based X-ray micro-computed tomography combined with Raman spectroscopic mapping was applied for the first time to study the effect of SLG on controlling phosphoric acid leaching. In addition, samples containing SLG on an ultra-thin membrane (7.5 µm) were also tested to explore its influence on hydrogen crossover. After 100 h of galvanostatic discharging, the hydrogen crossover of samples loaded with single-layer graphene on the anode does not exceed 1.75 × 10−4 mol s-1, which is much lower than that of MEAs made using pure ultra-thin membranes (8.16 ×10−4 mol s-1).

A stable cathode-electrolyte interface (CEI) is crucial for aqueous zinc-ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode-electrolyte interface (CEI) in AZIBs. A water-soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion-dominated to capacitance-controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO

Homogenous, scalable, and uniform distribution of reactants at membrane-electrode assembly (MEA) level are critical to the performance of polymer electrolyte membrane (PEM) fuel cells. To achieve this, cathode flow fields were introduced that have fractal flow geometry, inspired by the air flow mechanism in lungs [1]. These were manufactured using direct metal laser sintering. Here, we discuss the design and characterisation of lung-inspired fuel cell flow plates using cheap and light printed circuit boards (PCBs) manufactured using computer numeric control (CNC) machining. X-Ray computed tomography (CT) scans of the developed fractal flow fields demonstrate a uniform and well aligned PCB plate assembly that results in a fractal hierarchy of flow channels, as shown in figure (1a) and (1b). Polarization performance at 70% reactant humidity and 45oC cell temperature for the fractal flow field was 12% higher than the performance of a single-serpentine, at 0.6V individual cell potential, as shown in figure (2).The cell temperature profile for the fractal flow field was more stable and uniform, compared to a rapid rise in profile of the single-serpentine one. The voltage decay measurements, at constant current density hold, indicate that voltages of fractal and single-serpentine flow fields vary within 2% and 6% of their initial voltage values, respectively, over a period of 6h continuous operation. Furthermore, Electrochemical Impedance Spectroscopic (EIS) measurements establish higher ohmic and mass transport resistances for the single-serpentine compared to the fractal flow field, at current densities ranging between 100mA/cm2 and 900mA/cm2. Keywords: Fractal, X-Ray CT, EIS,CNC, PCB, lung-inspired, hierarchical Reference: [1] P. Trogadas, J.I.S. Cho, T.P. Neville, J. Marquis, B. Wu, D.J.L. Brett and M.-O. Coppens, 2018, A lung-inspired approach to scalable and robust fuel cell design. Energy & Env. Sci. 11, 136-143. Figure 1

Polymer electrolyte fuel cells (PEFCs) are among the most promising energy conversion technologies for a broad range of applications and in recent years has shown tremendous advancements in terms of performance and durability, with wide-scale commercialisation imminent. However, new techniques are sought to optimise performance by understanding the internal workings of these devices. Understanding aspects of thermal and water management is of particular interest as they have a profound effect on both PEFC performance and durability, especially under dynamic load changes when used as power sources in automotive vehicles. Neutron imaging is a powerful technique for probing water distribution in PEFCs; however, beam-time access is limited, expensive and only available in a few sites worldwide. This work looks to develop a new diagnostic technique that is able to image water distribution in PEFCs in-operando using lab-based equipment. This non-invasive and non-destructive technique requires a thermal imaging camera and a periodic heat stimulus imposed on the fuel cell. By locking-in the camera to the frequency of the heat source stimulus, it is possible to isolate heat travelling through a fuel cell from the source. The internal fuel cell features (including presence of water) affect heat transfer properties and can consequently be detected by the camera. Furthermore, if the technique is applied over a range of perturbation frequencies, it can determine the spatial location and amount of liquid water within the fuel cell (figure attached). Figure 1