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With the purpose of investigating new polymeric materials as potential flow modifiers for their future application in enhanced oil recovery (EOR), a series of amphiphilic poly(di(ethylene glycol) methyl ether methacrylate

The performance of lithium-ion batteries is determined by the architecture and properties of electrodes formed during manufacturing, particularly in the drying process when solvent is removed and the electrode structure is formed. Temperature is one of the most dominant parameters that influences the process, and therefore a comparison of temperature effects on both NMC622-based cathodes (PVDF-based binder) and graphite-based anodes (water-based binder) dried at RT, 60, 80, 100 and 120 °C has been undertaken. X-ray computed tomography showed that NMC622 particles concentrated at the surface of the cathode coating except when dried at 60 °C. However, anodes showed similar graphite distributions at all temperatures. The discharge capacities for the cathodes dried at 60, 80, 100 and 120 °C displayed the following trend: 60 °C < 80 °C < 100 °C < 120 °C as C-rate was increased which was consistent with the trends found in adhesion testing between 60 and 120 °C. Focused-ion beam scanning electrode microscopy and energy-dispersive X-ray spectroscopy suggested that the F-rich binder distribution was largely insensitive to temperature for cathodes. In contrast, conductivity enhancing fine carbon agglomerated on the upper surface of the active NMC particles in the cathode as temperature increased. The cathode dried at RT had the highest adhesion force of 0.015 N mm−1 and the best electrochemical rate performance. Conversely, drying temperature had no significant effect on the electrochemical performance of the anode, which was consistent with only a relatively small change in the adhesion, related to the use of lower adhesion water-based binders.

Growth in the Li-ion battery market continues to accelerate, driven by increasing need for economic energy storage in the electric vehicle market. Electrode manufacture is the first main step in production and in an industry dominated by slurry casting, much of the manufacturing process is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding value to the electrode manufacturing value chain. Overcome the current barriers in the electrode manufacturing requires advances in material innovation, manufacturing technology, in-line process metrology and data analytics to improve cell performance, quality, safety and process sustainability. In this roadmap we present where fundamental research can impact advances in each stage of the electrode manufacturing process from materials synthesis to electrode calendering. We also highlight the role of new process technology such as dry processing and advanced electrode design supported through electrode level, physics-based modelling. To compliment this, the progresses in data driven models of full manufacturing processes is reviewed. For all the processes we describe, there is a growing need process metrology, not only to aid fundamental understanding but also to enable true feedback control of the manufacturing process. It is our hope this roadmap will contribute to this rapidly growing space and provide guidance and inspiration to academia and industry.

Performance properties of lithium-ion battery electrodes; capacity, rate and lifetime, are determined by the design of the coating composite microstructure. The internal pore structure and electronic networks for high coat weight graphite electrodes are manipulated through changes in the ink rheological properties, and through an syringe dispensing printing process. The rheological properties of a water-based, high viscosity graphite ink were optimised using a secondary solvent for the rheological requirements of a syringe dispensing method. The microstructure of high coat-weight battery electrodes produced from printing and tape cast methods were compared and the electrochemical performance evaluated. Cross sectional analysis of the slurry cast coatings showed improved component homogeneity, lower graphite alignment with 0.1% to 10% weight increase of the secondary solvent, with a corresponding change in tortuosity of the electrodes of 5.3–2.8. Improved cycle life is observed with a printed electrode containing an embedded electrolyte channel. Performance properties were elucidated through charge discharge, GITT and PEIS measurements. Improved electronic conductivities, exchange currents and diffusion coefficients were observed for the syringe deposited electrode. This digital deposition process for manufacturing electrodes shows promise for further optimisation of electrodes for long-life, high energy density batteries.

The vertical depth distributions of amine oxide surfactants, N,N-dimethyldodecyl amine N-oxide (DDAO) and N,N-dimethyltetradecyl amine N-oxide (DTAO), in poly(vinyl alcohol) (PVA) films were explored using neutron reflectometry (NR). In both binary and plasticized films, the two deuterated surfactants formed a single monolayer on the film surface with the remaining surfactant homogeneously distributed throughout the bulk of the film. Small-angle neutron scattering and mechanical testing revealed that these surfactants acted like plasticizers in the bulk, occupying the amorphous regions of PVA and reducing its glass-transition temperature. NR revealed little impact of plasticizer (glycerol) incorporation on the behavior of these surfactants in PVA. The surfactant molecular area in the segregated monolayer was smaller for DTAO than for DDAO, indicating that the larger molecule was more densely packed at the surface. Surface tension was used to assess the solution behavior of these surfactants and the effect of glycerol incorporation. Determination of molecular area of each surfactant on the solution surface revealed that the structures of the surface monolayers are remarkably consistent when water is placed by the solid PVA. Incorporation of glycerol caused a decrease of molecular area for DDAO and increase in molecular area for DTAO both in solution and in PVA. This suggests that the head group interactions, which normally limit the minimum area per adsorbed molecule, are modified by the length of the alkyl tail.

Medium or large amplitude oscillatory shear (M/LAOS) is sensitive to polymer chain structure, yet poses unsolved challenges for 'a priori' structural characterisation. In this letter, we present a MAOS protocol applied to near-monodisperse linear polymer melts, from which chain-stretch relaxation, a key structural feature, is clearly discernible. The third harmonics of MAOS frequency sweeps are decomposed into real and imaginary components and found to obey time-temperature superposition. The GLaMM molecular tube-based model of linear entangled melt rheology and structure, which has no free parameters, closely follows the form of our experimental results for the third harmonics and contains discriminatory features which depend only on the polymer's chain stretch relaxation time. Significantly, these third harmonic features occur at low frequency and are readily accessible with standard rheometers. For materials where phase transitions restrict the use of time temperature superposition, this method greatly increases the scope of rotational rheometry for structural analysis of polymers. Although the theory shows good qualitative agreement with experimental data, we find fundamental differences in magnitude and the frequency dependence of the third harmonics which must be resolved in order to fully understand the molecular basis of the stress response., Comment: V2 - Accepted version: 6 main pages with 4 figures + 8 supplemental pages with 8 figures

Exploiting graphene’s exceptional physical properties in polymer composites is a significant challenge because of the difficulty in controlling the graphene conformation and dispersion. Reliable processing of graphene polymer composites with uniform and consistent properties can therefore be difficult to achieve. We demonstrate distinctive regimes in morphology and nanocomposite properties, achievable through systematic control of shear rate and shear history. Remarkable changes in electrical impedance unique to composites of graphene nanoplates (GNPs) are observed. Low shear rates ≤ 0.1 s-1 break up the typical GNP agglomerates found in graphene composites, exfoliate the GNPs to fewer graphene layers and reduce orientation, enhancing electrical conductivi-ty in the composite materials. Whereas, at higher shear rates GNP orientation increases and the conductivity reduces by four orders of magnitude, as the graphene filler network is broken down. The structure of the composite continues to evolve, reflected in fur-ther changes in conductivity, after the shear force has been removed and the process temperature maintained. This work provides critical insights for understanding and controlling GNP orientation and dispersion within composites and will have important consequences in the industrial processing of graphene polymer composites via the informed design and choice of processing conditions.

The pressure dependencies of polymer viscosity and stress relaxation are an important but often overlooked aspect of the material processing and postprocessing properties. We show how these dependencies can be isolated in a single measurement and can be related to the characteristic relaxation times of the material. Using a multipass rheometer (a small volume double piston rheometer), a polystyrene melt was confined at 170 °C and pressure range 1–100 bar. The pressure drop over a contraction-expansion geometry and stress birefringence were monitored as a function of shear rate, shear history, and applied pressure. Relaxation times, extracted from the stress decays correspond closely to the Rouse and reptation times of the polymer and the contributions of each mode are determined by the relationship between the shear rate and relaxation times established from linear rheology. Increasing the applied pressure caused an increase in viscosity and the measured relaxation time, but no effect on relaxation times was observed with shear rate. The technique allows the extraction of relaxation data following deformation at high shear rates and pressures, conditions more akin to industrial processing than conventional shear rheology.