Aliphatic Anion Exchange Ionomers with Long Spacers and No Ether Links by Ziegler–Natta Polymerization: Properties and Alkaline Stability

In this work we report the synthesis of poly(vinylbenzylchloride-co-hexene) copolymer grafted with N,N-dimethylhexylammonium groups to study the effect of an aliphatic backbone without ether linkage on the ionomer properties. The copolymerization was achieved by the Ziegler–Natta method, employing the complex ZrCl4 (THF)2 as a catalyst. A certain degree of crosslinking with N,N,N′,N′-tetramethylethylenediamine (TEMED) was introduced with the aim of avoiding excessive swelling in water. The resulting anion exchange polymers were characterized by 1H-NMR, FTIR, TGA, and ion exchange capacity (IEC) measurements. The ionomers showed good alkaline stability; after 72 h of treatment in 2 M KOH at 80 °C the remaining IEC of 76% confirms that ionomers without ether bonds are less sensitive to a SN2 attack and suggests the possibility of their use as a binder in a fuel cell electrode formulation. The ionomers were also blended with polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde. The water uptake of the blend membranes was around 110% at 25 °C. The ionic conductivity at 25 °C in the OH− form was 29.5 mS/cm.

Electrochemical Performance of Na3V2(PO4)2F3 Electrode Material in a Symmetric Cell

A NASICON-based Na3V2(PO4)2F3 (NVPF) cathode material is reported herein as a potential symmetric cell electrode material. The symmetric cell was active from 0 to 3.5 V and showed a capacity of 85 mAh/g at 0.1 C. With cycling, the NVPF symmetric cell showed a very long and stable cycle life, having a capacity retention of 61% after 1000 cycles at 1 C. The diffusion coefficient calculated from cyclic voltammetry (CV) and the galvanostatic intermittent titration technique (GITT) was found to be ~10−9–10−11, suggesting a smooth diffusion of Na+ in the NVPF symmetric cell. The electrochemical impedance spectroscopy (EIS) carried out during cycling showed increases in bulk resistance, solid electrolyte interphase (SEI) resistance, and charge transfer resistance with the number of cycles, explaining the origin of capacity fade in the NVPF symmetric cell. Finally, the postmortem analysis of the symmetric cell after 1000 cycles at a 1 C rate indicated that the intercalation/de-intercalation of sodium into/from the host structure occurred without any major structural destabilization in both the cathode and anode. However, there was slight distortion in the cathode structure observed, which resulted in capacity loss of the symmetric cell. The promising electrochemical performance of NVPF in the symmetric cell makes it attractive for developing long-life and cost-effective batteries.

A parametric analysis of thermodynamic losses in an anode of a solid oxide fuel cell

In this paper, generation of thermodynamic losses in the micro-channels of a Solid Oxide Fuel Cell electrode is discussed. Diffusive-convective equation is implemented to compute local concentrations of reagents. The model accounts for both the Fick’s, and the Knudsen’s diffusion. For a number of cases the total losses are decomposed to isolate the contributions of the diffusion, the current conduction, and the chemical reaction irreversibilities.

Investigation of the Kerr effect on polarised light

A constructed Kerr cell with brass electrodes and liquid nitrobenzene was used for studying the Kerr effect on polarised light. Laser light was plane polarised and passed through an energised Kerr cell. The plane polarised light after travelling a path length equal to the cell electrode length in a birefringent medium, suffered optical retardance before passing through an analyser which then transmitted light of certain intensity to a photodiode. Data used were generated from experiments and theoretical considerations using Kerr’s law and Malus’ law. With crossed Polaroids, the Kerr cell behaved as an electro-optic shutter and the maximum light intensity transmitted rose steadily with increased phase difference to about 0.82. With parallel Polaroids, the maximum light intensity transmitted was higher and found to be 0.89 at zero phase difference. This value indicates a large phase delay and decreased to a non-zero value. At maximum electric field intensity, a ‘climbing’ of the nitrobenzene on the Kerr cell walls and electrodes was observed with more nitrobenzene attracted to the anode. The effect suspected to be of electrostatic origin may have been driven by the predominant ions in the nitrobenzene. Furthermore, the higher level of the nitrobenzene meniscus at the anode probably suggests that while the cathode injected carriers of negative charge into the liquid the injection of carriers from the anode was weaker. For better results, attention should be given to Polaroid quality, the purity of the liquid nitrobenzene and the length of the electrodes used.

Engineering Design of Battery Module for EVs: Comprehensive Framework Development Based on DFT, Topology Optimization, Machine Learning, Multidisciplinary Design Optimization and Digital Twins

Battery technology has been a hot spot for many researchers lately. Electrochemical researchers have been focusing on the synthesis and design of battery materials; researchers in the field of electronics have been studying the simulation and design of battery management system (BMS); whereas mechanical engineers have been dealing with structural safety and thermal management strategies for batteries. However, overcoming battery limitation in only one or two domains will not design an efficient battery pack as it requires an integrated framework. So far, there are few research studies that circumscribed all the multi-disciplinary aspects (cell material selection, cell-electrode design, cell clustering, state of health (SOH) estimation, thermal management, cell monitoring and recycling) simultaneously for battery packs in electric vehicles (EVs). This paper presents a holistic engineering design and simulation strategy for a future advanced battery pack and its parts by assimilating paradigmatic solutions for cell material selection, component design, cell clustering, thermal management, battery monitoring and recycling aspects of the battery and its components. The developed framework has been proposed based on DFT based cell material selection, topology design based cell-electrode design, machine learning (ML) based SOH estimation along with multi-disciplinary design optimization based liquid cooling system. The proposed framework also highlights the optimal configuration of cells using ML algorithms and multi-objective optimization of cell-assembly parameters. The role of digital twins for real-time and faster acquisition of data has been highlighted for the advanced and futuristic battery pack designs. Furthermore, preliminary investigation of robot assisted disassembly and recycling of battery packs has been summarized. Each proposed methodology has been discussed in detail, along with the advantages and limitations. Critical research orientations are also discussed in the end.