• Energy Research

Abstract Carbon–polymer-composite bipolar plates (BPP) are suitable for fuel cell and flow battery applications. The advantages of both components are combined in a product with high electrical conductivity and good processability in convenient polymer forming processes. In a comprehensive techno-economic analysis of materials and production processes cost factors are quantified. For the first time a technical cost model for BPP is set up with tight integration of material characterization measurements.

AbstractAufgrund des steigenden Anteils erneuerbarer Energien in Deutschland wird eine Anpassung des stochastisch anfallenden, regenerativen elektrischen Stroms an den Bedarf notwendig. Eine Möglichkeit ist die Speicherung der Energie in Methan, wofür neben Wasserstoff auch eine Kohlenstoffquelle notwendig ist. In diesem Beitrag wird die Eignung von Prozessgasen der Stahlindustrie als Kohlenstoffquelle betrachtet, da diese in großen Mengen anfallen. Als Bewertungskriterium wird neben dem erreichbaren Wirkungsgrad auch die Qualität des erhaltenen Produktgases herangezogen. Es zeigt sich, dass Prozessgase der Stahlindustrie für die Zwischenspeicherung von Stromüberschüssen interessante Rohstoffe sind.

Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl− crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized.

The increasing adoption of lithium-ion battery cells in contemporary energy storage applications has raised concerns regarding their potential hazards. Ensuring the safety of compact and modern energy storage systems over their operational lifespans necessitates precise and dependable monitoring techniques. This research introduces a novel method for the cell-specific surveillance of prismatic lithium-ion cells, with a focus on detecting pressure increases through the surface application of a fiber Bragg grating (FBG) sensor on a rupture disc. Commercially available prismatic cells, commonly used in the automotive sector, are employed as test specimens and equipped with proven pressure and innovative FBG sensors. Encompassing the analysis capacity, internal resistance, and pressure (under elevated ambient temperatures of up to 120 °C), this investigation explores the thermal degradation effects. The applied FBG sensor on the rupture disc exhibits reversible and irreversible state changes in the cells, offering a highly sensitive and reliable monitoring solution for the early detection of abuse and post-abuse cell condition analysis. This innovative approach represents a practical implementation of fiber optic sensor technology that is designed for strain-based monitoring of prismatic lithium-ion cells, thereby enabling customized solutions through which to address safety challenges in prismatic cell applications. In alignment with the ongoing exploration of lithium-ion batteries, this research offers a customizable addition to battery monitoring and fault detection.

Abstract The vanadium redox flow battery (VFB) is one of the most promising stationary electrochemical storage systems. The reduction of system costs is a major challenge in the realization of its widespread application. The high complexity of this technology requires a close linking of technologic and economic aspects in system cost assessment. The present review provides an extensive literature analysis with a focus on techno-economic assessment of VFB. Considered materials, system designs and modelling approaches are assessed and compared in order to present and evaluate the current status of system cost assessment in a transparent way. Systems in a range of 2 kW–50 MW providing energy for up to 150 h are covered in literature resulting in an immense range of specific total system costs of 564–12931 € kW−1 or 89–1738 € (kWh)−1. Based on the data from the reviewed studies, guide values of 650 € (kWh)−1 and 550 € (kWh)−1 for installed VFB systems in a power range of 10–1000 kW providing energy for 4 h and 8 h respectively are derived from literature. Moreover, the relevance of precision in the definition of scope and components for meaningful results of techno-economic assessments of VFB systems is pointed out.

Abstract In the present contribution we investigated the influence of the acid pretreatment procedure of Nafion® 117 membranes on the resulting ionic conductivity by using electrochemical impedance spectroscopy. For this purpose, a setup allowing to measure the ionic conductivity at different temperatures, relative humidities, and contact pressures was developed. The state of protonation was determined by the ionic exchange capacity which is a measure of the amount of protonated sulfonic acid groups for the overall ionic exchange ability of the Nafion® membrane. The state of hydration was determined by water uptake and water vapor adsorption while structural observation was conducted by infrared spectroscopy. Additional thermophysical characterization was performed using differential scanning calorimetry. It was found that the pKa value and the concentration of the used acid for the pretreatment mainly influence the ion exchange capacity, whereas the temperature during pretreatment mainly influences the water uptake. The combination of high values for temperature, relative humidity and contact pressure leads to enhanced ionic conductivity of Nafion® membranes with a maximum value of 85.2 mS cm−1 for the membrane pretreated with HCl.

Abstract In the present work, a novel electrolyzer concept for alkaline water electrolysis (AEL) with a gas diffusion electrode (GDE) as anode, a conventional immersed porous cathode and a state-of-the-art Zirfon™ separator is presented and compared with a conventional electrolyzer setup. Due to the utilization of a GDE in this configuration, the electrolyte is only circulated through the cathode compartment which greatly simplifies the process. The influence of the catalyst composition and the enhanced electrode surface owing to the three-dimensional porous structure of the GDE are characterized and investigated regarding the electrode performance. Furthermore, process parameters like contact pressure and differential pressure are examined and optimized. The novel process concept with a GDE as anode reveals a similar cell potential compared to a classical electrolysis cell with a Ni/Fe-coated nickel foam anode up to 400 mA cm−2 at 353 K and 32.5 wt% KOH and also exhibits relatively good electrochemical stability over time.

Hello, you will find here the data used for analysis in the publication "Innovative Early Detection of High-Temperature Abuse of Prismatic Cells and Post-Abuse Degradation Analysis Using Pressure and External Fiber Bragg Grating Sensors" Attached is the complete electrical, thermal and pressure dataset measued by the Scienlab measurement and control module (Scienlab - SL60/200/12BT4C) as well as the parallel FBG measurement during operation (FiSens - X400) on the standard rupture disc of the tested large format prismatic cells. General hints: Sign convention for the current corresponds to positive values (I>0) equal to charging of the battery cell. Only raw data is provided without filtering or restriction of the data range. The mearsurement frequency for the optical data during the test B1 and O1 was set to 2 Hz. The exception to these rules are the reference ICA measurements which are resticted to the relevant cycle (2nd C/20 cycle) for comparison. Best regards André Hebenbrock

AbstractFischer–Tropsch (FT) synthesis is a complex three‐phase system with demanding requirements towards heat and mass transfer and may play an important role for future energy systems. The intensification of this process to exploit its maximum potential is only possible if the catalyst and reactor scale are considered at the same time. Thus, this Review addresses new concepts for improvement with an emphasis on originality as well as feasibility for the low‐temperature FT synthesis with cobalt catalysts as an example. The concepts are presented with respect to their impact on intensification and classified by the characteristic length scales at which they apply. On this basis, the single concepts are set in context for illustration of the overall improvement potential through a multiscale approach. The aim of this review is to propose a holistic view on the improvement of catalysts and reactors, which might also be transferred to other systems.