High efficiencies, wide operation range and rapid response time have motivated the recent interest in proton exchange membrane (PEM) electrolysis for hydrogen generation with surplus electricity. However, degradation at high current densities and the associated mechanism has not been thoroughly explored so far. In this work, membrane electrode assemblies (MEA) from different suppliers are aged in a commercial PEM electrolyzer (2.5 N m 3 H 2 h -1 ), operating up to 4 A cm -2 for more than 750 h. In all cases, the cell voltage (E cell ) decreases during the testing period. Interestingly, the cells with Ir-black anodes exhibit the highest performance with the lowest precious metal loading (1 mg cm -2 ). Electrochemical impedance spectroscopy (EIS) shows a progressive decrease in the specific exchange current, while the ohmic resistance decreases when doubling the nominal current density. This effect translates into an enhancement of cell efficiency at high current densities. However, Ir concurrently leaches out and diffuses into the membrane. No decrease in membrane thickness is observed at the end of the tests. High current densities do not lead to lowering the performance of the PEM electrolyzer over time, although MEA components degrade, in particular the anode.

This roadmap presents the transformational research ideas proposed by “BATTERY 2030+,” the European large‐scale research initiative for future battery chemistries. A “chemistry‐neutral” roadmap to advance battery research, particularly at low technology readiness levels, is outlined, with a time horizon of more than ten years. The roadmap is centered around six themes: 1) accelerated materials discovery platform, 2) battery interface genome, with the integration of smart functionalities such as 3) sensing and 4) self‐healing processes. Beyond chemistry related aspects also include crosscutting research regarding 5) manufacturability and 6) recyclability. This roadmap should be seen as an enabling complement to the global battery roadmaps which focus on expected ultrahigh battery performance, especially for the future of transport. Batteries are used in many applications and are considered to be one technology necessary to reach the climate goals. Currently the market is dominated by lithium‐ion batteries, which perform well, but despite new generations coming in the near future, they will soon approach their performance limits. Without major breakthroughs, battery performance and production requirements will not be sufficient to enable the building of a climate‐neutral society. Through this “chemistry neutral” approach a generic toolbox transforming the way batteries are developed, designed and manufactured, will be created.

Hybrid power plants consisting of a solid oxide fuel cell (SOFC) and a gas turbine show high electrical efficiencies, however require pressurisation of the SOFC to several bar. This paper presents a theoretical investigation of the pressure influence on SOFC performance and durability. A two‐dimensional elementary kinetic model is used to predict the performance of a single cell in the pressure range of 1–20 bar. The influence of pressure on thermodynamics, reaction kinetics, porous electrode diffusion, channel transport and efficiency is assessed. It was found that polarisation resistance decreases with increasing pressure due to increased diffusion through porous electrodes and a higher electrode surface coverage with reactant species. Furthermore, open‐circuit voltage increases slightly with pressure. As a consequence, power density and efficiency increase upon pressurisation with the strongest increase at low pressures between 1 and 5 bar. The influence of pressure on two typical degradation mechanisms, nickel oxidation and carbon deposition, is assessed using thermodynamic simulations. Pressurisation facilitates nickel oxidation whereas its effect on carbon deposition strongly depends on temperature.

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Diffusion coefficients are important parameters for the characterization of new electrode materials, but they are also essential for the study of cell aging and as input parameters in battery modeling. In this report, the applicability of the galvanostatic intermittent titration technique (GITT) on commercial cells is studied. A GITT protocol is applied on a set of commercial cells with graphite anodes and various cathode materials. The cell response is then compared with the ones of the individual electrodes, obtained in three-electrode and half-cell configurations. In particular, mostly due to the particular potential profile of graphite, the full cell GITT response corresponds to the anode and cathode response at low and high state of charge, respectively. Therefore, it is possible to estimate the diffusion coefficients of the individual electrodes by a simple experiment on commercial cells, although only in limited ranges of SOC. If the experiments are performed at different temperatures, it is also possible to determine the activation energies of the diffusion coefficients. In conclusion, GITT allows an estimation of the diffusivity data in commercial cells, and can be therefore used as fast analytical tool for the study of aging and for the modeling of lithium-ion batteries.

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