Helmholtz-Institute Ulm

ABSTRACT Lithium dendrite formation and low ionic conductivity of solid polymer electrolytes (SPEs) are the main challenges that plague the long cycle life and capacity retention of lithium‐metal batteries. To address these challenges, poly(crown ether piperidinium) (PCEP)/poly(ethylene oxide) (PEO) based SPEs with synergistic regulation of cation−anion functions are designed and prepared. The crown ether moieties within PCEP enable coordination with Li + , reducing the Li + coordination number and enhancing the ionic conductivity of SPEs to 4.2 × 10 −4 S cm −1 at 60°C. Concurrently, piperidinium units effectively immobilize TFSI − ions through electrostatic adsorption, resulting in an elevated Li + transference number (0.7) and a concomitant reduction in lithium dendrite growth. Consequently, a coin cell using a PCEP‐based SPE with a lithium iron phosphate cathode displayed a high cycle life of 2000 cycles at 1.0C with a commendable final discharge capacity of 117.9 mAh g −1 , corresponding to 79.4% capacity retention. Furthermore, lithium−sulfur coin cells utilizing PCEP‐based SPEs exhibit a specific discharge capacity of 671.8 mAh g −1 after 80 cycles at 0.2C, corresponding to 80.7% of the initial capacity, outperforming SPEs without PCEP. This research work introduces a synergistic cation−anion regulation strategy for the advancement of solid‐state energy conversion/storage systems.

Abstract In the study of complex systems, the intricate interdependence among individual components leads to emergent properties that cannot be solely attributed to the properties of the components themselves. This principle is central to compositionally complex materials (CCMs), where interactions between different elements introduced into the structure result in unprecedented material properties. The emergence of high entropy materials (HEMs) in 2004 further increase complexity by achieving high configurational entropy (Sconfig) leading to unique properties and stabilizing phases that would otherwise undergo demixing due to positive reaction enthalpy. HEMs and CCMs represent an emerging family of materials where multiple principal elements occupy equivalent crystallographic sites. This atomic architecture gives rise to extraordinary properties such as tailorable electronic structures, lattice distortion effects, and synergistic interactions, resulting from their vast, near-infinite combinatorial space. Although the field is still in its infancy, early discoveries highlight their disruptive potential, particularly in energy technologies where robustness and durability are critical. Their exceptional thermal stability, corrosion resistance, and electro-chemo-mechanical durability position HEMs and CCMs as game-changers for applications demanding resilience under harsh operating conditions, such as batteries, fuel cells, and hydrogen storage systems. Beyond performance advantages, CCMs challenge traditional materials discovery frameworks. Their extensive design space makes conventional trial-and-error approaches impractical, creating an ideal platform for deploying AI-driven high-throughput computational screening, multiscale modeling, and autonomous experimental workflows. This convergence of complexity and innovation offers unprecedented opportunities to accelerate the identification of next-generation energy materials. This roadmap compiles insights from leading experts in the field of CCMs across key energy domains, including electrochemical storage, catalysis, thermoelectrics, and turbomachinery. Their contributions critically assess the current state of this material family highlighting unresolved scientific challenges, technological barriers, and the key advancements needed to move beyond the current state-of-the-art. Special emphasis is placed on combinatorial synthesis and high-throughput approaches and their potential to trigger exponential development of this emerging family of materials. Focused on energy applications, this roadmap provides a comprehensive overview of a time-critical topic, emphasizing the need for material innovation and joint efforts from academia and industry.

Interlayer engineering is widely used to improve charge storage in layered transition metal dichalcogenides, yet most studies rely on nanosized materials where the effects of interlayer expansion and particle downsizing are intertwined. Here, molecular pillaring is translated to bulk molybdenum disulfide (MoS2) using a top-down strategy. Chemical pre-reduction with butyllithium enables exfoliation and restacking in the presence of hexanediammonium (HDA) molecules, forming a pillared MoS2-HDA structure with an expanded interlayer spacing of 0.98 nm while preserving the bulk particle morphology and specific surface area. Electrochemical analysis reveals that improved rate capability primarily originates from the chemical activation associated with the pre-reduction step rather than from interlayer expansion itself. Operando X-ray diffraction and electrochemical dilatometry show that bulk MoS2 undergoes solvent co-intercalation in diglyme electrolyte, leading to pronounced lattice expansion and electrode swelling. In contrast, pillared MoS2-HDA suppresses solvent cointercalation despite its larger interlayer spacing, demonstrating that interlayer expansion alone does not dictate solvent co-intercalation in layered electrodes.

Issuers of sustainability-linked bonds (SLBs) face higher coupons or other negative consequences if a key performance indicator misses a sustainability target. Within a Merton-type model, we derive closed-form default probabilities for debt structures that incorporate SLBs and compare these probabilities to those associated with conventional debt. The comparison yields a critical correlation threshold ρ ∗ : If the correlation between asset values and the key performance indicator exceeds ρ ∗ , the SLB strictly lowers default risk. In typical cases that we examine, the correlation threshold is close to zero, and changes in default probabilities are rather small. • Sustainability-linked bonds (SLBs) penalize unmet sustainability targets. • We determine default probabilities when debt structures include SLBs. • The asset–key performance indicator (KPI) correlation affects outcomes. • If the asset–KPI correlation exceeds a threshold, SLBs reduce default risk. • Numerical results show that changes in default probabilities are small.

HighlightsDifferences between small lab cells, mid-sized, and large cells with increasing TRLImpedance decreases by three orders of magnitude from coin to large cellsHeating power increases by a factor of 102 to 105 from coin to large cellsSpecific capacities (material level) decrease by a factor of ∼3 to ∼5 (cell level)Differences must be considered to prevent misinterpretation of small cell results

Research and development of non-aqueous electrolyte solutions are essential for practical advancement towards the production of high-energy lithium metal batteries (LMBs). An ideal LMB electrolyte solution should enable highly efficient, uniform and prolonged lithium metal plating and stripping, preserve the electrodes' electro(chemo)mechanical properties and ensure compatibility with all cell components. However, despite extensive research efforts, scientists have yet to achieve an electrolyte design that meets these requirements simultaneously. Here, by examining the nanoengineering aspects of various non-aqueous electrolyte solution designs, we elucidate the understanding of the nanoscale physicochemical and electrochemical processes taking place in LMBs, which are mainly governed by the thermodynamic and kinetic properties of the electrolyte system. We also explore emerging research directions and propose an accelerated, iterative framework that integrates nanoengineering principles with machine learning, high-throughput computation and experimentation to facilitate the development of next-generation non-aqueous electrolyte solutions for practical LMBs.

The growing resistance of Enterobacterales to last-resort antibiotics such as carbapenems puts a significant burden on healthcare systems, also due to plasmids driving a rapid spread of carbapenem resistance. We here evaluate the use of long-read nanopore sequencing to investigate carbapenem resistance dynamics and the role of plasmid transfers and environmental reservoirs in the hospital setting. Over 13 months, routine clinical diagnostics identified recurring isolates of carbapenem-resistant Citrobacter species carrying Klebsiella pneumoniae carbapenemases (KPCs) and/or OXA-48-like carbapenemases from patient screening and hospital drain samples. While routine diagnostic approaches provided limited insights into the carbapenem resistance dynamics, we show that near-complete de novo assembly of chromosomes and plasmids by long-read nanopore sequencing allowed for high-resolution strain identification, plasmid profiling, and antibiotic resistance gene detection. Notably, genomically nearly indistinguishable Citrobacter freundii of the high-risk sequence type ST91 genomes were recovered from screening samples collected in the same hospital room 1 year apart. We further provide evidence of a KPC-2-encoding IncN plasmid that is likely to have spread across bacterial species and between patient and drain isolates, which emphasizes the role of contaminated drains in the persistence and dissemination of antimicrobial resistance within the hospital environment. Overall, this study demonstrates the value of long-read nanopore sequencing for uncovering the complex dynamics of carbapenem resistance spread and persistence in the hospital setting and its potential implications for infection prevention and control.

ABSTRACT The development of wide‐temperature gel polymer electrolytes (GPEs) represents a promising strategy for enhancing the extreme environment tolerance of lithium‐metal batteries (LMBs), which requires simultaneously optimizing Li + transport kinetics at low temperatures and maintaining the thermal and mechanical stability. This work addresses the intrinsic limitations of conventional GPEs by employing a molecular engineering strategy that achieves molecular‐scale hybridization of organic and inorganic units. Specifically, a fluorinated hybrid gel polymer electrolyte (FHPE) is fabricated through the in situ crosslinking polymerization of trifluoroethyl acrylate (TFEA) and acryloxypropyl polyhedral oligomeric silsesquioxane (Acry‐POSS) within 2,2‐difluoroethyl acetate (DFEA). The FHPE displays high Li + conductivity (3.54 × 10 −4 S cm −1 at −30°C), broad electrochemical stability window (>4.7 V), and remarkable mechanical strength (58.7 MPa). Moreover, the FHPE promotes the formation of LiF‐rich interphases on the LiCoO 2 cathode and lithium metal anode, thereby effectively mitigating dendrite growth and interfacial side reactions. Consequently, FHPE‐based Li/Li coin cells stably cycle for 1500 h at 0.3 mA cm −2 and −30°C, while Li/LiCoO 2 coin cells exhibit 86.7% capacity retention after 200 cycles at −30°C and 77.9% after 400 cycles at 60°C. Furthermore, Li/FHPE/LiCoO 2 pouch cells exhibit stable operation during nail penetration tests, thereby confirming their exceptional safety.

Sodium-ion batteries (SIB) have recently emerged as an alternative to current lithium-ion batteries (LIB), using low-cost and abundant raw materials. However, previous assessments have come to controversial results regarding their economic competitiveness, and the potential impacts of SIB on the wider energy system are still unexplored. This study combines a bottom-up cost modelling including future performance developments on material level for SIB with a global energy system model to obtain a comprehensive assessment of the potential impact of SIB on the global energy-industry transition until 2050. The results show that with recent cost developments and learning curves, batteries are no longer a cost-critical component in the energy system with projected utility-scale battery system capex of 28.5–51.9 €/kWh cap by 2050. SIB potentially outperform LIB on the medium term and are less prone to price spikes and supply shortages. Being a so-called drop-in technology, they could be produced on existing LIB production lines with only minor modifications. Therefore, concerns about supply shortages or price increases can be seen as resolved, since any disturbance in LIB supply would simply trigger a shift to SIB. The overall energy system structure remains virtually unaffected, with similar solar photovoltaic shares, but a shift in power-to-X processes operation. In this sense, electrochemical energy storage is not found to be a limiting factor for the global energy transition. Correspondingly, this work projects the possibly highest stationary battery demand published with a range of 67.9–106.5 TWh cap by 2050, above those in existing cost-optimised energy-industry system analyses. • Sodium-ion and lithium-ion battery cell cost modelling with current material cost • Thorough learning rate investigation and application for future cost estimation • Sodium-ion battery cells close to cost parity today, higher prospects for reduction • Cheaper batteries do not trigger more solar PV but battery capacity. • More battery capacity is used to run Power-to-X in higher load.

Nickel/zinc (Ni/Zn) batteries are a promising post‐lithium technology for stationary energy storage applications offering advantages in safety, environmental compatibility, and resource availability. Although this battery chemistry has been known for decades, the theoretical knowledge about its electrochemical processes remains limited. In order to gain a deeper understanding of the general cycling behavior and the underlying processes, but also specific phenomena intrinsic to zinc‐based cells such as zinc shape change, simulations based on a thermodynamically consistent, volume‐averaged continuum model are performed. A Ni/Zn prototype cell is used as a reference framework to provide a basis for modeling, parameter estimation, and systematic comparison between simulated and experimental cell behavior to enhance cyclability and performance.