Power generation in space is currently dominated by expensive III–V multi-junction photovoltaic (PV) devices and cheap crystalline silicon (c-Si) PV devices. Both of these technologies degrade rapidly in proton-radiation-rich space environments, such as the Van Allen belt. The present study of cadmium selenide telluride- (CdSeTe-) based PV devices exposed to 150-to-1500 keV proton irradiation with fluences up to 9 × 10 ^13 cm ^−2 reveal a more radiation-hard alternative to III–V and c-Si PV technologies. We report on measurement and analysis of current density vs voltage (JV), external quantum efficiency (EQE), external radiative efficiency, and capacitance vs voltage (CV) characteristics. JV characteristics of As-doped CdSeTe devices show 80% remaining power conversion efficiency (PCE) relative to unexposed controls when exposed to 650 keV protons at a fluence of 10 ^12 cm ^−2 . Under these same irradiation conditions, Cu-doped CdSeTe devices demonstrate an even better 95% PCE retention compared with unirradiated control devices. Evidence of radiation-induced absorber p-type doping compensation is observed in the glass-side EQE at 0 V and CV characteristics of most of the irradiated CdSeTe:As devices, but clear compensation is evident only for the most heavily irradiated CdSeTe:Cu devices. Elevated blue-green photocurrent in the film-side 0 V EQE suggests a buried junction in the most heavily irradiated CdSeTe:As devices. Although CdSeTe:Cu devices are the more resilient of the CdSeTe structures, both CdSeTe-based technologies are radiation-hard when compared to c-Si and III–V multi-junction PV.
Abstract The search for electrochemical energy storage beyond lithium-ion batteries has yielded a broad landscape of alternative chemistries, yet most still adhere to the fundamental paradigm of cationic charge carriers. Anion-shuttle batteries, spanning dual-ion, chloride-ion, fluoride-ion, hydride-ion, bromide-ion, and polyiodide systems, represent a mechanistically distinct departure in which anions serve as the primary electroactive charge carriers, functioning as the exclusive shuttling species in fluoride-ion, chloride-ion, hydride-ion, and bromide-ion systems, while in dual-ion batteries anion intercalation at the cathode is coupled to simultaneous cation insertion or deposition at the anode. This Perspective provides a critical and comprehensive account of this emerging field, covering charge-transfer mechanisms, the development of electrode and electrolyte materials, and the failure modes that currently separate laboratory demonstrations from practical relevance. The thermodynamic case is compelling: fluoride-ion conversion chemistries project material-level theoretical energy densities exceeding 1,500 Wh kg-1 (and up to 588 Wh kg-1 at the stack level under techno-economic modeling), chloride-ion electrode screening identifies over 1,225 anode–cathode combinations with thermodynamic volumetric densities exceeding 2,000 Wh L-1; and dual-ion architectures sustain operating voltages of 4.5 to 5.5 V with near-unity coulombic efficiency over thousands of cycles. Yet three material challenges persist across all chemistries, regardless of anion identity: the kinetic penalties of anion solvation and interfacial desolvation, the electrochemical instability of the electrode–electrolyte interphase, and mechanical degradation arising from large volumetric strains during conversion cycling. We differentiate between limitations intrinsic to anionic charge-carrier physics and those addressable through rational materials design. Anion-shuttle batteries will not broadly displace lithium-ion technology, but their natural domain, grid-scale storage, high-temperature operation, and applications free from critical mineral dependencies, represent a strategically significant and scientifically compelling frontier.
Neutron diffraction has become an indispensable technique for probing structural evolution in energy materials and devices under realistic operating conditions. Compared to other scattering techniques such as X-ray or electron-based methods, using neutrons as a probe offers unique advantages. High sensitivity to light elements such as lithium and hydrogen especially in the presence of heavier elements, isotope discrimination, and a high penetration depth for non-destructive bulk analysis. These features enable characterization of complex, multi-component systems and allow experiments within functional devices without modification. This article provides a practical introduction to the application of neutron diffraction in the context of materials and devices for energy storage and generation, including principles of neutron–matter interactions, best practices for planning and executing experiments, considerations for sample environments and mitigating common measurement artefacts, and suggestions for data acquisition and analysis. Recent advances in neutron source intensity, detector technology, and automated data processing have significantly improved temporal resolution, enabling real-time tracking of phase transitions, lattice strain, and ion migration pathways during device operation providing mechanistic insights into energy materials and devices.
This review provides a comprehensive examination of non-destructive magnetic field-based imaging techniques for advanced diagnostics and monitoring of lithium-ion batteries. Two primary methodological approaches are systematically analyzed: magnetic resonance imaging methods, which detect state-of-charge via magnetic susceptibility variations, and direct magnetic field imaging techniques, which visualize internal current distributions. These methods enable non-invasive probing of key battery states and structural defects, offering a fundamental advantage over conventional monitoring techniques that rely on external electrical parameters. Their capacity for module-level, non-contact assessment also presents significant potential in applied scenarios, including the screening of retired batteries, demonstrating the potential to transition from laboratory characterization toward practical application. This review synthesizes recent advances, consolidates the current landscape of the technology, identifies major existing barriers, and provides forward-looking insights, ultimately aiming to advance the field toward intelligent battery management.
This paper presents the third version of the Efficiency Tables compiling the record efficiencies of materials considered as emerging inorganic absorbers for photovoltaic (PV) technologies. The materials collected in these Tables are selected based on their progress in recent years, and their demonstrated potential as future PV absorbers. The first part of the paper consists of an overview of the current status of emerging PV materials. The second section details the inclusion criteria used for the different technologies presented in the paper, the verification means used by the authors, and recommendations for measurement best practices. The third part compiles the highest world-class certified solar cell efficiencies, and the highest non-certified cases (some independently confirmed). This section includes a brief state-of-the-art for the different classes of materials defined in the paper. The final part summarizes the main conclusions of this third version of Emerging Inorganic Solar Cell Efficiency Tables, highlighting the most relevant progress published in the last two years.
Abstract Planar Sb₂S₃ solar cells, typically fabricated by spin-coating precursor solutions onto TiO₂/FTO (with or without CdS) superstrates, have achieved promising power conversion efficiencies, especially when paired with suitable hole transport layers (HTLs). While doped small-molecule HTLs such as Spiro-OMeTAD commonly enable record efficiencies above 5%, conductive polymers like poly(3-hexylthiophene-2,5-diyl) (P3HT) present a compelling alternative, offering high intrinsic hole mobility without the need for extrinsic dopants that can compromise chemical stability. However, the processing of P3HT—particularly the concentration in solution and resulting film thickness—often lacks systematic optimization. Here, we address this gap by investigating how P3HT concentration influences charge transport and recombination dynamics in Sb₂S₃ solar cells. Initially, we studied isolated P3HT films to elucidate the relationship between thickness, conductivity, and morphology/structure. Subsequently, we conduct a comprehensive electrical characterization of complete devices using electrochemical impedance spectroscopy, transient photovoltage, transient photocurrent, and intensity-modulated photocurrent and photovoltage spectroscopy. These techniques probe time- and frequency-resolved charge extraction and recombination processes, which are correlated with device performance metrics from J – V measurements. Our results demonstrate that P3HT thickness variations critically impact film morphology, carrier dynamics and overall photovoltaic performance. This work provides new insights into the operation of P3HT/Sb₂S₃ solar cells, informing strategies to optimize their performance towards efficiencies comparable to those achieved with doped Spiro-OMeTAD.
Abstract A new power conversion efficiency record of 16.6% was recently reported for thin-film devices based on Cu 2 ZnSn(S,Se) 4 (CZTSSe) off-stoichiometric polycrystalline absorber layers. Deviations from stoichiometry introduce intrinsic point defects that strongly affect the electronic properties of the material. In addition, Cu/Zn disorder is always present in these compounds and is discussed as a possible origin of band tailing. Cation mutation strategies can be used to minimize this disorder by inducing a structural change from kesterite—to stannite-type. One option is the substitution of Zn 2+ by Cd 2+ in CZTS. In the resulting solid solution, the end members crystallize in different structures: Cu₂ZnSnS₄ in the kesterite type and Cu₂CdSnS₄ in the stannite type. The crystal structure, cation distribution, and intrinsic point defect scenario of Cu₂(Zn 1−x Cd x )SnS₄ monograins were studied by neutron diffraction. For 0 ⩽ x ⩽ 0.38, the mixed crystals adopt the kesterite structure, with increasing Cu/ B I I disorder as Cd content increases. For 0.57 ⩽ x ⩽ 1.0, the material crystallizes in the stannite-type structure with a complete absence of Cu/ B I I disorder. The abrupt change in cation distribution indicates that the transition occurs within a narrow compositional range (0.38 < x < 0.57). Based on the tetragonal distortion ( c/2a ) and cation distributions at x = 0.38 and 0.57, the transition mechanism is likely similar to that in Cu₂(Zn 1−x Mn x )SnSe₄.
Capacity fade in Si-based porous anodes of Li-ion batteries has been mainly attributed to fracture of the Si particles. However, it was recently shown that even when the Si itself does not fracture, it is still not possible to retain a stable capacity, since significant cracking occurs in the binder. It is, therefore, vital to shift the focus to binder selection. In this work, it is shown that tannic acid (TA) is an effective binder for enhancing the mechanical stability of the Si porous electrodes, and hence increasing the electrochemical stability, since for nano Si-TA anodes, at 0.2 C, the initial discharge capacity was 2284 mAh g ^−1 and after 200 cycles it had dropped to 1279 mAh g ^−1 . Extended cycling was performed for 0.5 C, giving an initial capacity of 1414 mAh g ^−1 , which dropped to 440 mAh g ^−1 after 1000 cycles. The aforementioned capacity fade for nano-Si/tannic-acid based porous electrodes is significantly lower than that recorded when employing other binders such as alginate (850 mAh g ^−1 after 200 cycles), carboxymethyl cellulose (900 mAh g ^−1 after 100 cycles) and polyvinylidene fluoride (PVDF) (∼10 mAh g ^−1 after 50 cycles). Micron-sized Si-TA electrodes have also showcased an improved capacity retention of ∼1150 mAh g ^−1 after 200 cycles when compared with other binders such as block co-polymers (∼500 mAh g ^−1 after 100 cycles). Scanning electron microscopy revealed that the TA binders, in Si-based anodes, resulted in only a 50% increase in the electrode thickness over cycling, whereas PVDF gave a 183% overall electrode increase. The ability of TA to significantly suppress electrode thickness expansion during cycling reduced crack formation and hence improved capacity retention.
Abstract Alkali-metal cations enhance catalytic activity in CO 2 reduction reactions (CO 2 RRs) by providing an interface electric field enhancement effect and stabilizing CO 2 and CO 2 RR intermediates. Membrane electrode assemblies (MEAs) with zero-gap electrolyzers are expected to substantially improve selectivity and reaction rates by directly supplying CO 2 to the cathode and dramatically reducing resistance within the reactor. However, compared with the understanding of cation effects in conventional H-type reaction reactors, in which the cathode electrode is in contact with the electrolyte solution, the understanding of cation effects in MEA reactors is insufficient. In this study, we report that the C 2+ product selectivity of Cu-based catalysts is enhanced by pre-loading alkali-metal salts bearing hydrophobic counter-anions onto the cathode. Operando spectroscopic analysis suggests that alkali-metal cations increase the CO concentration on the catalyst surface and promote the formation of C–C coupling intermediate species. This method, which can enhance catalyst activity using a simple technique, is expected to significantly contribute to future catalyst and device development.
Abstract A strong societal and political drive is motivating the development and optimization of novel energy conversion and storage systems for decarbonization. The successful implementation of solid state devices such as fuel cells and secondary batteries depends, however, on achieving ambitious targets in terms of performance, reliability and cost competitiveness. Research and technology are addressing these needs through a holistic approach including exploration of new materials and nanoarchitectures, as well as system engineering. These significant efforts require the support of appropriate characterization tools capable of assessing nanometer-scale phenomena such as concentration profiles of ionic and electronic charges, local chemical compositions and their evolution over time across interfaces. This roadmap provides an overview of selected advanced characterization techniques for energy materials and devices. Specific focus is put on in situ/operando methods for probing electrochemical phenomena in real-time under realistic working conditions. Experts in the field provide an extensive review of the current state of the art in 2025 and the current and future challenges for the characterization of local chemistry and kinetics in the bulk of the material, in nanoarchitectures (e.g. thin films) and at the interfaces (e.g. grain boundaries, phase contacts, solid/liquid and solid/gas interfaces) . The aim is to provide a detailed guide to the techniques, describing opportunities and bottlenecks for their practical deployment and examples of successful applications. This roadmap provides an overview of selected advanced characterization techniques for energy materials and devices. Specific focus is put on in situ/operando methods for probing electrochemical phenomena in real time under realistic working conditions. Experts in the field provide an extensive review of the current state of the art in 2024 and the current and future challenges for the characterization of local chemistry and kinetics in the bulk of the material, in nanoarchitectures (e.g. thin films) and at the interfaces (e.g. grain boundaries, phase contacts, solid/liquid and solid/gas interfaces) . The aim is to provide a detailed guide to the techniques, describing opportunities and bottlenecks for their practical deployment and examples of successful applications.
Abstract A series of asymmetric Ru(II) complexes, comprising variable terpyridine and benzotriazole ligands, enables rapid ( k obs ∼ 1368–2840 s −1 ) and energy-efficient (overpotential ∼ 460–570 mV) CO 2 -to-CO electrochemical conversion. The intricate electronic exchange between ligand and metal core leads to the formation of key one-electron reduced species for stepwise CO 2 conversion, as revealed by spectroelectrochemical-UV–Vis and FTIR, EPR, and DFT studies.
Aqueous batteries represent a compelling frontier for safe and sustainable large-scale energy storage. However, the narrow electrochemical stability window and complex interfacial side reactions of water fundamentally limit their energy density and cycle life. In biological cells, the highly crowded intracellular environment governs vital biochemical processes by restricting water mobility. Inspired by this natural mechanism, molecular crowding electrolytes (MCEs) have been developed to manipulate the hydrogen-bonding network of aqueous electrolytes. This review provides a systematic overview of aqueous lithium-ion, sodium-ion, zinc-ion, iron-metal, aluminum-metal, and proton batteries. By introducing proper crowding agents, MCE effectively sequesters water molecules into localized coordination environments, thereby suppressing water-driven parasitic reactions without relying on extreme salt concentrations. The adoption of MCE could enable next-generation aqueous batteries with high energy density and prolonged cycling stability.
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 increased complexity by introducing high configurational entropy (S _config ), which can contribute to stabilizing single-phase solid solutions by counterbalancing enthalpic driving forces for phase separation. 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, with their vast combinatorial design space enabling the tuning of these effects across a wide range of compositions. 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.
Hybrid halide perovskites are promising absorber materials for photovoltaic applications due to their high efficiency and low-temperature solution processability. The choice of solvent is therefore critical, as it can strongly influence the crystallisation pathway and ultimately the efficiency of the solar cell. To investigate this, an in-depth study of the early stage of crystallisation of MAPbI3 from solution was performed by analysing precursor solutions with small-angle x-ray scattering (SAXS). These solutions were prepared by mixing the precursors PbI2 and MAI in different solvents as GBL, DMF, NMP, DMSO and binary mixtures. These solvents differ in Gutmann's donor number (DN) and in molecular size, which can influence the arrangement of species in the solution. Detailed analysis of the SAXS data revealed that solvents with high DN (e.g. NMP and DMSO) favour homogeneous precursor solutions i.e. all the scattering objects have the same size, whereas solvents with low DN favour the presence of species with a variety of sizes in solution. Applying the scattering objects' core-shell model, where the core is formed by [PbI6]4- octahedra surrounded by a shell of solvent molecules, the agglomerates present in the solution could be described. Solvents with high DN favour the single octahedron arrangement in the core, whereas solvents with low DN favour a mixture of objects whose core is a single or a corner-sharing octahedron. This observation agrees well with the polydispersity behaviour derived from the structural analysis of the SAXS data. These deep insights and understanding on how the nature of the solvent influences the precursor arrangement in solution lay the groundwork for designing an optimised solution-based processing of halide perovskite thin films.
The paired synthesis of formic acid/formate (FA) by cathodic reduction of CO2 and anodic oxidation of methanol was evaluated using aqueous solutions with different supporting electrolytes (SE) (Na2SO4, KHCO3, NaOH) and a Sn cathode combined with various anodic materials (Pt, Cu, Ni(OH)(2), Ni NPs, Ti/IrO2-Ta2O5, Ti/RuO2, boron-doped diamond (BDD) and Ti4O7) with the main aims to evaluate what electrolytes are required by the cathodic and anodic processes and the performances of various anodes in different electrolytes. It was found that the cathodic and anodic processes require very different electrolytes: the cathodic reduction of CO2 is strongly affected by the adopted SE, and it is favoured by working in acidic solutions. Conversely, methanol oxidation to FA at the anode is favoured by using NaOH solutions at very high pH. Hence, the best results were achieved using different electrolytes in the anodic and cathodic compartments. Ni-based anodes gave the highest faradaic efficiencies (FEFA = 94%-100%) for the FA production in 0.5 M NaOH solutions, especially at low current densities. Just slightly lower FEFA were found under these conditions at BDD anode; moreover, the BDD gave the best results in the other tested electrolytes, although FEFA was significantly lower than in NaOH solutions.
This work demonstrates novel highly tunable multiband photodetectors based on highly mismatched alloys, in particular dilute GaAsN. The device features a monolithic anti-parallel structure (Au/n-GaAs (substrate)/p-AlGaAs/n-GaAsN/p-GaAsN/p-AlGaAs/Au) with three stacked p/n junctions, engineered to exploit the unique three active energy bands structure in GaAsN. By varying the nitrogen concentration within the range of 3%-5% in the GaAsN layers, the energy band positions can be adjusted, enabling precise tuning of the photodetector's spectral response. Under bias, the different p/n junctions in the device are either connected in forward or reverse polarity simultaneously. The operational principles are based on an interband tunneling carrier transport mechanism at the reverse-biased junctions in conjunction with diffusion currents in the forward-biased junctions. We present the design, growth, and characterization of the devices, showing that their photocurrent can be selectively activated across different spectral ranges by adjusting the nitrogen composition in the GaAsN layers. As examples, device-1 (3% N) exhibits a dual-band response at 500 nm and 800 nm with an external quantum efficiency (EQE) of 2.15% at 500 nm and 0.13% at 800 nm, a specific detectivity (D*) of 1.8 & times; 1010 Jones, and response times of 370 & micro;s (rise) and 200 & micro;s (fall), while device-3 (5% N) shows a single narrow-band response at 940 nm. Importantly, the devices were not optimized for high EQE; rather, the key achievement is the tunable spectral response achieved simply by varying the nitrogen content in the GaAsN layers. This approach establishes a new paradigm for spectrally agile photodetection, moving beyond traditional filter-based or complex tandem structures to a simplified, material-centric tuning strategy.
