All-solid-state Li-ion batteries (ASSBs) represent a promising leap forward in battery technology, rapidly advancing in development. Among the various solid electrolytes, argyrodite thiophosphates Li6PS5X (X=Cl, Br, I) stand out due to their high ionic conductivity, structural flexibility, and compatibility with a range of electrode materials, making them ideal candidates for efficient and scalable battery applications. However, despite significant performance advancements, the sustainability and recycling of ASSBs remain underexplored, posing a critical challenge for achieving efficient circular processes. This study investigates the dissolution-based separation and recovery of argyrodite thiophosphate electrolytes and transition metal oxide electrode materials as a potential recycling strategy for ASSBs. A focus is set on the impact of solvent treatments on the recrystallization behavior of these electrolytes. Furthermore, the interactions between dissolved argyrodite thiophosphates and various transition metal oxide electrode materials (LiCoO2, LiMn2O4, LiNi0.8Mn0.1Co0.1O2, LiFePO4 and Li4Ti5O12) is examined to assess their influence on the functional properties of both the electrolytes and electrode materials. Structural, compositional and morphological changes are analyzed using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry and X-ray photoelectron spectroscopy. Our findings provide insights into the complexities of recycling ASSBs, but also highlight the potential for developing efficient, sustainable recycling processes.

AbstractThe discovery of 80 K superconductivity in bilayer La3Ni2O7 at pressures greater than 14 GPa presents a unique opportunity to study a novel class of high-temperature superconductors. Therefore, other bilayer nickelates following the classical (T4+) Ruddlesden-Popper (RP) series of Sr3Ni2O7 would present an interesting new candidate. In this work, we study the stabilization of RP n = 2 phase in Sr3Ni2−xAlxO7−δ, via floating zone growth of crystals. With powder and single-crystal XRD, we study the stability range of the RP-type phase. Our Thermogravimetric Analysis (TGA), X-ray photoelectron spectroscopy (XPS) and gas extraction studies reveal a remarkably high oxidation state of Ni4+ stabilized by chemical strain from Al. The obtained black crystals are insulating in transport and show a magnetic transition around 12 K.

The direct coupling of light harvesting and charge storage in a single material opens new avenues to light storing devices. Here we demonstrate the decoupling of light and dark reactions in the two-dimensional layered niobium tungstate (TBA)+(NbWO6)- for on-demand hydrogen evolution and solar battery energy storage. Light illumination drives Li+/H+ photointercalation into the (TBA)+(NbWO6)- photoanode, leading to small polaron formation assisted by structural distortions on the WOx sublattice, along with a light-induced decrease in material resistance over 2 orders of magnitude compared to the dark. The photogenerated electrons can be extracted on demand to produce solar hydrogen upon the addition of a Pt catalyst. Alternatively, they can be stored for over 20 h under oxygen-free conditions after 365 nm UV illumination for only 10 min, thus featuring a solar battery anode with promising capacity and long-term stability. The optoionic effects described herein offer new insights to overcome the intermittency of solar irradiation, while inspiring applications at the interface of solar energy conversion and energy storage, including solar batteries, "dark" photocatalysis, solar battolyzers, and photomemory devices.

The existence of superconductivity (SC) appears to be established in both twisted and nontwisted graphene multilayers. However, whether their building block, single-layer graphene (SLG), can also host SC remains an open question. Earlier theoretical works predicted that SLG could become a chiral d-wave superconductor driven by electronic interactions when doped to its van Hove singularity, but questions such as whether the d-wave SC survives the strong band renormalizations seen in experiments, its robustness against the source of doping, or if it will occur at any reasonable critical temperature (T c) have remained difficult to answer, in part due to uncertainties in model parameters. Furthermore, doping of graphene beyond its van Hove singularity remained experimentally challenging and was not demonstrated until recently. In this study, we n dope SLG past the van Hove singularity by employing Tb intercalation and derive structural models from angle-resolved photoemission spectroscopy measurements. We adopt a reliable numerical framework based on a random-phase approximation technique to investigate the emergence of unconventional SC in the heavily doped monolayer. We predict that robust d + id topological SC could arise in SLG doped by Tb, with a T c up to 600 mK. We also employ first-principles calculations to investigate the possibility of realizing d-wave SC with other dopants, such as Li or Cs. We find that dopants that change the lattice symmetry of SLG are detrimental to the d-wave state. The stability of the d-wave SC predicted here in Tb-doped SLG could provide a valuable insight for guiding future experimental efforts aimed at exploring topological superconductivity in monolayer graphene.

All-solid-state batteries are currently developed at high pace and show a strong potential for market introduction within the next years. Though their performance has improved considerably over the last years, investigation of their sustainability and the development of suitable recycling strategies have received less attention. However, their potential for efficient circular processes must be accessed comprehensively. In this article, we investigate the separation of the solid electrolyte beta-Li3PS4 from different lithium transition metal oxide electrode materials (LiCoO2, LiMn2O4, LiNi0.8Mn0.1Co0.1O2, LiFePO4, LiNi0.85Co0.1Al0.05O2 and Li4Ti5O12) via an approach based on the dissolution and subsequent recrystallization of the thiophosphate using N-methylformamide as solvent. A combination of X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-mass spectrometry, iodometric titration and X-ray photoelectron spectroscopy as well as electrochemical impedance spectroscopy and electrochemical characterization was used to characterize the electrolyte and electrode materials before and after separation. We find that the presence of electrode materials in the dissolution process can lead to significant chemical reactions. These interactions can (but most not) lead to strong alteration of the electrochemical characteristics of the individual compounds. Thus, we show that an efficient recovery of materials will likely depend on the precise material combination within an all-solid-state battery.

Two-dimensional (2D) van der Waals (vdW) materials offer rich tuning opportunities generated by different stacking configurations or by introducing intercalants into the vdW gaps. Current knowledge of the interplay between stacking polytypes and intercalation often relies on macroscopically averaged probes, which fail to pinpoint the exact atomic position and chemical state of the intercalants in real space. Here, by using atomic-resolution electron energy-loss spectroscopy in a scanning transmission electron microscope, we visualize a stacking-selective self-intercalation phenomenon in thin films of the transition-metal dichalcogenide (TMDC) Nb1+xSe2. We observe robust contrasts between 180°-stacked layers with large amounts of Nb intercalants inside their vdW gaps and 0°-stacked layers with little detectable intercalants inside their vdW gaps, coexisting on the atomic scale. First-principles calculations suggest that the films lie at the boundary of a phase transition from 0° to 180° stacking when the intercalant concentration x exceeds ~0.25, which we could attain in our films due to specific kinetic pathways. Our results offer not only renewed mechanistic insights into stacking and intercalation, but also open up prospects for engineering the functionality of TMDCs via stacking-selective self-intercalation.

The synthesis of new graphene-based quantum materials by intercalation is an auspicious approach. However, an accompanying proximity coupling depends crucially on the structural details of the new heterostructure. It is studied in detail the Pb monolayer structure after intercalation into the graphene buffer layer on the SiC(0001) interface by means of photoelectron spectroscopy, x-ray standing waves, and scanning tunneling microscopy. A coherent fraction close to unity proves the formation of a flat Pb monolayer on the SiC surface. An interlayer distance of 3.67 & ANGS; to the suspended graphene underlines the formation of a truly van der Waals heterostructure. The 2D Pb layer reveals a quasi ten-fold periodicity due to the formation of a grain boundary network, ensuring the saturation of the Si surface bonds. Moreover, the densely-packed Pb layer also efficiently minimizes the doping influence by the SiC substrate, both from the surface dangling bonds and the SiC surface polarization, giving rise to charge-neutral monolayer graphene. The observation of a long-ranged (3x3$\sqrt {3}\times \sqrt {3}$) reconstruction on the graphene lattice at tunneling conditions close to Fermi energy is most likely a result of a nesting condition to be perfectly fulfilled.

A series of Li 3 MI 6 compounds with M = Lu–Sm were produced by ball milling and solid state synthesis. Cation disorder within the layers largely influences the ionic transport properties, which can be tuned by isovalent and aliovalent substitution.

We studied chemical stability of atomic layer deposition-grown Al2O3 artificial solid electrolyte interphases (SEIs) on lithium and sodium upon contact with liquid electrolyte by electrochemical impedance spectroscopy (EIS) and in the case of Li also by x-ray photoelectron spectroscopy. Both methods show that the formed Al2O3 is porous for all nominal thicknesses, and that the natural SEI grows in its pores and cracks. EIS shows that the porosity of the SEI on Na is higher than the one observed on Li, in particular at higher nominal thicknesses of Al2O3. The observed values of activation energies related to the transport through the SEI indicate either a denser natural SEI in the pores of Al2O3 and/or considerable space charge effect between Al2O3 and the SEI phase.

Engineering of the interface between perovskite absorber thin films and charge transport layers has fueled the development of perovskite solar cells (PSCs) over the past decade. For p‐i‐n PSCs, the development and adoption of hole transport layers utilizing self‐assembled monolayers (SAM‐HTLs) based on carbazole functional groups with phosphonic acid anchoring groups has enabled almost lossless contacts, minimizing interfacial recombination to advance power conversion efficiency in single‐junction and tandem solar cells. However, so far these materials have been deposited exclusively via solution‐based methods. Here, for the first time, vacuum‐based evaporation of the most common carbazole‐based SAM‐HTLs (2PACz, MeO‐2PACz, and Me‐4PACz) is reported. X‐ray photoelectron spectroscopy and infrared spectroscopy demonstrate no observable chemical differences in the evaporated SAMs compared to solution‐processed counterparts. Consequently, the near lossless interfacial properties are either preserved or even slightly improved as demonstrated via photoluminescence measurements and an enhancement in open‐circuit voltage. Strikingly, applying evaporated SAM‐HTLs to complete PSCs demonstrates comparable performance to their solution‐processed counterparts. Furthermore, vacuum deposition is found to improve perovskite wetting and fabrication yield on previously non‐ideal materials (namely Me‐4PACz) and to display conformal and high‐quality coating of micrometer‐sized textured surfaces, improving the versatility of these materials without sacrificing their beneficial properties.

Realization of all-solid-state batteries combined with metallic Li/Na is still hindered due to the unstable interface between the alkali metal and solid electrolytes, especially for highly promising thiophosphate materials. Artificial and uniform solid-electrolyte interphases (SEIs), serving as thin ion-conducting films, have been considered as a strategy to overcome the issues of such reactive interfaces. Here, we synthesized sulfide-based artificial SEIs (LixSy and NaxSy) on Li and Na by solid/gas reaction between the alkali metal and S vapor. The synthesized films are carefully characterized with various chemical/electrochemical techniques. We show that these artificial SEIs are not beneficial from an application point of view since they either contribute to additional resistances (Li) or do not prevent reactions at the alkali metal/electrolyte interface (Na). We show that NaxSy is more porous than LixSy, supported by (i) its rough morphology observed by focused ion beam-scanning electron microscopy, (ii) the rapid decrease of Rinterface (interfacial resistance) in NaxSy-covered-Na symmetric cells with liquid electrolyte upon aging under open-circuit potential, and (iii) the increase of Rinterface in NaxSy-covered-Na solid-state symmetric cells with Na3PS4 electrolyte. The porous SEI allows the penetration of liquid electrolyte or alkali metal creep through its pores, resulting in a continuous chemical reaction. Hence, porosity of SEIs in general should be carefully taken into account in the application of batteries containing both liquid electrolyte and solid electrolyte.

Polymer-based electrolytes can greatly promote the development of rechargeable metal-sulfur batteries owing to the improved safety and high flexibility; however, liquid electrolytes, which are mostly investigated so far, often hinder practical application due to the severe shuttling effect and possible leakage of the electrolytes. Herein, a new cell design is presented, that bridges the gap between lab cells and application by a novel halogen-free gel-polymer-electrolyte (GPE) with outstanding electrochemical performance. The GPE was prepared via an in-situ crosslinking reaction between lithium/magnesium borohydrides and poly(tetrahydrofuran). This GPE displays outstanding ionic conductivities in a wide temperature range, superior polarization behavior, remarkable reversibility and more strikingly, excellent compatibility with different sulfur containing and intercalation cathodes: S8@activated carbon cloth (ACC/S), sulfur poly(acrylonitrile) (SPAN) composite, titanium disulfide, Chevrel phase Mo6S8 and lithium titanate. The effective suppression of the 'polysulfide shuttle' by the GPE allows for a stable cycling of Mg||SPAN and Mg||ACC/S cells at room temperature with high discharge capacities (600 and 420 mAh.gs(-1) after 140 and 50 cycles, respectively). Remarkably, the Mg||GPE||SPAN system features low self-discharge, excellent flexibility and safety characteristics, which significantly improve the possibility for practical applications.

Among 'beyond lithium ion' energy storage, lithium sulfur (Li-S) batteries are one of the most promising technologies, as a result of the potential for high theoretical energy capacity at low cost. A key obstacle in exploiting the vast potential of Li-S batteries is the formation of soluble polysulfide species. Here, we report sulfurized polypropylene (S/PP-500) synthesized in one-step by reacting polypropylene (PP) with sulfur as a new polysulfide shuttle-free cathode material for Li-S batteries. It exhibits a reversible capacity as high as 1000 mAh/gsulfur at 0.1 C and a sulfur loading of up to 68 wt%, which in turn allows for high sulfur loadings up to 47 % in the final cathode. The low-cost starting materials together with the simple synthetic procedure and the good electrochemical performance in combination with a commercially available eslectrolyte make the S/PP-500 a very promising cathode material for Li-S batteries.

2D metal–organic-framework (MOF) based composites have emerged as promising candidates for electrocatalysis due to their high structural flexibility and fully exposed active sites. Herein, a freestanding metal–organic layer (MOL) with a 2D kgd (kagome dual) lattice was constructed with abundant surface oxygenate groups serving as anchoring sites to immobilize diverse guests. Taking Bi as an example, tetragonal Bi 2 O 3 nanowires can be uniformly grown on MOLs after solvothermal treatment, the structural evolution of which was followed by ex situ electron microscopy. The as-prepared Bi 2 O 3 /MOL exhibits excellent CO 2 electroreduction activity towards formate reaching a specific current of 2.3 A mg Bi −1 and Faradaic efficiencies of over 85 % with a wide potential range from −0.87 to −1.17 V, far surpassing Bi 2 O 3 /UiO (a 3D Zr 6 -oxo based MOF) and Bi 2 O 3 /AB (Acetylene Black). Such a post-synthetic modification strategy can be flexibly extended to develop versatile MOL composites, highlighting the superiority of optimizing MOL-based composites for electrocatalysis.

Lithium-sulfur (Li-S) batteries are among the most promising candidates for next-generation high-energy-density batteries; however, the polysulfide shuttle represents a major drawback in their application. Here, we report on sulfurized poly(norbornadiene) (S/pNBD) and its analogue, sulfurized poly(dicyclopentadiene) (S/pDCPD), two polysulfide shuttle-free and cheap cathode materials with good performance in Li-S battery technology. Both S/pNBD and S/pDCPD can be prepared in a straightforward two-step procedure. Time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy measurements, and cyclic voltammetry indicate that all sulfur in S/pNBD and S/pDCPD is covalently bound to the polymer matrix in the form of C-Sx-C units. Li-S cells based on an S/pNBD cathode exhibit a high discharge capacity up to 1050 mA h/g sulfur at 1 C with a good capacity retention of 62 % after 1900 cycles. The structurally similar analogue S/pDCPD shows comparable electrochemical performance, again with excellent capacity retention. The high reversibility and ultra-long cycle life of both, S/pNBD and S/pDCPD, are attributed to the covalent binding of sulfur to the polymer backbone.

Intercalation is an established technique for tailoring the electronic structure of epitaxial graphene. Moreover, it enables the synthesis of otherwise unstable two-dimensional (2D) layers of elements with unique physical properties compared to their bulk versions due to interfacial quantum confinement. In this work, we present uniformly Pb-intercalated quasifreestanding monolayer graphene on SiC, which turns out to be essentially charge neutral with an unprecedented p-type carrier density of only (5.5±2.5)×10^{9} cm^{−2}. Probing the low-energy electronic structure throughout the entire first surface Brillouin zone by means of momentum microscopy, we clearly discern additional bands related to metallic 2D Pb at the interface. Low-energy electron diffraction further reveals a 10×10 Moiré superperiodicity relative to graphene, counterparts of which cannot be directly identified in the available band structure data. Our experiments demonstrate 2D interlayer confinement and associated band structure formation of a heavy-element superconductor, paving the way towards strong spin-orbit coupling effects or even 2D superconductivity at the graphene-SiC interface.

Mohamed Oudah1,2,∗ Minu Kim, Ksenia S. Rabinovich, Kateryna Foyevtsova, Graham McNally, Berkay Kilic, Kathrin Küster, Robert Green, Alexander V. Boris, George Sawatzky, Andreas P. Schnyder, D. A. Bonn, Bernhard Keimer, and Hidenori Takagi Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada Department of Physics & Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada Department of Physics, University of Tokyo, Bunkyo-ku, Hongo 7-3-1, Tokyo 113-0033, Japan (Dated: June 18, 2021)

2D materials such as graphene, hexagonal boron nitride ( h‐ BN), or transition metal dichalcogenides, and their heterostacks are gaining increasing interest because of their extraordinary properties, which can range from superconductivity to large charge carrier mobilities. In this paper, the electronic and structural modifications of h‐ BN on Rh(111) are investigated by the intercalation of carbon forming graphene nanoflakes between the h‐ BN and the Rh(111) surface. The carbon atoms—natural impurities in Rh bulk crystals—diffuse to the surface during the h‐ BN growth and segregate there during cooling. The graphene nanoflakes are present at particular sites under the wires of the h‐ BN nanomesh leading to an altered appearance of the Moiré pattern and modified electronic and chemical properties. Thus, a novel fabrication route of graphene nanoflakes located in a heterostack between Rh(111) and h‐ BN is shown by steering the segregation of carbon impurities at the rhodium surface.

Research on magnesium-sulfur (Mg-S) batteries has gained great attention due to the high theoretical gravimetric and volumetric energy densities (1700 Wh kg(-1) and 3200 Wh L-1), as well as because of their economic, ecologic and safety advantages. In this study, we present room-temperature Mg-S batteries with a sulfurized poly (acrylonitrile) composite (SPAN) cathode and a Mg2+/Li+ hybrid electrolyte (magnesium trifluoromethanesulfonate, (CF3SO3)(2)Mg), lithium trifluoromethanesulfonate, MgCl2 and AlCl3 in 1,2-dimethoxyethane (DME)). These cells deliver high discharge capacities and energy densities of 1100 mAh gs(-1) and 700 Wh kgs(-1) at 1 C, respectively, with >99.9% Coulombic efficiency. Electrochemical and kinetic measurements as well as post-mortem analysis revealed that utilization of SPAN and a lithium salt in the electrolyte is crucial and beneficial for the prevention of the polysulfide shuttle. It also dramatically reduces the cell resistance and the overpotential via the formation of MgLiSx species. Concomitantly, this system supports the formation of a solid electrolyte interface (SEI) layer, which greatly improves the reaction kinetics of the Mg2+ ions and the cycle performance.

Carbon nitrides constitute a class of earth‐abundant polymeric semiconductors, which have high potential for tunability on a molecular level, despite their high chemical and thermal inertness. Here the first postsynthetic modification of the 2D carbon nitride poly(heptazine imide) (PHI) is reported, which is decorated with terminal melamine (Mel) moieties by a functional group interconversion. The covalent attachment of this group is verified based with a suite of spectroscopic and microscopic techniques supported by quantum–chemical calculations. Using triethanolamine as a sacrificial electron donor, Mel‐PHI outperforms most other carbon nitrides in terms of hydrogen evolution rate (5570 µmol h −1 g −1 ), while maintaining the intrinsic light storing properties of PHI. The origin of the observed superior photocatalytic performance is traced back to a modified surface electronic structure and enhanced interfacial interactions with the amphiphile triethanolamine, which imparts improved colloidal stability to the catalyst particles especially in contrast to methanol used as donor. However, this high activity can be limited by oxidation products of donor reversibly building up at the surface, thus blocking active centers. The findings lay out the importance of surface functionalization to engineer the catalyst–solution interface, an underappreciated tuning parameter in photocatalytic reaction design.