Despite large theoretical energy densities, metal-sulfide electrodes for energy storage systems face several limitations that impact the practical realization. Here, we present the solution-processable, room temperature (RT) synthesis, local structures, and application of a sulfur-rich Mo3S13 chalcogel as a conversion-based electrode for lithium-sulfide batteries (LiSBs). The structure of the amorphous Mo3S13 chalcogel is derived through operando Raman spectroscopy, synchrotron X-ray pair distribution function (PDF), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) analysis, along with ab initio molecular dynamics (AIMD) simulations. A key feature of the three-dimensional (3D) network is the connection of Mo3S13 units through S-S bonds. Li/Mo3S13 half-cells deliver initial capacity of 1013 mAh g-1 during the first discharge. After the activation cycles, the capacity stabilizes and maintains 312 mAh g-1 at a C/3 rate after 140 cycles, demonstrating sustained performance over subsequent cycling. Such high-capacity and stability are attributed to the high density of (poly)sulfide bonds and the stable Mo-S coordination in Mo3S13 chalcogel. These findings showcase the potential of Mo3S13 chalcogels as metal-sulfide electrode materials for LiSBs.

Chalcogenide-based (aero)gel, also known as chalcogel, represents a distinct category of porous, nanoaggregated materials characterized by their highly disordered and amorphous structure. The predominant structural feature within chalcogel nanoparticles is the presence of a polysulfide backbone, which can mimic a sulfur equivalent electrode material for Li-ion sulfide batteries. This work endeavors to expand explore chalcogel’s applications in developing high-energy-density materials as conversion-based sulfur equivalents electrodes for lithium-ion batteries. We have also pioneered the synthesis of a novel class of materials called "chalcocarbogels," which have demonstrated exceptional specific capacity and cyclic stability in both Li-ion and Na-ion batteries. Our work underscores the promising prospects of chalcogenide-based aerogels in advancing energy storage technologies and addressing environmental challenges.

Perovskite solar cells (PSCs) consisting of interfacial two- and three-dimensional heterostructures that incorporate ammonium ligand intercalation have enabled rapid progress toward the goal of uniting performance with stability. However, as the field continues to seek ever-higher durability, additional tools that avoid progressive ligand intercalation are needed to minimize degradation at high temperatures. We used ammonium ligands that are nonreactive with the bulk of perovskites and investigated a library that varies ligand molecular structure systematically. We found that fluorinated aniliniums offer interfacial passivation and simultaneously minimize reactivity with perovskites. Using this approach, we report a certified quasi-steady-state power-conversion efficiency of 24.09% for inverted-structure PSCs. In an encapsulated device operating at 85°C and 50% relative humidity, we document a 1560-hour T85 at maximum power point under 1-sun illumination.

The low capacities of commercial Li ion batteries and cycle instabilities of amorphous metal sulfide based batteries impose constraints on their utilization for large-scale energy storage. We report here the acid-free, room-temperature (RT), and solution-based synthesis of a chalcogenide-carbonaceous hybrid aerogel, termed as "chalcocarbogel", comprising molybdenum sulfide (MoSx) and graphene oxide (GO). The chalcocarbogel is a nanoparticle-aggregated, porous, amorphous gel consisting of Mo3S13 and Mo2S12-like structures as determined by synchrotron X-ray PDF, XANES, and EXAFS. The MoSx-GO chalcocarbogel demonstrates high specific capacities of similar to 1215 and similar to 807 mAh g(-1) for Li/MoSx-GO and Na/MoSx-GO cells, respectively, for a 50 mAg(-1) discharge rate during the first cycle. After the activation cycles, the MoSx-GO chalcocarbogel stabilizes, maintaining high specific capacities of approximately similar to 700 mAh g(-1) for Li/MoSx-GO and similar to 473 mAh g(-1) for Na/MoSx-GO cells, while continuously cycling. The MoSx-GO aerogel reported here serves as a promising platform to develop chalcocarbogels for applications spanning both Li and Na ion batteries.

Although renewable energy sources like solar and windprovide alternativesto fossil fuels for electricity generation, liquid transportationfuels are still required for marine and aviation travel, the electrificationof which remains years or decades away. For these applications, biofuelsproduced through the deoxygenation of biomass provide a viable alternative.To elucidate the mechanism behind the deoxygenation of oleaginousbiomass to hydrocarbons via decarbonylation (DCN), this work presentsa joint experimental and computational investigation wherein propanoicacid (PAc) and a Ni[111] surface were used to model fatty acids andNi-based catalysts. Diffuse reflectance infrared Fourier transformspectroscopy (DRIFTS) measurements show the binding mode of PAc onNi/Al2O3 to be predominantly bidentate, whichinformed density functional theory (DFT) studies. The bidentate adsorptionmode of PAc plays a key role in determining the DCN mechanism since & alpha;-carbon dehydrogenation of PAc was deemed unfeasible, in contrastwith previous reports. A mean-field microkinetic model reveals thefollowing dominant pathway at 573 K: PAc dehydroxylation affords aCH(3)CH(2)CO* intermediate that after two & alpha;-carbondehydrogenation steps forms CH3CCO*, which then undergoesCO abstraction and hydrogenation to ultimately yield ethane. The overallreaction has a turnover frequency (TOF) of 2.75 x 10(-11) s(-1), with the dehydroxylation of CH3CH2COOH* being the rate-determining step with a degreeof rate control of one. The apparent activation barrier determinedhere is much lower than that previously reported, which could be dueto the binding mode of PAc and considered experimental conditions.The effect of partial pressures of gaseous intermediates on the overallrate of reaction showed a negative order with respect to H-2 partial pressure, while a positive order was observed with respectto PAc partial pressure. Overall, this work shows the importance ofexperimentally determining the binding mode of carboxylic acids onthe catalyst surface to inform DFT work designed to elucidate theDCN reaction mechanisms.

We report the design, synthesis, and characterization of four N-annulated perylene diimide (NPDI) functionalized rhenium bipyridine [Re(bpy)] supramolecular dyads. The Re(bpy) scaffold was connected to the NPDI chromophore either directly [Re(py-C0-NPDI)] or via an ethyl [Re(bpy-C2-NPDI)], butyl [Re(bpy-C4-NPDI)], or hexyl [Re(bpy-C6-NPDI)] alkyl-chain spacer. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-C2/4/6-NPDI) all exhibited significant current enhancement effects, while Re(py-C0-NPDI) did not. During controlled potential electrolysis (CPE) experiments at Eappl = -1.8 V vs Fc+/0, Re(bpy-C2/4/6-NPDI) all achieved comparable activity (TONco ∼ 25) and Faradaic efficiency (FEco ∼ 94%). Under identical CPE conditions, the standard catalyst Re(dmbpy) was inactive for electrocatalytic CO2 reduction; only at Eappl = -2.1 V vs Fc+/0 could Re(dmbpy) achieve the same catalytic performance, representing a 300 mV lowering in overpotential for Re(bpy-C2/4/6-NPDI). At higher overpotentials, Re(bpy-C4/6-NPDI) both outperformed Re(bpy-C2-NPDI), indicating the possibility of coinciding electrocatalytic CO2 reduction mechanisms that are dictated by tether-length and overpotential. Using UV-vis-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the NPDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory studies probing the optimized geometries and frontier molecular orbitals of various catalytic intermediates revealed that the geometric configuration of NPDI relative to the Re(bpy)-moiety plays a critical role in accessing electrons from the electron-reservoir. The improved performance of Re(bpy-C2/4/6-NPDI)dyads at lower overpotentials, relative to Re(dmbpy), highlights the utility of chromophore electron-reservoirs as a method for lowering the overpotential for CO2 conversion.

The alcohol and water-based processing of a perylene diimide (PDI) organic semiconductor into large area and solvent resistant films is reported.

Here we report on a molecular catalyst with a built-in electron-reservoir for enhanced CO2 conversion. The synthesis and characterization of this N-annulated perylene diimide (PDI) photosensitized Re(bpy) supramolecular dyad [Re(bpy-TAz-PDI)], as well as successful electro- and photocatalytic CO2-to-CO conversion, are detailed herein. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-TAz-PDI) exhibited significant current enhancement, where the onset of electrocatalytic CO2 reduction for Re(bpy-TAz-PDI) occurred at a much less negative potential than standard Re(bpy) complexes. At an applied potential of -1.8 V vs. Fc+/0, 400 mV lower than the benchmark Re(dmbpy) catalyst, Re(bpy-TAz-PDI) was able to achieve the same catalytic activity (TONco = 24) and Faradaic efficiency (FE = 92 %) during controlled potential electrolysis (CPE) experiments. Through a combination of UV-visible-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the PDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory (DFT) studies probing the optimized geometries, frontier molecular orbitals, and spin-densities of various catalytic intermediates revealed that the geometric configuration of PDI, relative to the Re(bpy)-moiety, plays a critical role in accessing electrons from the electron-reservoir. The near identical performance of Re(bpy-TAz-PDI) at lower overpotentials relative to the benchmark Re(dmbpy) catalyst highlights the utility of organic chromophore electron-reservoirs as a method for lowering the required overpotential for CO2 conversion.