The inhibition of this polysulfide shuttle effect and the promotion of the redox reaction kinetics remains as the key material challenges of lithium-sulfur batteries (LSBs) to be urgently solved.Here we report a new architecture for the cathode material based on nanoreactor of ZnSe/Ndoped hollow carbon (ZnSe/NHC). This material combination and the hollow geometry provide three key benefits to the LSBs cathode: i) The combination of lithiophilic sites of NHC and sulfiphilic sites of ZnSe effectively trap LiPS as demonstrated by experimental results and density functional theory (DFT) calculations; ii) In part related to this promoted adsorption, the ZnSe/NHC material combination is able to facilitate the Li + diffusion, thus promoting the redox reaction kinetics; iii) The hollow nanoreactor design traps LiPS and accommodates volumetric expansion preventing the cathode material decomposition. As a result, LSBs cathodes based on this hybrid material, S@ZnSe/NHC, are characterized by high initial capacities, 1475 mAh g −1 at 0.1 C and 542 mAh g −1 at 3 C, and excellent rate capability. Besides, these cathodes deliver stable operation with only 0.022% capacity decay per cycle after 800 cycles at 3 C. Even at high sulfur loading of 3.2 mg cm −2 , a reversible capacity of 540.5 mAh g −1 is delivered after 600 cycles at 1 C. Overall, this work not only further demonstrates the large potential of transitionmetal selenides as cathode materials in LSBs, but also demonstrates the nanoreactor design to be a highly suitable architecture to enhance cycle stability.

The shuttle effect and sluggish conversion kinetics of lithium polysulfides (LiPS) hamper the practical application of lithium–sulfur batteries (LSBs). Toward overcoming these limitations, herein an in situ grown C2N@NbSe2 heterostructure is presented with remarkable specific surface area, as a Li–S catalyst and LiPS absorber. Density functional theory (DFT) calculations and experimental results comprehensively demonstrate that C2N@NbSe2 is characterized by a suitable electronic structure and charge rearrangement that strongly accelerates the LiPS electrocatalytic conversion. In addition, heterostructured C2N@NbSe2 strongly interacts with LiPS species, confining them at the cathode. As a result, LSBs cathodes based on C2N@NbSe2/S exhibit a high initial capacity of 1545 mAh g−1 at 0.1 C. Even more excitingly, C2N@NbSe2/S cathodes are characterized by impressive cycling stability with only 0.012% capacity decay per cycle after 2000 cycles at 3 C. Even at a sulfur loading of 5.6 mg cm−2, a high areal capacity of 5.65 mAh cm−2 is delivered. These results demonstrate that C2N@NbSe2 heterostructures can act as multifunctional polysulfide mediators to chemically adsorb LiPS, accelerate Li‐ion diffusion, chemically catalyze LiPS conversion, and lower the energy barrier for Li2S precipitation/decomposition, realizing the “adsorption‐diffusion‐conversion” of polysulfides.

Lithium–sulfur batteries (LSBs) are considered to be one of the most promising next generation energy storage systems due to their high energy density and low material cost. However, there are still some challenges for the commercialization of LSBs, such as the sluggish redox reaction kinetics and the shuttle effect of lithium polysulfides (LiPS). Here a 2D layered organic material, C2N, loaded with atomically dispersed iron as an effective sulfur host in LSBs is reported. X‐ray absorption fine spectroscopy and density functional theory calculations prove the structure of the atomically dispersed Fe/C2N catalyst. As a result, Fe/C2N‐based cathodes demonstrate significantly improved rate performance and long‐term cycling stability. Fe/C2N‐based cathodes display initial capacities up to 1540 mAh g−1 at 0.1 C and 678.7 mAh g−1 at 5 C, while retaining 496.5 mAh g−1 after 2600 cycles at 3 C with a decay rate as low as 0.013% per cycle. Even at a high sulfur loading of 3 mg cm−2, they deliver remarkable specific capacity retention of 587 mAh g−1 after 500 cycles at 1 C. This work provides a rational structural design strategy for the development of high‐performance cathodes based on atomically dispersed catalysts for LSBs.

Solution‐processed and low‐temperature Sn‐rich perovskites show their low bandgap of about 1.2 eV, enabling potential applications in next‐generation cost‐effective ultraviolet (UV)–visible (vis)–near infrared (NIR) photodetection. Particularly, the crystallization (crystallinity and orientation) and film (smooth and dense film) properties of Sn‐rich perovskites are critical for efficient photodetectors, but are limitedly studied. Here, controllable crystallization for growing high‐quality films with the improvements of increased crystallinity and strengthened preferred orientation through a introducing rubidium cation into the methylammonium Sn‐Pb perovskite system (65% Sn) is achieved. Fundamentally, the theoretical results show that rubidium incorporation causes lower surface energy of (110) plane, facilitating growth in the dominating plane and suppressing growth of other competing planes. Consequently, the methylammonium‐rubidium Sn‐Pb perovskite photodetectors simultaneously achieve larger photocurrent and lower noise current. Finally, highly efficient UV–vis–NIR (300–1100 nm) photodetectors with record‐high linear dynamic range of 110 and 3 dB cut‐off frequency reaching 1 MHz are demonstrated. This work contributes to enriching the cation selection in Sn‐Pb perovskite systems and offering a promising candidate for low‐cost UV–vis–NIR photodetection.

The shuttling behavior and sluggish conversion kinetics of the intermediate lithium polysulfides (LiPS) represent the main obstructions to the practical application of lithium–sulfur batteries (LSBs). Herein, a 1D π–d conjugated metal–organic framework (MOF), Ni‐MOF‐1D, is presented as an efficient sulfur host to overcome these limitations. Experimental results and density functional theory calculations demonstrate that Ni‐MOF‐1D is characterized by a remarkable binding strength for trapping soluble LiPS species. Ni‐MOF‐1D also acts as an effective catalyst for S reduction during the discharge process and Li2S oxidation during the charging process. In addition, the delocalization of electrons in the π–d system of Ni‐MOF‐1D provides a superior electrical conductivity to improve electron transfer. Thus, cathodes based on Ni‐MOF‐1D enable LSBs with excellent performance, for example, impressive cycling stability with over 82% capacity retention over 1000 cycles at 3 C, superior rate performance of 575 mAh g−1 at 8 C, and a high areal capacity of 6.63 mAh cm−2 under raised sulfur loading of 6.7 mg cm−2. The strategies and advantages here demonstrated can be extended to a broader range of π–d conjugated MOFs materials, which the authors believe have a high potential as sulfur hosts in LSBs.

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The electrochemical oxygen evolution reaction (OER) plays a fundamental role in several energy technologies, which performance and cost-effectiveness are in large part related to the used OER electrocatalyst. Herein, we detail the synthesis of cobalt-iron oxide nanosheets containing controlled amounts of well-anchored SO 4 2− anionic groups (CoFe x O y -SO 4 ). We use a cobalt-based zeolitic imidazolate framework (ZIF-67) as the structural template and a cobalt source and Mohr's salt ((NH 4 ) 2 Fe(SO 4 ) 2 •6H 2 O) as the source of iron and sulfate. When combining the ZIF-67 with ammonium iron sulfate, the protons produced by the ammonium ion hydrolysis (NH 4 + + H 2 O = NH 3 •H 2 O + H + ) etch the ZIF-67, dissociating its polyhedron structure, and form porous assemblies of two-dimensional nanostructures through a diffusion-controlled process. At the same time, iron ions partially replace cobalt within the structure, and SO 4 2− ions are anchored on the material surface by exchange with organic ligands. As a result, ultrathin CoFe x O y -SO 4 nanosheets are obtained. The proposed synthetic procedure enables controlling the amount of Fe and SO 4 ions and analyzing the effect of each element on the electrocatalytic activity. The optimized CoFe x O y -SO 4 material displays outstanding OER activity with a 10 mA cm −2 overpotential of 268 mV, a Tafel slope of 46.5 mV dec −1 , and excellent stability during 62 h. This excellent performance is correlated to the material's structural and chemical parameters. The assembled nanosheet structure is characterized by a large electrochemically active surface area, a high density of reaction sites, and fast electron transportation. Meanwhile, the introduction of iron increases the electrical conductivity of the catalysts and provides fast reaction sites with optimum bond energy and spin state for the adsorption of OER intermediates. The presence of sulfate ions at the catalyst surface modifies the electronic energy level of active sites, regulates the adsorption of intermediates to reduce the OER overpotential, and promotes the surface charge transfer, which accelerates the formation of oxygenated intermediates. Overall, the present work details the synthesis of a high-efficiency OER electrocatalyst and demonstrates the introduction of nonmetallic anionic groups as an excellent strategy to promote electrocatalytic activity in energy conversion technologies.

Atomically dispersed metals maximize the number of catalytic sites and enhance their activity. However, their challenging synthesis and characterization strongly complicates their optimization. Here, the aim is to demonstrate that tuning the electronic environment of atomically dispersed metal catalysts through the modification of their edge coordination is an effective strategy to maximize their performance. This article focuses on optimizing nickel-based electrocatalysts toward alcohol electrooxidation in alkaline solution. A new organic framework with atomically dispersed nickel is first developed. The coordination environment of nickel within this framework is modified through the addition of carbonyl (CO) groups. The authors then demonstrate that such nickel-based organic frameworks, combined with carbon nanotubes, exhibit outstanding catalytic activity and durability toward the oxidation of methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), and benzyl alcohol (C 6 H 5 CH 2 OH); the smaller molecule exhibits higher catalytic performance. These outstanding electrocatalytic activities for alcohol electrooxidation are attributed to the presence of the carbonyl group in the ligand chemical environment, which enhances the adsorption for alcohol, as revealed by density functional theory calculations. The work not only introduces a new atomically dispersed Ni-based catalyst, but also demonstrates a new strategy for designing and engineering high-performance catalysts through the tuning of their chemical environment.