Latest ArticlesZero-dimensional (0D) hybrid copper halides have attracted significant attention owing to their unique photophysical properties and remarkable structural diversity. In this work, two 0D self-assemblies compounds of copper iodide dimers were synthesized, namely, (4-MBTP)2(Cu2I4)0.5I (1) and (4-MBTP)(Cu2I4)0.5 (2) (4-MBTP = (4-methylbenzyl)triphenylphosphonium chloride). Compound 1 exhibits blue emission centered at 474 nm, while compound 2 shows yellow emission centered at 559 nm at room temperature. The results combined with crystal structure, spectroscopy analysis, characterization, and theoretical studies reveal that the blue light of compound 1 stems from multiple defect states caused by the presence of I vacancies, while the yellow emission of compound 2 is attributed to through-space charge-transfer (TSCT) and cluster-centered (CC) excited state. Strikingly, the crystal structure can transform from compound 1 into compound 2 with luminescence color change from blue to yellow through treating with methanol. This work provides a structural transformation strategy of hybrid copper halides, as well as realizes the regulation of light emission from defect states to non-defect states, making them feasible candidates for information encryption and optical data storage.
Rechargeable aqueous zinc-ion batteries (RAZIBs) have been considered as viable alternatives to lithium-ion batteries in electrochemical energy storage due to their intrinsic safety, low cost, and environmental friendliness. However, the further practical application of RAZIBs is restricted by the growth of zinc dendrites and severe side reactions during cycling. To address these issues, we proposed a new lysine (Lys) additive to the ZnSO4 electrolyte, the hydrolyzed Lys+ cations can be adsorbed on the Zn anode's surface to modify the interface between the zinc electrode and the ZnSO4 electrolyte. This modification helps weaken the "tip effect" and guides the uniform zinc deposition, effectively alleviating the formation of zinc dendrites. Additionally, introducing alkaline Lys can regulate the pH value of the ZnSO4 electrolyte and suppress side reactions, thereby decreasing the production of by-products. Consequently, the Zn||Zn symmetric cell with Lys additive stably cycled for 4500 h at 1 mA/cm2, and the Zn||NH4V4O10 full cell with Lys additive exhibited improved performance (with a capacity retention of 72% after 1000 cycles) at 5 A/g. This strategy provides valuable insights for developing stable Zn anode toward high-performance RAZIBs.
In the context of the continuously increasing energy demand, the ongoing advancement of innovative energy storage technologies is regarded as an important strategy to alleviate the energy crisis. Among various energy storage technologies, supercapacitors (SCs) demonstrate significant potential in the future energy storage sector due to their exceptional high-power density and long cycle life. As the core component of SCs, the choice of electrode materials is crucial to their performance, with carbon materials being favored for their excellent electrical conductivity and large specific surface area. In particular, porous carbon materials derived from biomass-based polymers have become a research hotspot due to their unique advantages. Through chemical modification and high-temperature carbonization, these materials can form more stable and optimized porous structures, significantly enhancing their electrochemical performance while meeting environmental protection requirements, thereby highlighting their superiority as electrode materials. This article aims to review the sources, production, and applications of carbon materials derived from biomass-based polymers. We have deeply summarized the preparation and activation methods of carbon from different biomass-based polymer sources. In addition, a comprehensive analysis and systematic comparison of novel modification techniques, such as heteroatom doping, copolymerization, and the incorporation of nanomaterials, were performed to enhance the performance of SCs. Finally, according to the technical challenges to be solved, the goal of large-scale development of biomass-based polymer-derived porous carbon in the field of energy storage is proposed, which is crucial for coping with the global energy crisis and reducing environmental impact.
The dissolution of lithium polysulfides (Li2Sx, 4 ≤ x ≤ 8, LiPSs) intermediates and slow redox kinetics are the main factors leading to the rapid capacity degradation of lithium-sulfur batteries (LSBs), significantly limits the practical development of LSBs. To overcome challenges, NbN embedded in nitrogen-doped carbon nanotubes (NbN@NCNT) composites were synthesized here as sulfur hosts by taking advantage of the superior electrical conductivity and excellent catalytic activity of the metal nitride NbN. The incorporation of NbN enhanced the polysulfides conversion efficiency and suppressed the shuttling effect, thereby enhancing cycling stability in LSBs. XPS results revealed the formation of Li2S, indicating that Li2S8 was sufficiently effectively reduced and catalytically converted to the Li2S. Consequently, after 100 cycles, the capacity retention rate of LSBs using the S/NbN@NCNT electrode reached 71.5% at a current density of 2 mA/cm2 with a high sulfur loading of 3 mg/cm2. More importantly, even at high current density of 8 mA/cm2, the battery assembled with NbN@NCNT was still able to reach the high capacity of 878.14 mAh/g, demonstrating outstanding rate capability. This study offered novel insights into the potential for enhancing the sulfur reaction kinetics in LSBs.
Semiconducting metal oxide based gas sensors exhibit great promise for convenient detection of acetone, a biomarker gas in the exhaled breath of type-Ⅰ diabetes patients. However, the detection usually suffers the interference from exhaled moisture. To overcome this challenge, in this work, a novel hierarchical heterojunction structure consisting of SnO2 nanofiber core and Co3O4 nanosheet shell (denoted as SnO2@Co3O4 core-shell composite) was proposed for fabricating acetone sensor with excellent humidity resistance. Compared with SnO2 nanofibers and Co3O4 nanosheets, the SnO2@Co3O4 showed the highest sensing response, with a response value (Rg/Ra) of 11.27-50 ppm acetone at 110 ℃. In addition, the hierarchical SnO2@Co3O4 core-shell structure shows fast response/recovery speed (19/43 s), lower detection limit (125 ppb), excellent selectivity and stability in a humidity environment (relative humidity 30%-90%) with a relative change of only 3%. The enhanced gas sensing performance toward acetone is attributed to the synergistic effect between the two components, the unique core-shell hierarchical structure and the rich oxygen vacancy density. Density functional theory calculations reveal that the SnO2@Co3O4 has higher acetone adsorption energy than the two components. In addition, a novel SnO2@Co3O4 gas sensing module and smart portable sensor device enable efficient real-time monitoring of acetone concentrations on a smartphone via Bluetooth communication.
Metal-organic framework [Zn2(tz)2(ox)] (CALF-20) has attracted great attention due to its excellent ability to capture carbon dioxide. There are great interests to develop similar adsorbents for gas adsorption and separation. To develop more efficient porous adsorbent, it is essential to study the relationship between these structures and properties. Neutron diffraction has been proved to be an excellent tool for determining both the structural details of MOF host and the precise locations of adsorbed gas within the pore, offering unique opportunities for understanding the structure-properties relationship. Herein, we report the synthesis and structure characterization of MOF [Zn2(mtz)2(ox)], which exhibits high CO2 adsorption capacity. Neutron powder diffraction experiment on the solvated, the activated and CO2 loaded samples unveils the preferred binding sites of CO2 within the MOFs, where CO2 locates toward the center of the pore and interacts with methyl group or triazole via CH···O hydrogen bonding. The adsorption process of CO2 in [Zn2(mtz)2(ox)] is accompanied by the cell volume expansion, so [Zn2(mtz)2(ox)] with more compact structure can show a better adsorption performance. The structure-properties relationship in [Zn2(mtz)2(ox)] elucidated by present study offer a path to develop more advanced porous physisorbent materials.
The replacement of Pt/C catalysts with Pt-based alloy catalysts was considered a promising strategy to reduce platinum-group-metal (PGM) content in proton exchange membrane fuel cell. However, inexpensive transition metal atoms in Pt-based alloy catalysts are subject to metal dissolution issues, leading to stability issues of oxygen reduction reaction (ORR) catalysts. In this work, a PtCuNi/C-WO3-x catalyst is designed employing non-stoichiometric WO3-x with abundant oxygen vacancies (Ovac). The WO3-x can dramatically improve the stability of PtCuNi without sacrificing the activity. Theoretical calculation suggests a decreased vacancy formation energy of W in WO3-x at the presence of Ovac, as well as increased vacancy formation energies of Pt/Cu/Ni in PtCuNi alloy particles with the existence of surface W dopant. Combined with the experimental discovery of slower dissolution rates of metals in PtCuNi/C-WO3-x catalyst, a dissolution-induced stability enhancement mechanism is proposed, whereby facilitated dissolution of W atoms from WO3-x bulk could re-deposit on Pt-alloy surface and inhibit the dissolution of catalytically active metal atoms, revealing a dynamic process that enhances the stability. The PtCuNi/C-WO3-x also shows great potential to be used as cathode catalyst in membrane electrode assembly for high-temperature proton exchange membrane fuel cells.
Structural design is an effective way to realize the functional construction of hole transporting materials (HTMs). In order to have an insight into the relationship between molecular structure and function of HTMs, three isomeric HTMs (RQ1, RQ2 and RQ3) are constructed with functional group of dibenzothiophene which is connected to different positions on the side chains of carbazole-aromatic derivatives. In combination with computational simulation and experimental study, although the isomeric RQ1–RQ3 with the same molecular formula exhibit similar frontier molecular orbital energy levels and optical absorption, their hole transporting ability and interaction at perovskite/HTMs interface in perovskite solar cells (PSCs) are completely different. In comparison with the RQ2 (18.69%) and RQ3 (22.56%), the results indicate that the molecule RQ1 in PSCs application can yield higher power conversion efficiency (23.50%) because of its higher hole mobility and effective charge transfer at perovskite/HTMs interface. Moreover, the mutually corroborating between the computational simulation and the experimental results demonstrate the reliability of the theoretical model for molecular design of isomeric HTMs. This strategy of obtaining high-performance HTMs through simple structural design is expected to inspire researchers to further optimize the efficiency of PSCs.
Traditional polycrystalline P2 layered oxides face challenges such as irreversible phase transitions, poor air stability, and structural distortion, which negatively impact their electrochemical performance. In this study, a single-crystal material, P2-Na2/3Ni1/4Mn2/3Mg1/12O2 (SC-NMM), was synthesized using co-precipitation coupled with the molten salt method. Owing to the strong integrity and high thermal stability of the main {001} planes of the large-sized single crystal, SC-NMM exhibits a high reversible specific capacity (173.5 mAh/g at 20 mA/g) and stable cycle performance (93.38% capacity retention after 100 cycles at 100 mA/g) at high voltage. Additionally, the Na-ion full cell constructed with the SC-NMM cathode and hard carbon anode demonstrates a cathode energy density of 397.4 Wh/kg. The excellent electrochemical performance of SC-NMM originates from the reversible anion redox and single-phase solid solution reaction mechanism. This work provides a reference for synthesizing single-crystal layered transition metal oxides with high electrochemical performance by eliminating irreversible phase transitions through crystal orientation modulation.
Aqueous zinc-ion batteries (AZIBs) have emerged as strong contenders for large-scale energy storage solutions, attributed to their cost-effectiveness and enhanced safety profiles. Nevertheless, their widespread adoption is currently hindered by their poor performance in low-temperature conditions. Herein, an electrolyte is developed by utilizing weakly solvated and film-forming molecule dimethyl sulfite (DMS) to achieve smooth de-solvation and high ionic conductivity at low temperature. The DMS disrupts the hydrogen bonding network of water and lowers the freezing point of the electrolyte to -40.9 ℃. The designed electrolyte achieves ionic conductivity up to 10.75 mS/cm at -30 ℃. Due to the chemical reactivity of DMS and trifluoromethanesulfonate anions in the Zn2+-solvation shell, a ZnF2-ZnS hybrid solid electrolyte interphase (SEI) is successively generated on Zn metal surface. Mechanistic studies reveal that such robust hybrid interphase can promote Zn2+ desolvation and rapid Zn2+ transport. In addition, the addition of DMS effectively suppresses the dendritic growth, hydrogen evolution reaction (HER), and corrosion-induced passivation on the anode surface, facilitating long-term cycling at subzero temperatures. At -40 ℃, the Zn//Zn symmetrical cell cycles for 1200 h at 0.5 mA/cm2 and 0.5 mAh/cm2, and the Zn//NVO cell achieves an ultra-long cycle life of 1000 cycles with a high capacity retention of 82.89% at 1 A/g.
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