RESUMEN
Aqueous zinc-ion batteries (ZIBs) are the new generation electrochemical energy storage systems. Recently, two-dimensional conductive metal-organic frameworks (2D c-MOFs) are attractive to serve as cathode materials of ZIBs due to their compositional diversity, abundant active sites, and excellent conductivity. Despite the growing interest in 2D c-MOFs, their application prospects are still to be explored. Herein, a tetraoxa[8]circulene (TOC) derivative with unique electronic structure and interesting redox-active property are synthesized to construct c-MOFs. A series of novel 2D c-MOFs (Cu-TOC, Zn-TOC and Mn-TOC) with different conductivities and packing modes are obtained by combining the linker tetraoxa[8]circulenes-2,3,5,6,8,9,11,12-octaol (8OH-TOC) and corresponding metal ions. Three c-MOFs all exhibit typical semiconducting properties, and Cu-TOC exhibits the highest electrical conductivity of 0.2 S cm-1 among them. Furthermore, their electrochemical performance as cathode materials for ZIBs have been investigated. They all performed high reversible capacity, decent cycle stability and excellent rate capability. This work reveals the key insights into the electrochemical application potential of 2D c-MOFs and advances their development as cathode materials in ZIBs.
RESUMEN
Conductive coordination polymers (c-CPs) are promising electrode materials for supercapacitors (SCs) owing to their excellent conductivity, designable structures and dense redox sites. However, despite their high intrinsic density and outstanding electrical properties, nonporous c-CPs have largely been overlooked in SCs because of their low specific surface areas and deficient ion-diffusion channels. Herein, we demonstrate that the nonporous c-CPs Ag5BHT (BHT = benzenehexathiolate) and CuAg4BHT are both battery-type capacitor materials with high specific capacitances and a large potential window. Notably, nonporous CuAg4BHT with bimetallic bis(dithiolene) units exhibits superior specific capacitance (372 F g-1 at 0.5 A g-1) and better rate capability than isostructural Ag5BHT. Structural and electrochemical studies showed that the enhanced charge transfer between different metal sites is responsible for its outstanding capacitive performance. Additionally, the assembled CuAg4BHT//AC SC device displays a favorable energy density of 17.1 W h kg-1 at a power density of 446.1 W kg-1 and an excellent cycling stability (90% capacitance retention after 5000 cycles). This work demonstrates the potential applications of such nonporous redox-active c-CPs in SCs and highlights the roles of bimetallic redox sites in capacitive performance, which hold promise for the future development of c-CP-based energy storage technologies.
RESUMEN
Crystalline organic metal chalcogenides (OMCs) are a class of organic-inorganic hybrid semiconducting materials with continuous M-X (X = S, Se, Te) networks formed by the combination of metal nodes and chalcogen atoms from the organic ligands, which display great potentials in the fields of optoelectronics, catalysis, sensing, as well as energy conversion and storage. Here, we synthesized a wave-like 2D OMC material, [(AgBF4)2Me6BHS]n (Ag-BHSMe), from AgBF4 and 1,2,3,4,5,6-hexa(methylselanyl)benzene (Me6BHS) through a simple homogeneous reaction. In the solid state, Ag-BHSMe exhibits both fluorescence emission at room temperature and phosphorescent emission at 77 K. TEM, SEM, and confocal microscopy revealed that it is an intrinsic blue luminescent microcrystalline material. In addition, we found that it exhibited a highly selective fluorescence enhancement response to Pb2+ in an aqueous solution in the range of 10-4 to 10-2 mol L-1, which demonstrates its potential as a turn-on probe for the detection of lead ions.