Anchoring π‐d Conjugated Metal–Organic Frameworks with Dual‐Active Centers on Carbon Nanotubes for Advanced Potassium‐Ion Batteries

Abstract

Potassium‐ion batteries (PIBs) are gradually gaining attention owing to their natural abundance, excellent security, and high energy density. However, developing excellent organic cathode materials for PIBs to overcome the poor cycling stability and slow kinetics caused by the large radii of K+ ions is challenging. This study demonstrates for the first time the application of a hexaazanonaphthalene (HATN)‐based two‐dimensional π‐d conjugated metal‐organic framework (2D c‐MOF) with dual‐active centers (Cu‐HATNH) and integrates Cu‐HATNH with carbon nanotubes (Cu‐HATNH@CNT) as the cathode material for PIBs. Owing to this systematic module integration and more exposed active sites with high utilization, Cu‐HATNH@CNT exhibited a high initial capacity (317.5 mA h g−1 at 0.1 A g−1), excellent long‐term cycling stability (capacity retention of 96.8% at 5 A g−1 after 2200 cycles), and outstanding rate capacity (147.1 mA h g−1 at 10 A g−1). The reaction mechanism and performance were determined by combining experimental characterization and density functional theory (DFT) calculations. This contribution provides new opportunities for designing high‐performance 2D c‐MOF cathodes with multiple active sites for PIBs.This article is protected by copyright. All rights reserved

Imino-Linked Carbonyl-Enriched Polymer as a High-Performance Cathode Material for Lithium-Ion Batteries

“…27 The almost overlap from the second to the fifth cycles in CV demonstrate the high reversibility of the redox reaction during the charge and discharge processes. 29 The galvanostatic charge−discharge result is illustrated in Figure 3b, showing that a high discharge capacity of 240.2 mA h g −1 can still be realized after 100 cycles. Due to the presence of 60 wt % acetylene black in the PDABQ cathode, the electrochemical performance of acetylene black was investigated to elucidate the actual capacity of PDABQ.…”

“…Consequently, the occurrence of multiple redox peaks was the result of the continuous lithiation/delithiation of PDABQ in the CV curves . The almost overlap from the second to the fifth cycles in CV demonstrate the high reversibility of the redox reaction during the charge and discharge processes …”

Conductive Metal–Organic Framework with Superior Redox Activity as a Stable High-Capacity Anode for High-Temperature K-Ion Batteries

“…The conductive HAN-Cu-MOF is demonstrated to be a stable high-capacity KIB anode at both room and high temperatures. The electrodes were prepared based on the pristine bulk MOF rather than the modified composition like the previously reported MOF@CNT or MOF@Graphene composites. − Generally, the fabrication of these MOF/carbon composites necessitated tedious operations and strict synthesis control, thus leading to low efficiency and low yield. We used the hybrid binder of carboxymethylcellulose sodium (CMC)/styrene butadiene rubber (SBR) to prepare the anode films.…”

De Novo Design and Facile Synthesis of Highly Crystalline 2D Conductive Metal–Organic Frameworks: A “Rotor-Stator” Strategy

“…1,2 Due to the robust orbital hybridization between metal ions and ligands, coupled with the formation of one-dimensional columnar channels, 2D c-MOFs can efficiently transport charge carriers both along the πstacking direction and over the 2D plane, endowing them with higher electrical conductivity and charge mobility than 3D MOFs. 3−7 However, there are still several urgent issues that need to be addressed, although their merits make them ideal candidates in the field of sensing, 8,9 spintronics, 7,10,11 and electrochemistry, 12,13 among others. 14,15 First, up to date, the majority of reported 2D c-MOFs have been synthesized using a limited range of planar conjugated ligands, including tetra-/ hexa-substituted benzene, 16,17 hexa-substituted triphenylene, 18,19 octa-substituted phthalocyanine, 20,21 and dodeca-substituted coronene.…”

“…As a burgeoning category of multifunctional crystalline porous materials, two-dimensional conductive metal–organic frameworks (2D c -MOFs) are commonly self-assembled from π-conjugated ligands and metal ions in square-planar coordination mode, exhibiting layered structures similar to graphite and other inorganic 2D crystals. , Due to the robust orbital hybridization between metal ions and ligands, coupled with the formation of one-dimensional columnar channels, 2D c -MOFs can efficiently transport charge carriers both along the π-stacking direction and over the 2D plane, endowing them with higher electrical conductivity and charge mobility than 3D MOFs. − However, there are still several urgent issues that need to be addressed, although their merits make them ideal candidates in the field of sensing, , spintronics, ,, and electrochemistry, , among others. , First, up to date, the majority of reported 2D c -MOFs have been synthesized using a limited range of planar conjugated ligands, including tetra-/hexa-substituted benzene, , hexa-substituted triphenylene, , octa-substituted phthalocyanine, , and dodeca-substituted coronene. , The use of planar conjugated ligands is advantageous for augmenting π-electron delocalization and improving the conductivity of 2D c -MOFs. However, their poor solubility in common organic solvents raises challenges in the synthesis of 2D c -MOFs.…”