Immobilizing Redox‐Active Tricycloquinazoline into a 2D Conductive Metal–Organic Framework for Lithium Storage

Abstract

Heteroaromatic-conjugated aromatic molecules have inspired numerous interests in rechargeable batteries like Li-ion batteries, but were limited by low conductivity and easy dissolution in electrolytes. Herein, we immobilize a nitrogen-rich aromatic molecule tricycloquinazoline (TQ) and CuO 4 unit into a two-dimensional (2D) conductive metalorganic framework (MOF) to unlock their potential for Li + storage. TQ was identified redox activity with Li + for the first time. With a synergistic effect of TQ and CuO 4 unit, the 2D conductive MOF, named Cu-HHTQ (HHTQ = 2,3,7,8,12,13hexahydroxytricycloquinazoline), can facilitate the Li + /e À transport and ensure a resilient electrode, resulting in a high capacity of 657.6 mAh g À1 at 600 mA g À1 with extraordinary high-rate capability and impressive cyclability. Our findings highlight an efficient strategy of constructing electrode materials for energy storage with combining multiple redox-active moieties into conductive MOFs.

2D Metal–Organic Framework Cu3(HHTT)2 Films for Broadband Photodetectors from Ultraviolet to Mid‐Infrared

“…The peak assignments are done by checking the peak positions from previously reported powder XRD patterns. [2,6,22] Only one peak at 2θ = 27.9° can be observed in the out-of-plane XRD pattern, which can be assigned to (001) diffraction. In contrast, three peaks at 2θ = 4.2°, 8.5°, 13.6° can be found in the inplane XRD pattern, which can be indexed as (100), ( 200), (220) planes.…”

“…The obtained XRD peaks are all consistent with those reported in literature. [ 2,6,22 ] The significant difference between in‐plane and out‐of‐plane XRD profiles indicates the highly oriented Cu 3 (HHTT) 2 thin films prepared by this method. The relatively weak XRD signal can be attributed to small grain size and thin thickness of the film, which is similar to XRD spectra of other 2D c‐MOF films.…”

“…[10,19] Various 2D c-MOFs thin films can be grown based on different bottom-up schemes, such as layer-by-layer assembly, liquid-air interface, liquidliquid interface, and face-to-face confined growth. [14,20,21] 2D c-MOF Cu 3 (HHTT) 2 (HHTT: 2,3,7,8,12,13-hexahydroxy tetraazanaphthotetraphene) has been reported to be an efficient electrocatalyst for CO 2 reduction and electrode materials for Li storage, [2,6,22] which features excellent in-plane and out-of-plane crystallinity due to the large ligand core with heteroatoms. The 2D c-MOF is expected to have high conductivity because of efficient in-plane d-π conjugations and strong interlayer π-π interactions.…”

Eight‐Electron Redox Cyclohexanehexone Anode for High‐Rate High‐Capacity Lithium Storage

“…As Figure 2e demonstrates, the deduced b ‐values of six redox peaks are all between 0.75 and 1.0, indicative of a mixed electrochemical process combining diffusion‐controlled and capacitive mechanisms. To further quantitatively distinguish the contribution of diffusion‐controlled capacity and capacitance to the overall capacity at various current densities, the relationship i p = aν b can be rewritten as i = k 1 ν + k 2 ν 1/2 , where k 1 ν and k 2 ν 1/2 are capacitance and diffusion‐controlled capacity, [ 34,37,38 ] respectively. By plotting v 1/2 versus i / v 1/2 , k 1 and k 2 can be respectively quantified from the slope and the y ‐axis intercept point.…”

“…where k 1 ν and k 2 ν 1/2 are capacitance and diffusion-controlled capacity, [34,37,38] respectively. By plotting v 1/2 versus i/v 1/2 , k 1 and k 2 can be respectively quantified from the slope and the y-axis intercept point.…”