Functionalized Graphene Quantum Dots Modified Dioxin‐Linked Covalent Organic Frameworks for Superior Lithium Storage

Abstract

Covalent organic framework, as an emerging porous nano-frame structure with pre-designed structure and custom properties, has been demonstrated as a prospective electrode for rechargeable Li-ion batteries. For improving the reversible capacity and long-term cycle stability of COF materials, we propose a GQDs modified COF material (COF-GQDs) and apply it as the anode for LIBs for the first time. This COF-GQDs electrode delivers enhanced long-term cycling performance with a large capacity of ~820 mAh g À 1 after 300 cycles at 100 mA g À 1 and an improved rate performance. The enhanced lithium-storage performance, in terms of obviousshortened activation process and high reversible capacities, can be attributed to the modification of carboxyl GQDs, which would activate more active sites (activated C=C groups from benzene rings) for lithium-storage, and provide fast lithiumion transportation kinetic. Besides, the decreased interphase resistance, enhanced electronic conductivity, and prevented aggregation of needle-flake COF structure, originated from the addition of GQDs, which lead to the enhanced improved cycling stability of the COF-GQDs electrode. This manuscript can promote the further exploration on the design of COFrelated materials with modification of functionalized carbonaceous materials to achieve enhanced lithium-storage properties for next-generation energy storage.

Design of 3D Metal–Organic Material with Multiple Redox-Active Sites for High-Performance Lithium-Ion Batteries

“…In Figure b,c, the capacity of the initial several cycles is low, while the discharge capacities in the first several cycles at the same current density are higher. This behavior can be attributed to the phenomenon of formation of SEI and activation of the electrode. , To evaluate the rate performance, the lithium storage capability of Mn-3D was examined at various current densities (Figure d). Mn-3D showed the reversible capacities of 650, 566, 537, 515, 471, and 390 mA h g –1 at current densities of 50, 100, 200, 300, 500, and 1000 mA g –1 , respectively.…”

Application of New COF Materials in Secondary Battery Anode Materials

“…The aminated 2D MXene provides reactive sites for the interface-initiated imine In addition, COFs are often compounded with graphene, carbon nanotubes, MXene, and other materials. To improve the capacity and long cycle stability of COF materials, Wang et al [36] modified dioxin-chain COF with graphene quantum dots. This composite material introduced graphene quantum dots rich in carboxyl groups, thus changing the surface structure of COF, exposing more active sites, and promoting the transport dynamics of lithium ions.…”

Covalent Organic Frameworks Meet Titanium Oxide

“…Applied to the anode of lithium-ion batteries, this COF-GQD electrode exhibited enhanced long-term cycling performance with a capacity of 820 mA•h•g −1 after 300 cycles at the specific current of 100 mA•g −1 and a high rate performance. 90 Zhang and co-workers prepared a 2D COF (TpPa-1-COF) through the condensation reaction of 1,3,5triformylphloroglucinol (Tp) and 1,4-diaminobenzene, then ZnCdS QDs were grown onto the surface of TpPa-1-COF to obtain a ZnCdS/TpPa-1-COF composite. The prepared ZnCdS/TpPa-1-COF showed high performance for photocatalytic H 2 production.…”

“…Wang and co-workers synthesized a dioxin-linked COF with a large π–π conjugated structure by a nucleophilic reaction between tetrafluoroterephthalonitrile (TFPN) and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and then introduced −COOH-functionalized graphene quantum dots (GQDs) in the prepared COF to obtain a COF-GQD composite. Applied to the anode of lithium-ion batteries, this COF-GQD electrode exhibited enhanced long-term cycling performance with a capacity of 820 mA·h·g –1 after 300 cycles at the specific current of 100 mA·g –1 and a high rate performance . Zhang and co-workers prepared a 2D COF (TpPa-1-COF) through the condensation reaction of 1,3,5-triformylphloroglucinol (Tp) and 1,4-diaminobenzene, then ZnCdS QDs were grown onto the surface of TpPa-1-COF to obtain a ZnCdS/TpPa-1-COF composite.…”