Exfoliated Triazine‐Based Covalent Organic Nanosheets with Multielectron Redox for High‐Performance Lithium Organic Batteries

Abstract

The development of the next‐generation lithium ion battery requires environmental‐friendly electrode materials with long cycle life and high energy density. Organic compounds are a promising potential source of electrode materials for lithium ion batteries due to their advantages of chemical richness at the molecular level, cost benefit, and environmental friendliness, but they suffer from low capacity and dissatisfactory cycle life mainly due to hydrophobic dissolution in organic electrolytes and poor electronic conductivity. In this work, two types of triazine‐based covalent organic nanosheets (CONs) are exfoliated and composited with carbon nanotubes. The thin‐layered 2D structure for the exfoliated CONs can activate more functional groups for lithium storage and boost the utilization efficiency of redox sites compared to its bulk counterpart. Large reversible capacities of above 1000 mAh g−1 can be achieved after 250 cycles, which is comparable to high‐capacity inorganic electrodes. Moreover, the lithium‐storage mechanism is determined to be an intriguing 11 and 16 electron redox reaction, associated with the organic groups (unusual triazine ring, piperazine ring, and benzene ring, and common CN, NH groups).

Covalent Organic Framework Derived Boron/Oxygen Codoped Porous Carbon on CNTs as an Efficient Sulfur Host for Lithium–Sulfur Batteries

“…The intensity of the D band and G band represent the characteristic of a defective graphite structure and the sp 2 hybrid in-plane stretching vibration of C atom, respectively. [42] The intensity ratios of these two bands (I D /I G ) are calculated to be 0.93 and 0.84 for the BOC@CNT and BOC/CNT, respectively, indicating there are more defects for BOC@CNT. EA indicates the weight contents of sulfur, carbon, and hydrogen in BOC@CNT (C: 92.31%; H: 2.42%), BOC/CNT/S (S: 64.5%; C: 28.95%; H: 0.43%), and BOC@CNT/S (S: 68.3%; C: 27.52%; H: 0.25%), as listed in Table S1 (Supporting Information).…”

Molecular Design Strategies for Electrochemical Behavior of Aromatic Carbonyl Compounds in Organic and Aqueous Electrolytes

“…[161][162][163] In ACCs, there is a highly crystalline COF structure in the highly reversible polymerization of imide and some amino groups. COFs have many properties, such as a high specific surface area, uniform pore size, high thermal stability, low density, and diverse structure.…”

High‐Lithium‐Affinity Chemically Exfoliated 2D Covalent Organic Frameworks

“…Covalent organic frameworks (COFs) are a class of 2D or 3D crystalline and porous polymeric materials, which can serve as potential electrode materials for energy storage applications . The stable porous COFs structure provides an open channel for the facilitated infusion of the electrolyte and the transport of ions/electrons.…”

“…[25,26] Covalent organic frameworks (COFs) are a class of 2D or 3D crystalline and porous polymeric materials, which can serve as potential electrode materials for energy storage applications. [27][28][29] The stable porous COFs structure provides an open channel for the facilitated infusion of the electrolyte and the transport of ions/electrons. Currently, few COFs have been investigated as electrode materials or electrode support for lithium storage, [30][31][32][33][34][35][36][37][38] which usually exhibited enhanced electrochemical properties compared to common organic electrodes.…”