Polyanthraquinone-Triazine—A Promising Anode Material for High-Energy Lithium-Ion Batteries

Abstract

A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of CN groups, CO groups, and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and bring a theoretical specific capacity of 1450 mA h g −1 . The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity. The highly conductive conjugated polymer skeleton enables fast electron transport to facilitate the Li storage. In this way, the polymer electrode shows a large specific capacity and favorable cycling and rate performance, making it an appealing anode choice for the next-generation high-energy batteries.

Exploiting Polythiophenyl‐Triazine‐Based Conjugated Microporous Polymer with Superior Lithium‐Storage Performance

“…Particularly, the microporous structure could contribute large available space to accommodate the volume change during the repetitive charge/discharge operations. Moreover, the fully exposed surface area could offer more redox‐active sites and shorten the Li + transport distance, realizing fast reaction kinetics . In addition, the highly π‐conjugated skeleton with natural insolubility of active material in organic electrolytes will enhance the cyclability .…”

“…The excellent thermal and chemical stability of TzThBT can be attributed to its highly crosslinked structure and rigid molecular skeleton . No clear diffraction peaks could be observed in the powder (P)XRD profile (Figure S3 in the Supporting Information), indicating the amorphous nature of the polymer, which is similar to most reported CMP frameworks . SEM images demonstrate that TzThBT has a relatively uniform nanoparticle morphology (Figure S4 in the Supporting Information).…”

“…Figure a displays the cyclic voltammetry (CV) profiles of the TzThBT anode at a scan rate of 0.1 mV s −1 with an operating voltage from 0.005 to 3 V (vs. Li + /Li). A strong cathodic peak at 0.3–1.2 V was observed during the first cathodic scanning, which is mainly ascribed to the formation of a solid electrolyte interphase (SEI) film on the electrode–electrolyte interface . This strong cathodic peak disappeared in the following cycles, demonstrating that the formed SEI film in the first cycle is stable and prevents the further decomposition of electrolytes in the following cycles.…”

“…The building blocks of Tz, Th, and BT have been employed to produce many porous polymer anodes for LIBs owing to their high n‐type doping/dedoping abilities, such as the Tz‐containing polymers PAT‐COF, E‐SNW‐1/CNT, and f ‐CTF‐1, the Th‐containing polymers P33DT, PTTE, DBD‐CMP2, and TThPP, and the BT‐containing polymer PDCzBT . However, all of these polymers only contain one of the three building blocks.…”

“…Kang et al. developed a conjugated polymeric anode, polyanthraquinone‐triazine (PAT), with abundant C=N, C=O and benzene functional modules and obtained a high discharge capacity of 1450 mAh g −1 at 200 mA g −1 . Considering the structural diversity and designability of CMPs, further enhancement of the electrochemical performance for LIBs might be anticipated by CMP electrodes.…”