Conjugated Ladder-Type Polymer with Hexaazatriphenylene Units as a Cathode Material for Lithium, Sodium, and Potassium Batteries

Abstract

A ladder-type conjugated polymer with hexaazatriphenylene moieties is reported, and its application as a cathode material for Li-, Na-, and K-based batteries is assessed. The material demonstrates specific capacities of 170–180 mA h g–1 at 0.1 A g–1, and up to 113 mA h g–1 at 5 A g–1 (charge/discharge in ∼80 s). It also shows superior cycling stability, especially in potassium cells that show no capacity fade after 4000 cycles at 5 A g–1. Charge–discharge processes of the material are probed using operando Raman spectroscopy.

Refreshing the Legacy of Rudolf Nietzki: Benzene-1,2,4,5-tetramine and Related Compounds

“…Nietzki (1847–1917) is an unfamiliar figure to many modern organic chemists, but he made farsighted contributions in areas of enduring importance. − Nietzki’s impact can be measured by the frequency with which compounds first made in his research group are used today. In particular, BTA ( 1 ) and its derivatives are at the center of an imposing array of projects, including studies in which the compounds are used as precursors of redox-active materials, − ligands in coordination chemistry, − components for making metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) by modular construction, − monomers for producing polymers, − components of switches and sensors, , precursors for synthesizing diverse heterocyclic compounds, − and enzyme inhibitors for use in treating cancer …”

Calix[8]quinone: A new promising macrocyclic molecule as an efficient organic cathode in lithium ion batteries with a highly‐concentrated electrolyte

“…However, the dissolution of organic materials in organic secondary batteries still frustrates many scientists. Particularly, small carbonyl compounds are readily soluble, leading to poor cycling stability 12–16 . In response to this issue, many methods have been explored, including molecular structure optimization, 17,18 molecular polymerization, 19–23 lithium salt formation, 24–26 and carbon materials composite, and so forth 27–29 .…”

“…Particularly, small carbonyl compounds are readily soluble, leading to poor cycling stability. [12][13][14][15][16] In response to this issue, many methods have been explored, including molecular structure optimization, 17,18 molecular polymerization, [19][20][21][22][23] lithium salt formation, [24][25][26] and carbon materials composite, and so forth. [27][28][29] Given their potential practical application with less environmental pollution and possible reusability, it is imperative to design eco-friendly organic materials with high theoretical capacity, suitable structural stability, and reasonable energy density.…”

“…The 1 H NMR spectrum of C8Q (in CF 3 COOD) is shown in Figure S4 with the peaks of δ 6.90 (s, 16H, CH C ) and δ 3.74 (s, 16H, CH 2 ). Figure S5 is the 13 The electrochemical performance of C8Q was firstly evaluated in 1 M LiPF 6 -EC/DMC electrolyte. Details in preparing electrodes and assembling cells have been provided in the SI.…”

Thermoelectric Performance Enhancement of p-Type Pyrrolo[3,2-b:4,5-b′]bis[1,4]benzothiazine Conjugated Ladder Polymer by Pendant Group Engineering

“…The rigid coplanar conformation can improve intrachain delocalization of frontier molecular orbitals to facilitate the intrachain charge transfer, as well as enhanced π–π stacking interactions to improve interchain electronic coupling. − In addition, the double-stranded polymer backbone and strong π–π stacking interactions make it more difficult to break the polymer structure, resulting in higher thermal stability than the conventional single-stranded conjugated polymer. These advantageous features render conjugated ladder polymers great potential in organic electronic devices including organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), , organic electrochemical transistors (OECTs), , organic thermoelectrics (OTEs), − lithium-ion batteries (LIBs), − photocatalysts, , graphene nanoribbons, , and solar cells. , However, the efficient synthesis and structural characterization of these materials are challenging for further application and development due to their extremely poor solubility in conventional solvents, including tetrahydrofuran (THF), chloroform, chlorobenzene, dimethylformamide (DMF), and N -methylpyrrolidone (NMP). The classical strategy is to introduce solubilizing groups to the backbone for improving solubility and processability. − However, this strategy usually needs to go through multiple-step synthesis via a prepolymer intermediate and further ring closure to form final ladder polymers.…”