Electrochemical Activity of Nitrogen‐Containing Groups in Organic Electrode Materials and Related Improvement Strategies

Abstract

In recent years, due to their structural diversity, adjustability, versatility, and excellent electrochemical properties, organic compounds with nitrogen‐containing groups (OCNs) have become some of the most promising organic electrode materials. The nitrogen‐containing groups acting as electrochemical active sites include carbon–nitrogen groups, nitrogen–nitrogen groups, nitrogen–oxygen groups in OCNs, and nitrogen‐containing groups in covalent organic frameworks. The molecular structure regulation of OCNs with nitrogen‐containing groups acting as electrochemical active centers can suppress dissolution in electrolytes, increase electronic conductivity, and improve the kinetics of redox reactions. The kinetics behavior and electrochemical characteristics of OCN electrode materials in alkali metal rechargeable batteries with organic electrolytes are reviewed, and the related relationships between the structure and electrochemical properties of OCNs are the core of this review. Herein, the electrochemical reaction mechanisms and the strategies to improve the electrochemical activity of nitrogen‐containing groups in OCNs are clarified, and the conjugate molecular structure of OCNs is shown to be an important direction for improvement. These results will have implications for research on electrode materials and provide more choices for rechargeable batteries. Moreover, this work will guide the study of more efficient OCNs that can be used as electrode materials.

Organic Negative Electrode Materials for Metal‐Ion and Molecular‐Ion Batteries: Progress and Challenges from a Molecular Engineering Perspective

“…The redox process proceeds akin to imine-based compounds, for which the nitrogen in azomethine group (CN) reacts according to an n-type redox mechanism (Figure 8). [52,67,[222][223][224][225][226] For process reversibility, the Schiff bases must be integrated within a 10-π electron unit (NCHΦCHN) in order to abide by the Hückel's rule of aromaticity. [37] By way of comparison, the CN functional groups are easier to reduce than the homologous CO ones, [227] and their redox potential could be tuned through intramolecular hydrogen bonds or lengthening the conjugation chain.…”

“…[1] In the light of promoting efficient, safe, and low-polluting electrochemical energy storage systems, [2] electroactive organic materials (EOMs) have sparked considerable attention in recent compounds, [53] and the most recently reported N-substituted salts of viologen derivatives. [52] Since 2008 (a year witnessed as the modern area revival of EOMs), dozens of review articles have been published from different perspectives (e.g., molecular design, [20,22,23,27,41,42,49,50,[54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] sustainability, [70,71] opportunity, [3,[72][73][74] practicability, [75][76][77][78] and technology [79][80][81][82] ). It is worth noting that most reviews are focused on OPEMs with less consideration to ONEMs, except two reviews dedicated to ONEMs for Na/K-ion batteries, [37,83] yet presenting only a summary of advances and no critical discussion or suggested solutions for remai...…”

Covalent Organic Framework with Highly Accessible Carbonyls and π‐Cation Effect for Advanced Potassium‐Ion Batteries

“…[27] In comparison to carbon materials, COF enables the building of a resilient framework with better structural stability and provides open pathways for facile ion transfer. [28] Additionally, COF has a large reversible storage capacity due to the abundance of active sites, and the unique hierarchical pore structure of the framework improves ion transfer while efficiently avoiding volume expansion. [29] However, the 2D layers of bulk COF are always densely packed due to the strong π-π stacking interactions.…”

Probing Mechanistic Insights into Highly Efficient Lithium Storage of C60 Fullerene Enabled via Three‐Electron‐Redox Chemistry

“…[9,10] In recent years, the metal-free organic (MFO) materials composed of abundant elements (C, H, O, N, S) have emerged as novel cathode materials for rechargeable batteries due to their renewability, structural diversity and componential tunability over the aforementioned conventional cathode materials. [11][12][13][14][15][16][17] These MFO cathode materials mainly fall into three types: n-type, p-type, and bipolar depending on the accessible charge-state of the electroactive sites within. [12,18] In the charging process, the p-type materials, such as polyphenylamine, coronene, and its analogues, can be oxidized accompanied by anion (such as PF 6 − and ClO 4 − ) intercalation for dual-ion batteries (DIBs).…”