A Generalizable Active‐Site Blocking Strategy Enables High Initial Coulombic Efficiency in Mononitrogen‐Containing Organic Cathodes

Abstract

ABSTRACT Mononitrogen‐containing aromatic compounds, exemplified by carbazole (CZ) and triphenylamine, are emerging as promising high‐potential candidates (3.6–4.3 V vs. Li + /Li) for p‐type anion‐storage electrode materials. However, the inherent reactivity of their para positions at elevated potentials (>4 V) induces undesirable electropolymerization, leading to severe low initial coulombic efficiency (ICE). Herein, we propose an active‐site blocking strategy to fundamentally address this critical challenge through molecular engineering. Specifically, we develop a CZ‐based organic polymer, poly[5‐(9‐ethyl‐9H‐carbazol‐3‐yl)‐5,10‐dihydrophenazine] (p‐ECZDPZ), tailored as the model system to validate the efficacy of our proposed strategy. By strategically incorporating 5,10‐dihydrophenazine and ethyl group into its structure, the active para positions of the CZ moieties are effectively blocked. This enables a superior ICE of 86% without requiring any pretreatment, surpassing other known CZ‐based organic electrode materials to date. The constructed Li‐based dual‐ion full batteries (LDIBs) achieve a peak discharge capacity of 204 mAh g −1 , an ICE of 84%, and a stable operation over 20 000 cycles. At high cathode mass loading, the LDIBs demonstrate an energy density of 445 Wh kg −1 while retaining no capacity decay for 8000 cycles. Pouch‐type full cells achieve direct activation during the first charge process, realizing an energy density of 305 Wh kg −1 cathode .