Transcending Conventional Carbon Nitrides: Three‐in‐One Multi‐Molecular Synergy Engineering in Covalent Heptazine Framework Unlocks Roust High‐Rate Sodium‐Ion Storage

ABSTRACT Carbon nitrides (CNs), particularly graphitic carbon nitride (g‐C 3 N 4 ), show promise as electrodes for sodium‐ion batteries (SIBs) due to exceptional stability and Na + storage potential. However, the low intrinsic conductivity and insufficient activity of CNs hamper the realization of both high capacity and high stability. Herein, this work proposes a multi‐active‐function modulation strategy to solve such challenges by integrating heptazine with functional conductive modules via active linkers, as exemplified by the rational design of a benzothiadiazole cooperated with alkynyl bifunctionalized covalent heptazine framework (BTA‐CHF). This covalent linkage, via the alkynyl bridge, creates a fully electron‐conductive skeleton densely packed with multiple Na + ‐storage sites. Thus, as a SIBs anode, BTA‐CHF renders record‐high performance with exceptional capacity (912.1 mAh g −1 at 0.1 A g −1 ), outstanding rate property (273.8 mAh g −1 at 10.0 A g −1 ), and inspiring cyclability (∼93.9% capacity sustainability through 20 000‐cycles at 10 A g −1 ). More impressively, the BTA‐CHF//Na 3 V 2 (PO 4 ) 3 full battery exhibits a notable capacity of 836.8 mAh g −1 at 0.1 A g −1 , remarkable high‐rate performance of 166.9 mAh g −1 at 10 A g −1 , and maintains 143.2 mAh g −1 after 1000 cycles at 10 A g −1 . This work demonstrates a novel approach to engineer advanced CNs electrodes for high‐efficiency SIBs.