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Phenothiazine-Based π-Extended Covalent Network Cathodes for Lithium Dual-Ion Batteries with High Energy Density and Fast Charging
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DOI:10.1016/j.ensm.2026.105449.png)
Abstract
En 中文
P-type organic cathodes have shown great promise for lithium dual-ion batteries (LDIBs), yet their practical deployment remains severely constrained by insufficient operating voltages, sluggish ion kinetics, and structural instability under high-rate conditions. Herein, we report a rational molecular design of a phenothiazine-based π-extended covalent network cathode, designated as Poly(3-methyl-7-(13-methyldibenzo[b,i]phenazine-6(13H)-yl)-10-(p-tolyl)-10H-phenothiazine) (PMPPTZ). Distinct from conventional linear analogues, PMPPTZ features a robust conjugated network framework wherein 6,13-dihydrodibenzo[b,j]phenazine (DDPZ) units are covalently bridged by phenothiazine nodes. This unique structure not only extends the π-electron delocalization pathway to enhance electronic conductivity and redox potential, but also constructs an open porous architecture that facilitates rapid ion diffusion. Meanwhile, the incorporation of sulfur atoms further promotes charge delocalization and facilitates electron transport. As a comparison, its linear analogue named Poly(3,10-dimethyl-7-(13-methyldibenzo[b,i]phenazine-6(13H)-yl)-10H-phenothiazine) (PDMPTZ) is synthesized. Comparative electrochemical evaluations demonstrate that PMPPTZ significantly outperforms PDMPTZ, delivering a high energy density of 614 Wh kg-1 and operating at a high rate of 57 C in half cells. The full cells assembled with graphite anodes and PMPPTZ cathodes exhibit a peak discharge capacity of 167 mAh g-1 and an energy density of 564 Wh kg-1cathode, maintaining stability over 1000 cycles.
Journal
IF:
20.2
Papers:
5.6K
Citations:
6.3W
