Highly Efficient and Stable Capacitive Deionization based on a
Flower-like Conjugated Polymer with Double Active-sites
Abstract
Organic materials, with low environmental impact and adaptable
structures, are attractive for Hybrid capacitive deionization (HCDI).
However, the scarcity of active sites and tendency to dissolve in
water-based solutions remain significant challenges. Herein, we
synthesized a polynaphthalenequinoneimine (PCON) polymer with stable
long-range ordered framework and rough three-dimensional floral surface
morphology, along with high-density active sites provided by C=O and C=N
functional groups, enabling efficient redox reactions and achieving a
high Na+ capture capability. The synthesized PCON polymer showcases
outstanding electroadsorption characteristics and notable structural
robustness, attaining an impressive specific capacitance of 500.45 F g-1
at 1 A g-1 and maintaining 86.1% of its original capacitance following
5000 charge-discharge cycles. Benefiting from the superior
pseudocapacitive properties of the PCON polymer, we developed an HCDI
system that not only exhibits exceptional salt removal capacity of 100.8
mg g-1 and a remarkable rapid average removal rate of 3.36 mg g-1 min−1,
but also maintains 97% of its initial desalination capacity after 50
cycles, thereby distinguishing itself with the comprehensive performance
that significantly surpasses reported organic deionization materials.
Prospectively, the synthesis paradigm of the double active-sites polymer
may be extrapolated to other organic electrodes, heralding new avenues
for the design of high-performance desalination systems.