Enabling Superior Sodium Capture for Efficient Water Desalination by a Tubular Polyaniline Decorated with Prussian Blue Nanocrystals

Abstract

The application of electrochemical energy storage materials to capacitive deionization (CDI), a low‐cost and energy‐efficient technology for brackish water desalination, has recently been proven effective in solving problems of traditional CDI electrodes, i.e., low desalination capacity and incompatibility in high salinity water. However, Faradaic electrode materials suffer from slow salt removal rate and short lifetime, which restrict their practical usage. Herein, a simple strategy is demonstrated for a novel tubular‐structured electrode, i.e., polyaniline (PANI)‐tube‐decorated with Prussian blue (PB) nanocrystals (PB/PANI composite). This composite successfully combines characteristics of two traditional Faradaic materials, and achieves high performance for CDI. Benefiting from unique structure and rationally designed composition, the obtained PB/PANI exhibits superior performance with a large desalination capacity (133.3 mg g−1 at 100 mA g−1), and ultrahigh salt‐removal rate (0.49 mg g−1 s−1 at 2 A g−1). The synergistic effect, interfacial enhancement, and desalination mechanism of PB/PANI are also revealed through in situ characterization and theoretical calculations. Particularly, a concept for recovery of the energy applied to CDI process is demonstrated. This work provides a facile strategy for design of PB‐based composites, which motivates the development of advanced materials toward high‐performance CDI applications.

Three-Dimensional Cobalt Hydroxide Hollow Cube/Vertical Nanosheets with High Desalination Capacity and Long-Term Performance Stability in Capacitive Deionization

“…Among these materials, metal oxides or hydroxides hold the advantages of easy preparation, facile morphological manipulation, element diversity, and promising desalination performance. Yet, charge-transfer materials usually show a tradeoff between high capacity and good stability [ 23 ]. Theoretically, higher capacity means that more ions are removed, which generally causes more obvious volume changes.…”

Carbon-incorporated Fe3O4 nanoflakes: high-performance faradaic materials for hybrid capacitive deionization and supercapacitors

“…67 To address this issue, hybrid CDI that uses a redox electrode to replace one of the two carbon electrodes has been developed. [68][69][70] Generally, TMOs are good candidates for electrode materials for HCDI, [71][72][73][74] and, recently, Fe 3 O 4 materials have received increasing interest in the HCDI field due to their high desalination performance and great abundance. 75 In this section, we plan to evaluate the potential of our 2D-Fe 3 O 4 /C for HCDI applications.…”

Metal–organic framework-based materials: advances, exploits, and challenges in promoting post Li-ion battery technologies

“…This work demonstrates a facile approach for designing PB-based composites, thus motivating the progress of advanced materials for high-performance capacitive deionization applications. 152…”