Achieving Enhanced Capacitive Deionization by Interfacial Coupling in PEDOT Reinforced Cobalt Hexacyanoferrate Nanoflake Arrays

Abstract

Capacitive deionization (CDI) as a novel energy and cost‐efficient water treatment technology has attracted increasing attention. The recent development of various faradaic electrode materials has greatly enhanced the performance of CDI as compared with traditional carbon electrodes. Prussian blue (PB) has emerged as a promising CDI electrode material due to its open framework for the rapid intercalation/de‐intercalation of sodium ions. However, the desalination efficiency, and durability of previously reported PB‐based materials are still unsatisfactory. Herein, a self‐template strategy is employed to prepare a Poly(3,4‐ethylenedioxythiophene) (PEDOT) reinforced cobalt hexacyanoferrate nanoflakes anchored on carbon cloth (denoted as CoHCF@PEDOT). With the high conductivity and structural stability achieved by coupling with a thin PEDOT layer, the as‐prepared CoHCF@PEDOT electrode exhibits a high capacity of 126.7 mAh g−1 at 125 mA g−1. The fabricated hybrid CDI cell delivers a high desalination capacity of 146.2 mg g−1 at 100 mA g−1, and good cycling stability. This strategy provides an efficient method for the design of high‐performance faradaic electrode materials in CDI applications.