CNT/copper Hexacyanoferrate: A Superior Faradic Electrode for Ammonium Ion Removal with Stable Performance and High Capacity

•The NH4+-rich copper hexacyanoferrate (N-CuHCF) and carbon nanotube (CNT) complex (CNT/N-CuHCF) was formed by a simple and fast co-precipitation-ion exchange method and used as ammonium-capturing electrodes.•The interconnected nanonetwork structure of CNT/N-CuHCF endows its larger surface area and abundant redox active sites for NH4+ adsorption.•The CNT/N-CuHCF demonstrates a superior SAC of 120.2 mg g−1, a low specific energy consumption, and remarkable cycling stability.