Nitrogen-doped carbon nanorods with excellent capacitive deionization ability

Nitrogen-doped carbon nanorods (NCNRs) were prepared from naturally based nanocrystalline cellulose through simple freeze drying and subsequent thermal treatment under an ammonia atmosphere at different temperatures. The morphology, structure and electrochemical performance of the NCNRs were characterized using scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption, X-ray photoelectron spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy, and their electrosorption performance in NaCl solution was studied. The results show that NCNRs treated at 1000 °C exhibit an extremely high electrosorption capacity of 17.62 mg g^-1 when the initial NaCl concentration is 500 mg l^-1, which shows great improvement compared with their undoped counterparts. The nitrogen doping proved to be a very effective method for improving the electrosorption performance, and the NCNRs should be very promising candidates as electrode materials for CDI applications.