Three-dimensional macroporous graphene architectures as high performance electrodes for capacitive deionization

Abstract

In order to obtain excellent desalination behavior during the capacitive deionization (CDI) process, electrodes should provide efficient pathways for ion and electron transport. Here we open up a new opportunity to prepare high performance capacitive deionization (CDI) electrodes based on three-dimensional macroporous graphene architectures (3DMGA). The 3DMGA were fabricated by a simple template-directed method using polystyrene microspheres as sacrificial templates. The resulting 3DMGA exhibited a 3D interconnected structure with large specific surface area and high electric conductivity. The electrochemical behavior of the 3DMGA electrodes was analyzed by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. It was found that the 3DMGA showed superiority in electrosorption capacitance, low inner resistance, high reversibility and excellent stability. The power and energy density analysis further demonstrated that the 3DMGA electrode had a higher power output and lower energy consumption. According to the electrochemical measurements, the 3DMGA is quite desirable for high performance and low energy consumption capacitive deionization. The desalination capacity was evaluated by a batch mode electrosorptive experiment in a NaCl aqueous solution. An excellent desalination behavior of the 3DMGA was obtained due to the large accessible surface area, high electric conductivity and unique 3D interconnected macroporous structure. The 3DMGA was confirmed to be a promising material for CDI application.