Electrosynthesis of Ni/Al layered double hydroxide and reduced graphene oxide composites for the development of hybrid capacitors

Abstract

An electrochemical synthesis which has been optimized to produce layered double hydroxides (LDHs) intercalated with carbon nanomaterials is proposed for the first time. It is based on a one-step procedure which contemporaneously allows for the Ni/Al-LDH synthesis, the reduction of graphene oxide (ERGO) and its intercalation inside the structure. The LDH/ERGO composites were thoroughly characterized by a comprehensive multi-techniques approach in order to verify their structure and morphology. The results confirmed that a LDH structure was observed only if the GO concentration was not higher than 0.2 mg/mL. All the characterizations led to propose a theorization of the synthetic and growth mechanisms of the composites. The best performing material was employed as cathode for the development of a hybrid supercapacitor. The device had a discharge specific capacitance of 880 F g−1. The promising results obtained in this work embrace the necessity of development of low environmental impact systems; in fact, the proposed hybrid supercapacitor is binder-free, safe, composed of earth abundant elements and able to work in aqueous electrolyte.