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

An electrochemical synthesis which has been optimized to produce layered double hydroxides (LDHs) in- tercalated 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 re- sults 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 hy- brid 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.