Recent advancements of NiCo LDH and graphene based nanohybrids for supercapacitor application

Supercapacitors epitomize a breakthrough technology to store electrical energy for various applications including space, electronics, automobiles, and military. Especially the electrode materials play a vital role in supercapacitors; thus, many researchers have been centered on developing novel high performance electrode materials. The advent of layered double hydroxides (LDHs) based nanomaterials has spurred enormous research attention owing to their charming electrochemical properties. Among all NiCo LDH has gathered considerable research attention owing to its outstanding advantages such as cost effective, ease of synthesis, high redox activity, and high theoretical capacity. However, it lacks with severe capacity deterioration due to the instability and low-rate capability. A combination of NiCo LDHs with carbonaceous materials has given stupendous improvement to the performance of supercapacitors in terms of specific energy, specific capacitance, and specific power. Composites with graphene usually display superior performances than the pristine due to the combination of both EDLC (electricdouble layer capacitance) and pseudocapacitive mechanism by providing improved surface area, conductivity, enhanced hydrophilicity. In this review, the recent advances on the composites of NiCo LDH and graphene are explored for supercapacitor application. Typically, we have focused on the reports related to the composites containing graphene (or reduced graphene oxide) with NiCo LDH primarily discussing on their major synthesis routes, physicochemical characterization, and electrochemical performances. Finally, the concluding remark along with future perspective is also presented.