Search

Micro-Supercapacitors (MSCs) are serving as potential candidates in the field of energy storage devices and applications. They have high capacitance and relatively small size and can be used as power storage for devices. The MSCs have many compartments and in recent years various forms of electrode materials are utilized in the MSCs. Graphene and its derivatives tagged with its unique properties are regarded as future flexible electronic and are widely explored electrode materials in many applications. Graphene can be used with other materials and forms hybrid structures to increase the capacitance of the devices. In this article, we briefly reviewed graphene and graphene derivatives used in the fabrication process of the MSC devices. The fabrication methods for the electrodes and the MSC devices are also evaluated. The various graphene-based MSCs and their capacitances are extensively summarized and compared in this review.

Ni-doped MoS2 was developed by facile solvothermal route. Ni2xMo1−xS2 with x = 0.05 emerged as a superior electrocatalyst with a current density value of − 405 mA cm−2 at an overpotential of − 200 mV vs. RHE. The catalyst efficiency index namely η10 was obtained to be − 133, − 68, − 70, − 80 and − 128 mV for x = 0, 0.05, 0.1, 0.15 and 0.2, respectively. This value indicates that at lower overpotential three compositions (x = 0.05, 0.1, 0.15) was equally efficient but with increase in overpotential x = 0.05 in Ni2xMo1−xS2, outstand the rest. The turn over frequency (H2/s) at η = − 100 mV vs. RHE for Ni2xMo1−xS2 with x = 0, 0.05, 0.1, 0.15 and 0.2 were calculated to be 0.3, 3.5, 2.0, 1.1 and 0.6, respectively. The prime reason for the enhanced performance is attributed to the increase in the number of active sites and electronic modulation due to the synergistic effect of MoS2, NiS and Ni3S4.

Biopolymers possess highly favorable properties for electrochemical biosensing such as their inherent biocompatibility, inexpensive nature, and strong interfacial adhesion. In this mini review, we will focus on chitosan and polydopamine, two of the most commonly used biopolymers, for electrochemical sensing applications. Chitosan is a polysaccharide that exhibits high chemical resistance, offers straightforward modification and cross-linking, and possesses antibacterial properties and mucoadhesion. Polydopamine has the benefit of universal adhesion, in addition to the ability to form self-assembled structures. We will demonstrate how the unique structural and electrochemical features of these biopolymers can be used in a range of electrochemical biosensing platforms.