Hierarchical NiMn Double Layered/Graphene with Excellent Energy Density for Highly Capacitive Supercapacitors

Abstract

In the present article, highly capacitive NiMn-LDHs/GO composite of electrode material has been the synthesized for supercapacitor energy storage. Various analytical techniques (particularly X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), and scanning electron microscope (SEM)) have been employed to characterize the as-synthesized NiMn-LDHs/GO. The Microscopic images obtained using HRTEM analysis clearly reveal the formation of lattice fringe pattern (lattice spacing as ~ 0.22 nm) for GO, whereas SEM images shows highly porous nature. The super-capacitive performance of the as-synthesized electrode material have been accessed through an electrochemical work station comprising of a 3-electrode system. The working electrode made up of NiMn-LDHs/GO (Active material) on Ni foil (working electrode) with the help of PVDF (binder), has shown specific capacitance of 1964 F g−1 at current density of 1 A g−1 with Galvanostatic charging/discharging (GCD) technique. It has also shown remarkable cyclic stability with a capacitance retention of 98% after 2000 cycles. The high-power density (401 W/kg) and energy density (17.78 Wh/kg) signify the high-level electrochemical supercapacitor behaviour in charge storage applications.

Overview of Supercapacitors: A Comprehensive Review

“…These polymers are conductive and can undergo redox reactions, providing high capacitance and flexibility. However, they may suffer from stability issues over long-term cycling [17].…”

“…Combining transition metal oxides with conducting polymers or carbon materials can enhance the overall performance of pseudocapacitors. These composites leverage the high capacitance of metal oxides and the conductivity and stability of polymers or carbon materials [18].…”

A Comprehensive Review on Various Techniques Used for Synthesizing Graphene Quantum Dots

“…The hydrothermal method offers a straightforward and expeditious approach to fabricate graphene quantum dots (GQDs) [50,51]. By employing various macromolecular or small molecular substances as starting materials, GQDs are ultimately obtained through high-temperature and highpressure conditions [52].…”

“…The carbonization pyrolysis method, also known as small-molecule carbonization, has emerged as a straightforward approach owing to ongoing research on GQDs [58,59]. The fundamental mechanism involves heating the small-molecule precursor carbon source material above its melting point using specialized instruments.…”

Advances in the Synthesis of Graphene: A Comprehensive Review

“…In electronics, graphene-based transistors, sensors, and interconnects offer the potential for faster, more efficient devices with reduced energy consumption [6,7]. In energy storage and conversion, graphene-based materials show promise for high-capacity batteries, supercapacitors, and fuel cells due to their large surface area and fast charge transport properties [7,8]. In energy storage and conversion, graphene-based materials show promise for high-capacity batteries, supercapacitors, and fuel cells due to their large surface area and fast charge transport properties [7,9].…”