Preparation of core-shell NiMnB/rGO composite electrodes and their application in hybrid supercapacitors.

The rapid advancement of science and technology has led to the development of electronic devices that require higher energy storage capacities. Because of their greater energy as well as power density capabilities, hybrid supercapacitors offer an answer to the problems that result from the limitations of both supercapacitors and batteries when it comes to power densities and energy density. Borate ion-functionalized nickel manganese hydroxide nanoparticles (denoted as NiMnB) were prepared by a simple chemical reduction method, and novel complexes were obtained by growing NiMnB with a core-shell structure on reduced graphene oxide (rGO). The NiMnB inner core facilitates electron transport, while the borate/metal borate shell layer on the outer layer aids in OH- absorption. Additionally, rGO integrates the dispersed nanoparticles, resulting in a comprehensive conductive system. This design optimizes the electrochemical performance of NiMn-based electrodes. The specific capacitance of the NiMnB/rGO-16 electrode was 916 F g−1 when tested at a current density of 1 A g−1. NiMnB/rGO-16 was used as the positive electrode and activated carbon (AC) as the negative electrode assembled the hybrid supercapacitor. It showed strong cycling stability and an energy density of 50.2 Wh kg−1. [Display omitted] • Electrode materials with core-shell morphology (NiMnB/rGO) were successfully prepared by chemical reduction method. • NiMnB/rGO-16 electrode shows high specific capacitance of 916 Fg−1 at a current density of 1 A g−1. • The NiMnB/rGO-16//AC device exhibits a high energy density of 800.4 Wkg−1,50.2 Wh kg−1. • NiMnB/rGO-16//AC maintains 86.3 % of initial capacitance after 8000 cycles at 5 A g−1. [ABSTRACT FROM AUTHOR]