Engineering a Novel AgMn2O4@Na0.55Mn2O4 Nanosheet toward High-Performance Electrochemical Capacitors

Abstract

Manganese oxides, as a type of two-dimensional (2D) material with high specific area and low cost, are considered promising energy storage materials. Here, we report novel AgMn2O4/Na0.55Mn2O4 nanosheets created by a popular liquid precipitation method with different AgNO3 contents, and their corresponding physical and electrochemical characterizations are performed. The results show that the ultra-thin Na0.55Mn2O4 nanosheets were combined with the AgMn2O4 nanoparticles and an enhancement in their specific capacity was observed compared to the pristine sheets. This electrode material displays a peak specific capacitance of 335.94 F g−1 at 1 A g−1. Using an asymmetric supercapacitor (ASC) assembled using a positive electrode made of AgMn2O4/Na0.55Mn2O4 nanosheets and a reduced graphene oxide (rGO) negative electrode, a high energy density of 65.5 Wh kg−1 was achieved for a power density of 775 W kg−1. The ASC showed good cycling stability with a capacitance value maintained at 90.2% after 10000 charge/discharge cycles. The excellent electrochemical performance of the device was ascribed to the heterostructures and the open space formed by the interconnected manganese oxide nanosheets, which resulted in a rapid and reversible faraday reaction in the interface and further enhanced its electrochemical kinetics.

High-Performance 3D Nanostructured Silver Electrode for Micro-Supercapacitor Application

“…Among these alternatives, silver generates high interest as it exhibits an electrochemical behavior close to that of ruthenium oxide, is cheaper than ruthenium oxide, and is more environmentally sustainable. , Also, silver in its different oxidation states (AgO, Ag 2 O, and Ag 2 O 2 ) is more conductive than other transition-metal oxides investigated for pseudocapacitor applications and has more ability to change and adopt different oxidation states (+1, +2), providing the energy storage ability. Furthermore, from the electrochemical perspective, silver is very reactive and forms different oxide phases such as AgO, Ag 3 O 4 , Ag 4 O 3 , Ag 2 O 3 , and Ag 2 O, where Ag 2 O is the most stable among them. − In addition, silver has been used in previous studies as a component of electrodes; also, silver nanowires are commonly used in flexible and wearable electronic devices. Nanocomposites of silver nanoparticles with graphene, carbon nanotubes, metal oxides, or conducting polymers have been tested for their use in several energy storage applications.…”