Novel design of Mn3O4-doped carbon xerogel microspheres and their electrochemical performance as a high energy density hybrid supercapacitor

Abstract

The improvement of supercapacitor electrodes with substantial energy density is a pivotal necessity in the global transition toward sustainable energy sources. However, the synthesis processes commonly used for producing supercapacitor electrodes based on metal oxide-doped carbon xerogels are associated with extended durations and demonstrate relatively low energy and diminished power density, hindering their practical applicability and large-scale manufacturing. This study aims to fabricate manganese oxide-doped carbon xerogel-based electrodes in a significantly reduced timeframe by utilizing the rapid preparation of carbon xerogel under strong acidic conditions. Additionally, the impact of varying manganese precursor contributions (0.5 %, 1 %, 2 %, 3 %, 5 %, and 10 %) on the morphology and electrochemical characteristics of the samples was investigated. The 1 % manganese (CX 1 %Mn) sample exhibited the highest BET surface area of 953 m²⋅g^-1, resulting in an enhanced capacitive behavior with a specific capacitance of 595 F⋅g ⁻¹ at 0.5 A⋅g⁻¹ and a capacitance retention of 95 % at a current density of 2 A⋅g ⁻¹ after 5000 repetitive cycles. Moreover, a remarkable energy density of 56.75 Wh·kg⁻¹ and a power density of 22.9 kW·kg⁻¹ were attained, accompanied by a significant drop in equivalent series resistance to 0.72 Ω. The Carbon Xerogel prepared with 0.1 M HCl and 1 %Mn (CX1 %Mn) displays enhanced performance due to its excellent morphological features, including high BET surface area, pore volume, and pore diameter. This study presents a straightforward method to prepare manganese oxide-doped carbon xerogel-based supercapacitor electrodes, improving efficiency and upgraded stability. Furthermore, it introduces new opportunities to investigate the effects of various metal oxides based on this novel approach.