Cross-linked NiCo2O4 and MnFe2O4 nanosheets wrapped Lentinula edodes-derived carbon as an efficient electrode material

Abstract

Efficient and environmentally friendly energy storage systems are urgently required because of severe environmental problems and high energy demands. Compared to traditional devices used to store energy, supercapacitors have received extensive attention from researchers referring to their excellent performance. Because of their unique characteristics, carbon generated from biomass and transition metal oxides are commonly employed in supercapacitors and used to prepare effective electrode materials. However, their electrochemical behavior has several limitations. In this study, two types of nanosheets, NiCo2O4 and MnFe2O4 were sprouted on the surface of Lentinula edodes-derived carbon by a simple strategy availing two-step hydrothermal to prepare the composite electrode material with two kinds of nanosheets intercalating and crosslinking on a carbon core (LDC@NiCo2O4/MnFe2O4). In this process, the carbon core, as a stamen, was uniformly covered with nanoflake petals. Under the conditions of 1 A g−1, LDC@NiCo2O4/MnFe2O4 represented a specific capacitance of 1017 F g−1, proving that LDC@NiCo2O4/MnFe2O4 has a huge prospect application in supercapacitors. Futhermore, we manufactured an asymmetric supercapacitor (ASC) including LDC@NiCo2O4/MnFe2O4 as the positive electrode and activated carbon which was used as a negative electrode. At a power density of 725 W kg−1, the device we fabricated reached an energy density of 24.49 Wh kg−1. Thus, the capacitance retention rate of the ASC device was still 82.3% compared to the initial capacitance of the device after 10,000 cycles. This study provides a comprehensive reference aimed at improving the utilization efficiency of transition metal compound materials in electrochemical energy storage devices.