Heteroatom Modification of Heterostructured CuS/Mn3O4with Rich Defects for Solid-State Supercapacitors

Heterostructure construction and heteroatom mod-ification are considered as effective approaches to modulate theelectronic structure and boost the energy storage activity ofelectrode materials. Herein, oxygen-modified CuS/Mn3O4(O-CuS/Mn3O4) heterogeneous nanoflakes with abundant defects arefabricated by solid-state grinding followed by NaBH4treatment(NBHT) at room temperature using MnCu Prussian blue analogue(MnCu-PBA) as the precursor. During the NBHT, a portion of thesulfur atoms in CuS is removed, and the remaining sites in thelattice are occupied by oxygen in the water, resulting in an oxygenmodification. Experimental results and theoretical calculationsconfirm that heterojunction, defect, and oxygen modification notonly greatly facilitate the adsorption of OH-on the surface of theelectrode material but also endow improved electrical conductivity, wettability, specific surface area, and active sites. Benefiting fromthese advantages, O-CuS/Mn3O4exhibits an excellent specific capacitance of 1307 F g-1at 1 A g-1. Moreover, the solid-stateasymmetric supercapacitor with O-CuS/Mn3O4and MnO2(O-CuS/Mn3O4//MnO2) shows an outstanding energy density of 34.4Wh kg-1at 800.1 Wmiddotkg-1and cyclic stability with 85.7% capacitance retention after 5000 cycles at 6 A g-1. Our work highlights theintegration of heterojunction and oxygen modification to fabricate and optimize the energy storage electrode materials.

Automated summary

Heterostructure construction and heteroatom modification were used to fabricate and optimize oxygen-modified CuS/Mn3O4 heterogeneous nanoflakes with abundant defects which showed enhanced energy storage performance.