Unique bi-directional coordinative interaction of 2D inorganic nanosheet with Prussian blue nanocrystal for optimizing its functionality

An interfacial electronic coupling, a crucial factor in optimizing the functionality of hybrid material, can be enhanced by unique bi-directional coordinative bonding of 2D metal oxide nanosheet with Prussian blue (PB) nanocrystal. A strong mutual interfacial bonding between monolayered 2D MnO₂ nanosheet and PB nanocrystal can be achieved by remarkable coordination abilities of the surface-exposed oxide ions of MnO₂ and the cyanide ligand of PB. Due to the enhanced interfacial electronic coupling, the PB−layered MnO₂ nanohybrid shows excellent supercapacitor electrode performance with huge specific capacitance of 623 F g⁻¹ at 5 mV s⁻¹, i.e. the largest value among ever-reported PB-based electrodes, which is much superior to those of the pristine PB and PB−graphene homologue. In-situ micro-Raman analysis highlights the enhancement of the Faradaic redox process of PB lattice by strong interfacial coupling with MnO₂ nanosheet. The present study underscores that the introduction of bi-directional coordinative bonding with 2D inorganic nanosheets allows to provide novel synthetic strategy to explore highly efficient energy-functional coordination-compound-based materials.