Encapsulating Mn-Fe prussian blue analog nanocuboids into the graphene framework towards fast and durable sodium storage

The exploration of high-performance sodium-ion hosts is an important issue in the field of advanced energy storage and conversions. Herein, MnFe PBA/rGO composite was prepared by simple coprecipitation and in situ synthesis, and realized the fast kinetics and superior stability for sodium storage. The rGO nanosheets were introduced as the framework to encapsulate the MnFe PBA nanocuboids with uniform particle size and well-defined configuration to further enhance their electrical conductivity and electrochemical properties. The prepared MnFe PBA/rGO composite exhibits superior charge/discharge properties than the pristine MnFe PBA nanocuboids, which show a capacity enhancement of over 30%. In addition, the PBA/rGO composite exhibits excellent cycling stability, which retains 80% of the capacity after 1000 cycles at a high rate of 1 A/g. The electrochemical impedance spectroscopy (EIS) results further demonstrate the low resistance, high durability, and ultrahigh stability of the MnFe PBA/rGO composite during high-rate long-term cycling. Therefore, this work not only provides a high-performance sodium host but also gives a new clue to the design and construction of highly efficient electrode materials for advanced electrochemical systems.