Designed Synthesis Of Prussian Blue Analogue Materials And It's Electrochemical Applications

Prussian blue?PB?and prussian blue analogue?PBA?,as well as their composites and derivatives have received great attention in recent years because of its wide applications including adsorption&separation,sensing,catalysis,drug delivery and cancer therapy.Among of them,it is our most interest that they can applied as electrochemical energy storage devices,such as supercapacitors.Prussian blue materials show a lot of advantages for these applications.?1?Three-dimensional frameworks provide sufficient ion transport channels.?2?Successful tuning the metal composition can provide rich active sites for electrochemical reactions.?3?The structure of PBAs built from various metal ions and organic linkers as precursors provide more choices for the formation of new functional materials.Based on these considerations,we focus on the successful fabrication of new functional materials based on PB and PBAs,and their electrochemical application for supercapacitors.The related mechanism was discussed in detail.They are divided into two works,as follows.?1?Graphene@prussian blue?G@PB?nanocomposite sheets have been successfully fabricated via in-situ one-step hydrothermal procedure.Such simple method realized the efficient syntheses of graphene sheets fully covered by PB nanoparticles.A series of G@PB nanocomposite sheets with different graphene content were prepared,labeled as G@PB-1,G@PB-5,and G@PB-10,respectively.Among of them,G@PB-5 shows the highest capacitance of 388.09 F g^-1at a current density of 1 A g^-1.In addition,its rate capability was great improved.Long-term stability of97.2%retention over 5000 cycles can be observed.Its coulombic efficiency is nearly 100%.Then,asymmetric supercapacitor was assembed,in which the obtained G@PB-5 as the positive electrode and activated carbon?AC?as negative electrode.The AC cell displays a wide reversible operating voltage of 2.0 V.In conclusion,G@PB-5 nanocomposite sheets can be considered as a promising energy storage electrode due to its high electrochemical performances.?2?A core-shell structure of CoPBA@Ni?OH?₂ was successfully obtained,in which CoPBA was uniformly deposited on the surface of two-dimensional Ni?OH?₂ sheets.The core-shell structure of CoPBA@Ni?OH?₂ as template was converted into porous CoS₂@NiS₂ composite.It as electrode has shown high specific capacitance value of 1731.2 F g^-11 at a current density of 1 A g^-1,and excellent rate capability and cycle performance.Such high performance can be attributed to several factors,as follows.?1?Target CoS₂ with higher conductivity than NiS₂ improved its electrochemical properties.?2?The abundant nitrogen-doped carbon network reduces the resistance of the materials.?3?The cubic morphology of PB?PBA?effectively prevents the agglomeration of electroactive NiS₂.?4?target composites with mesoporous structure increase the mass diffusion path and decrease the structural damage caused by volume expansion during the charge and discharge cycle.In summary,this paper provides the summary about related PB and PBAs materials.Based on the review,a series of new functional materials were successfully fabricated.They exhibited enhanced electrochemical performance.The synthesis procecdures were described in detail.Their properties were systematically discussed based on the relatonship between microstructure and perperties.In one word,the paper provides reliable synthetic strategies and verified effection.Based on these results,prussian blue materials can be considered as great supecapacitors.