Preparation And Electrochemical Performance Of Phytate-base Porous Polymer

In recent years,due to its non-toxicity,availability,wide availability,and variety,bio-derived materials connected by metal ions and biological precursors?such as polyphenols,porphyrins,polybasic acids,etc.?have gradually become attractive functional materials.Phytic acid,also named as inositol hexakisphosphate,is an interesting material because it is one of the compounds with the highest P/C ratio and can be obtained in legumes and plant extracts.Phytic acid contains a large number of phosphoric acid groups,which has a strong affinity to metal ions,so it is capable of forming various metal phosphonates after complexing with specific metal ions.Metal phosphonates is composed of organic ligand and inorganic metal ions,where always generates a certain coupling effect,leading to the unique physicochemical properties.More importantly,through the careful design of metal ions or organic ligands,a rich and versatile organic-inorganic hybrid framework can be prepared,which provides a good opportunity for their applications in the fields of energy storage,catalysis,environment and biomedicine.However,previous studies have shown that most of the metal phosphates and metal phosphonates present dense layered structures with small specific surface area,which hinder their application in the fields of catalysis,adsorption and energy storage.The introduction of hierarchical porous structure into the material by self-assembly is promising to greatly expands its application in different fields.In particular,porous structures can provide materials with more exposed active sites and specific ion transport channels,making it an attractive candidate as an advanced electrode material for energy storage and other fields.Therefore,this paper focuses on the development of novel strategies for the synthesis and structure regulation of phytate-based porous polymers,and further explores their potential applications in the field of electrochemistry.1.Preparation of hollow mesoporous ferric phytate nanospheres and the investigation of their sodium ion storage properties.Based on solution self-assembly,a coordination polymerization-driven micelle self-assembly strategy has been developed.In this method,two kinds of micelle with different properties were employed to form supramolecular template,and after the addition of phytic acid and ferric ions,the organic polymer of ferric phytate with controllable structure was prepared successfully.Here,aliphatic fluorosurfactants?PFOA?and polystyrene-b-poly?ethylene oxide?block copolymers?PS-b-PEO?are separately assembled to form two different discrete micelles.Driven by the forces of coordination polymerization of ferric phytic precursors,PFOA first evolved into hollow vesicles with carboxyl groups on the surface,and then a large number of smaller spherical micelles assembled by PS-b-PEO were attracted to the surface due to hydrogen bonding.Finally,the co-assembly of the two micelles further confined the growth of the precursor.We successfully controlled the morphology and microstructure of ferric phytate for the first time by this scheme.The obtained ferric phytate nanospheres feature hollow architecture,ordered mesoporous?¹2 nm?,a high surface area(401 m² g^-1),and large pore volume(0.53 cm³ g^-1).Moreover,as a anode material,the bio-derivative polymer nanospheres delivers an excellent reversible capacity of 540 mAh g^-1 at an current density of50 mA g^-1,remarkable rate capability,and cycling stability for the storage of sodium-ion.2.Construction of ultrathin metal phosphate nanomeshes and the investigation of their lithium ion storage properties.Similarly,we replaced the aliphatic surfactants mentioned above with longer carbon chain,which called perfluorooctadecanoic acid.It was also assembled with spherical micelles formed from polystyrene-b-polyethylene oxide?PS-b-PEO?to obtain a supramolecular assembly.Then,ultrathin mesoporous ferric phytate nanomeshes can be easily obtained by templating the supramolecular co-assembly of amphiphilic block copolymer and aliphatic fluorosurfactant.In addition,by changing different phosphorus sources,phosphonate mesoporous nanomeshes with different ligands and the same microstructure were successfully obtained,which confirmed that this method is a universal method.More importantly,the resultant mesoporous ferric phytate nanomeshes can directly serve as a novel reactive self-template for the in-situ fabrication of other types of nanomeshes,e.g.mesoporous sulfur-doped metal phosphonate nanomesh materials.The 2D mesoporous ferric phytate nanomeshes obtained by this method has ultra-thin thickness?⁹ nm?,uniform pore size?¹6 nm?and high specific surface area(29 m ² g^–1).As a lithium ion electrode material,it has a high reversible capacity of 566 mAh g^-1at 50 mA g^-1,accompanied by good rate performance and cycle stability.