Synthesis Of Prussian Blue Analogues And Their Application In Aqueous Non-metallic Ion Batteries

Aqueous non-metallic ion batteries are considered as potential energy storage solutions due to their fast kinetics,low cost,stable nature and high safety.Electrode materials suitable for non-metallic ion batteries are still under continuous research.Prussian blue analogs（PBAs）have received a lot of attention from scientists because of their open and stable three-dimensional skeleton structure,low fabrication cost,and promising applicability for large-scale energy storage applications.However,PBAs materials still have some problems,such as low specific capacity,poor electronic conductivity,and irreversible phase change during deep charging/discharging process.Therefore,in order to solve the above problems to develop electrode materials with excellent multiplicative performance and stable cycling performance,this thesis adopts the composite conducting polymer PANI and conducts the substitutable modulation of active metal ions to enhance the electrochemical performance for PBAs materials,as follows:（1）Na_0.73Ni[Fe（CN）₆]_0.88 was used as raw material for in situ polymerization of PANI by covalent bonding assisted engineering application,and the synthesized PANI/Na_0.73Ni[Fe（CN）₆]_0.88 hybrid（PNFF）inherited the advantages of high conductivity of PANI and stability of PBAs.The effect of PANI content on the electrochemical performance of PNFF was investigated.When used as the cathode material for aqueous ammonium ion batteries,PNFF-60 provides a reversible capacity of 92.5 m Ah g^-1 at 100 m A g^-1.In addition,the energy storage mechanism during NH₄⁺deembedding/embedding of PNFF-60 was comprehensively investigated by In-situ Raman and Ex-situ XPS/FTIR analysis.Thanks to the synergistic effect of PBAs and PANI,the capacity retention of PNFF-60 electrode was95.2%after 1000 cycles.（2）Vanadium hexacyanoferrate Prussian blue analog（VOHCF）nanoparticles were prepared by hydrothermal method by taking full advantage of VO₂⁺/VO²⁺and[Fe（CN）₆]^4-/[Fe（CN）₆]^3-redox activity.Due to the introduction of V=O bonds,the prepared VOHCF cathode material achieves a high reversible capacity capacity of 103.8 m Ah g^-1 at a current density of 0.1 A g^-1,and excellent multiplicative performance is obtained due to the capacity contribution of ion diffusion and surface pseudocapacitance.In addition,the energy storage mechanism in the H⁺deembedding/embedding process of VOHCF was investigated in depth by In-situ Raman and Ex-situ XPS/FTIR analysis,and it was demonstrated that both V and Fe in the cathode of VOHCF are involved in the redox reaction,which leads to its excellent electrochemical performance.（3）Finally,the prepared PNFF-60 cathode and VOHCF cathode were coupled with polyimide@MXene（PI@MXene）anode and HATN anode,respectively,to assemble aqueous ammonium-ion battery and aqueous proton battery devices.The PNFF-60//PI@MXene battery provides a charge specific capacity of 52.5 m Ah g^-1 at 1000 m A g^-1 with a capacity retention rate of 83%（200 cycles）,demonstrating long-lasting cycle stability.In addition,the VOHCF//HATN battery exhibits excellent multiplicative performance with a capacity of 42.8m Ah g^-1 at 4 A g^-1.This work increases the understanding of constructing aqueous nonmetallic ion energy storage devices based on PBAs.