The Structure Design And Performance Research Of High Specific Energy Water-based Metal Ion Battery Cathode Materials

Rechargeable aqueous metal ions batteries?RAMB?have the advantages of low cost,high safety,environmental friendliness and high ion mobility,which make it great potential to be applied in the large scale energy storage.But the operating voltage of RAMB is relatively low and the cycling performance and coulombic efficiency display not very good.Therefore,it is urgent to find suitable electrode materials and aqueous electrolyte to construct new-type RAMB with high performance.In this work,a new type of aqueous sodium ion battery and zinc ion battery are constructed based on the selection of suitable cathode materials and a new type of aqueous electrolyte.It is hoped that the battery's discharge capacity and energy density can be improved while improving the cycle stability of the battery.Firstly,a high-quality and low-defect Fe₄[Fe?CN?₆]₃?HQ-FeHCF?nanomaterial was successfully synthesized by a modified hydrothermal method with sodium ferrocyanide as a single iron source.The structural morphology and electrochemical properties of Fe₄[Fe?CN?₆]₃ were studied.A full battery based on Fe₄[Fe?CN?₆]₃ as a cathode,NaTi₂?PO₄?₃ as an anode and NaClO4-H2O-PEG?Polyethylene glycol?as the electrolyteis is well established.It has discharge capacities of 117 mAh·g^-1 at 1C rate in the electrolyte of NaClO₄-H₂O-PEG.It can deliver a specific energy density of 126Wh·kg^-1?based on the active electrode materials?with a voltage output of 1.9 V that is superior to many other rechargeable aqueous sodium-ion batteries.In addition,92%of its initial discharge capacity is retained after 140 charge/discharge cycles at a rate of 5C and its coulombic efficiency is close to 100%.Secondly,LiVOPO₄ nanocubes were synthesized by sol-gel method,and the LiVOPO₄ was modified by chemical vapor deposition.The structural morphology and electrochemical properties of LiVOPO₄ were studied.A full battery based on LiVOPO₄as a cathode,Zn as an anode and Zn?ClO4?2-H2O-PEG as the electrolyteis is well established.It has discharge capacities of 136 mAh·g^-1 at 0.2C rate in the electrolyte of Zn?ClO4?2-H2O-PEG.It can deliver a specific energy density of 190 Wh·kg^-1?based on the active electrode materials?with an average voltage output of 1.9 V that is superior to many other rechargeable aqueous Zinc-ion batteries.In addition,91%of its initial discharge capacity is retained after 300 charge/discharge cycles at a rate of 5C and its coulombic efficiency is close to 100%.