P Hosp Hate-Based Electrode Materials For Aqueous Ion Batteries: Preparation,Characterization,and Assembly

Nasicon–type pHospHate materials has received increasing attention in recent years due to their superior characteristics,such as stable three-dimensional framework which are beneficial for ion transport,low cost,rich raw material sources,environment friendly and excellent thermal stability.In this paper,mesoporous ATi₂?PO₄?₃/C?A=Li,Na?nanocrystals have been prepared by annealing the precursor obtained through a simple room-temperature co-precipitation method.In the coprecipitation procedure,tetrabutyl titanate,lithium hydroxide?sodium hydroxide?,and pHytic acid were mixed in Ethanol and butanol mixture solution which inhibiting the hydrolysis rate of titanate to produce the precursor.The mesoporous ATi₂?PO₄?₃/C?A=Li,Na?nanocrystals were characterized with XRD,Raman,SEM,TEM,TG/DSC,XPS and BET techniques,and tested the electrochemical performance of sample in aqueous electrolytes.The results showed that:?1?The samples of ATi₂?PO₄?₃/C possess the following characteristics:good crystalline,high purity and relatively larger specific surface area?SBET?,has the rich of the structure of the mesoporous.?2?Electrochemical properties were measured,using 1 M Li₂SO₄ as the electrolyte,the Cd of Li Ti₂?PO₄?₃/C is calculated separately to be 84.4,73.9,68.9,64.3,and 55.9 mAh g^-1 at 0.1,0.2,0.5,1,and 2 A g^-1,and the coulombic efficiency of LiTi₂?PO₄?₃/C approximates to 97%.?3?The electrochemical performance of the pouch cells in configuration of LTP/C???|Li₂SO₄|LiMn2O4?+?were measured,the specific discharge capacity of the cell?Ccell?is 28.1 mAh g^-1 at 0.1 A g^-1.After 1000 cycles,the Ccell retains 20.1 mAh g^-1,offering a capacity retention of 71.5%.?4?The electrochemical properties of NaTi₂?PO₄?₃/C were measured,using 1 M Na₂SO₄ as the electrolyte,We explore the influence of the O2 and different pH of electrolyte,and the results showed that the Cd of NaTi₂?PO₄?₃/C is better using 1 M Na₂SO₄?pH=9 and oxygen-free?as the electrolyte.?5?We study the effect of different calcination temperature on the electrochemical properties,the results show that the electrochemical properties of samples calcined under 750 ? is better than calcined under 700 ? and 800 ?.?6?The Cd of Na Ti₂?PO₄?₃/C calcined under 750 ? is calculated separately to be 115.6,112.3,109.0,104.2,and 93.7 mAh g^-1 at 0.1,0.2,0.5,1,and 2 A g^-1.After 1000 cycles at 1 A g^-1,the Cd retains 33.33 mAh g^-1,offering a capacity retention of 33%.