Preparation And Characterization Of Glassy Fast Ion Conductor

1.5Li2O-P2O5-xTiO2glassy fast ionic conductor is synthesized using solid statemethod. After crystallization, forming glass fiber, doping Al2O3and carbon,1.5Li2O-P2O5-xTiO2glass turns into1.5Li2O-P2O5-xTiO2glass-ceramic,1.5Li2O-P2O5-0.5TiO2-yAl2O3glass and glass-ceramic,1.5Li2O-0.4TiO2-P2O5/C glassand1.5Li2O-P2O5-xTiO2glass fiber fast ionic conductor, respectively. Theelectrochemical properties of these materials are tested for studying the effect of abovefactors on electrochemical properties.As x increases, the network structure of1.5Li2O-P2O5-xTiO2glass is getting tightand conductivity is getting higher at room temperature. The highest conductivity is8.72×10-7S/cm. After crystallization, the appearance of LiTi2(PO4)3crystals enhancesthe conductivity of glass. When x=0.7, the conductivity reach the highest value at roomtemperature, that is8.72×10-7S/cm. The doping of Al2O3decreases the conductivity ofglass. After crystallization, as the increase of the content of Al2O3the conductivityincrease at first and decrease later. The highest conductivity at room temperature is1.55×10-6S/cm. The doping of carbon into glass1.5Li2O-P2O5-0.4TiO2using glucoseand acetylene black as carbon source both increase its conductivity. Conductivity isincrease as the increase of carbon content in glass. The highest conductivity is4.73×10-7S/cm at room temperature and it has been increased by40.36%. The impact of twocarbon source for the conductivity of glass is similar.As cathode materials of lithium battery, the charge-discharge property of1.5Li2O-P2O5-xTiO2glass is worse and the specific discharge capacity is lower than1mAh g-1at the current density of25mA g-1. As anode materials for lithium ionsecondary battery, the charge-discharge property of1.5Li2O-P2O5-xTiO2glass isobviously better than cathode materials. The specific discharge capacity increases as thex increase. When x=0.5the charge-discharge property of glass is best and the currentdensity is33.3mAh g-1,3.63%capacity loss of the initial value at the20th cycle at thecurrent density of25mA g-1. After crystallization, discharge capacity of glass more thantripled, because of the change of glass network and the appearance of LiTi2(PO4)3crystals in glass. The highest discharge capacity of glass-ceramic is113.5mAh g-1whenx=0.5and24.2%capacity loss of the initial value at the20th cycle at the current densityof25mA g-1. The doping of Al2O3enhances the charge-discharge property of glass sharply. When y=0.2the charge-discharge property of1.5Li2O-P2O5-0.5TiO2-yAl2O3glass is best, with78mAh g-1discharge capacity and1.27%capacity loss of the initialvalue at the20th cycle at the current density of25mA g-1. When y=0.15, thecharge-discharge property of1.5Li2O-P2O5-0.5TiO2-yAl2O3glass-ceramic is best, with80.4mAh g-1discharge capacity and2.98%capacity loss of the initial value at the20thcycle at the current density of25mA g-1. The1.5Li2O-P2O5-xTiO2glass fiber has layerstructure in the micron scale, the network structure of whose become tight from insideto surfice. The electrochemical property of glass fiber is enhanced because of it’sspecial structure. When x=0.4, glass fiber increase10mAh g-1discharge capacity andthe capacity loss of the initial value is14.49%at the20th cycle at the current density of25mA g-1. After doping of carbon, the discharge capacity of1.5Li2O-P2O5-xTiO2glassincrease by the increase of the content of carbon. The highest discharge capacity of1.5Li2O-0.4TiO2-P2O5/C glass is60.2mAh g-1, more than twice than1.5Li2O-0.4TiO2-P2O5glass, and10.9%capacity loss of the initial value at the20thcycle at the current density of25mA g-1.The results show that the network structure of Li2O-P2O5-TiO2glass can bechanged by changing the composition and forming glass fiber, thus the electrochemicalproperties improve. This provide a new way for the application of anode materials oflithium ion batteries and microbattery.