Ag_4V_2O_6F_2:An Electrochemically Active and High Silver Density Phase

摘要

Low-temperature hydrothermal techniques were used to synthesize single crystals of Ag4 This previously unreported oxide fluoride phase was characterized by single-crystal X-ray diffraction and IR spectroscopy and was also evaluated as a primary lithium battery cathode.Crystal data:monoclinic,space group P2_1 (No.14),with a = 8.4034(4) A,b = 10.548(1) A,c = 12.459(1) A,beta = 90.314(2)~°,and Z= 4.Ag_4V_2O_6F_2 (SVOF) exhibits two characteristic regions within the discharge curve,an upper plateau at 3.5 V,and a lower sloped region around 2.3 V from reduction of the vanadium oxide fluoride framework.The material has a nominal capacity of 251 mAh/g,with 148 mAh/g above 3 V.The upper discharge plateau at 3.5 V is nearly 300 mV over the silver reduction potential of the commercial primary battery material,Ag_2V_4O_(11) (SVO).