VO4^3- anion was used to partially substitute for PO43 in the Nasicon compound of LiSn2（PO4）3 via a sol-gel method. XRD analysis revealed that the VO4^3-substituted samples did not have a single LiSn2（PO4）3 phase,...VO4^3- anion was used to partially substitute for PO43 in the Nasicon compound of LiSn2（PO4）3 via a sol-gel method. XRD analysis revealed that the VO4^3-substituted samples did not have a single LiSn2（PO4）3 phase, and some secondary phases like SnO2 and SnP2O7 appeared. Introduction of the VO4^3- anion did not prevent the LiSn2（PO4）3 compound from decomposing during the initial lithiation; however the VO4^3- anion substitution remarkably enhanced the rate capability and cycling performance of the products because they reduced the charge transfer hnpedance, increased the lithium ion diffusion, and strengthened the role of the Li3PQ matrix due to the precipitation of the Li3V04 phase, Of the substituted samples, the sample with a nominal composition of LiSn2（PO4）2.5（VO4）0.5 delivered a capacity of 449.2 mA-h/g at a rate of 0.25 C after 25 cycles and 373.8 mA.h/g at 2 C rate. Those values surpassed some previous reports on LiSn2（PO4）3 and the LiSnz（PO4）3/C composites. Accordingly, the partial substitution of phosphorus by vanadium in LiSn2（PO4）3 is a feasible technique to remarkably improve its electrochemical properties.展开更多
基金Supported by the Natural Science Foundation of Hebei Province, China（No.E2016202358）.
文摘VO4^3- anion was used to partially substitute for PO43 in the Nasicon compound of LiSn2（PO4）3 via a sol-gel method. XRD analysis revealed that the VO4^3-substituted samples did not have a single LiSn2（PO4）3 phase, and some secondary phases like SnO2 and SnP2O7 appeared. Introduction of the VO4^3- anion did not prevent the LiSn2（PO4）3 compound from decomposing during the initial lithiation; however the VO4^3- anion substitution remarkably enhanced the rate capability and cycling performance of the products because they reduced the charge transfer hnpedance, increased the lithium ion diffusion, and strengthened the role of the Li3PQ matrix due to the precipitation of the Li3V04 phase, Of the substituted samples, the sample with a nominal composition of LiSn2（PO4）2.5（VO4）0.5 delivered a capacity of 449.2 mA-h/g at a rate of 0.25 C after 25 cycles and 373.8 mA.h/g at 2 C rate. Those values surpassed some previous reports on LiSn2（PO4）3 and the LiSnz（PO4）3/C composites. Accordingly, the partial substitution of phosphorus by vanadium in LiSn2（PO4）3 is a feasible technique to remarkably improve its electrochemical properties.
