NASICON-Structured NaSn2(PO4)3 with Excellent High-Rate Properties as Anode Material for Lithium Ion Batteries

Advanced Li-ion batteries with high rate properties are in high demand and have generated much attention in the research community. Here, we present a simple sol-gel and solid-state reaction to synthesize NASICON-structured NaSn2(PO4)(3) as anode material for lithium-ion batteries. The obtained material exhibits excellent cycling performance and high rate capacity for half cell and LiFePO4/NaSn2(PO4)(3) full cell. Cyclic voltammograms (CV) and galvanostatic intermittent titration technique (GITT) were used to analyze the kinetics and thermodynamics of the electrode. Morphology and structure evolution of the NaSn2(PO4)(3) electrode after cycling were explored by transmission electron microscopy (TEM). These results showed nanoscale Sn was uniformly dispersed in the lithium phosphate matrix during the first discharge. It is proposed that the enhanced properties are attributed to the in situ formation of the ionic conductor as protective matrices, which prevents the aggregation of nanoparticles during the cycling and provides Li+ diffusion channels in the electrode for fast electrochemical reaction.