Electrochemical Properties and Sodium-Storage Mechanism of Ag2Mo2O7 as the Anode Material for Sodium-Ion Batteries
Authors:
Dr. Nan Chen,Dr. Yu Gao,Meina Zhang,Dr. Xing Meng,Prof. Chunzhong Wang,Prof. Yingjin Wei,Dr. Fei Du*,Prof. Gang Chen
Abstract：
Silver molybdate, Ag2Mo2O7, has been preparedby a conventional solid-state reaction. Its electrochemical properties as an anode material for sodium-ion batteries(SIBs) have been comprehensively examined by means of galvanostatic charge–discharge cycling, cyclic voltammetry,and rate performance measurements. At operating voltages between 3.0 and 0.01 V, the electrode delivered a reversible capacity of nearly 190 mA hg-1at a current density of 20 mA g-1after 70 cycles. Ag2Mo2O7 also demonstrateda good rate capability and long-term cycle stability, the ca-pacity reaching almost 100 mAhg-1at a current density of500 mAg-1, with a capacity retention of 55% over 1000 cycles. Moreover, the sodium storage process of Ag2Mo2O7 has been investigated by means of ex situ XRD, Raman spec-troscopy, and HRTEM. Interestingly, the anode decompose sinto Ag metal and Na2MoO4 during the initial discharge process, and then Na+ions are considered to be inserted into/extracted from the Na2MoO4 lattice in the subsequent cycles governed by an intercalation/deintercalation mechanism. Exsitu HRTEM images revealed that Ag metal not only remain sunchanged during the sodiation/desodiation processes, butis well dispersed throughout the amorphous matrix, therebygreatly improving the electronic conductivity of the working electrode. The “in situ” decomposition behavior of Ag2Mo2O7 is distinct from that of chemically synthesized, metal-nano-particle-coated electrode materials, and provides strong sup-plementary insight into the mechanism of such new anode materials for SIBs and may set a precedent for the design of further materials.
Published in Chemistry-A European Journal/Wiley-VCH on 9th APR. 2016
Paper Resource：
http://onlinelibrary.wiley.com/doi/10.1002/chem.201600224/abstract
