Investigation of Yttrium and Polyvalent Ion Intercalation into Nanocrystalline Vanadium Oxide

Abstract

The electrochemical reactivity of cations such as Ca2+,Ca2+, Mg2+,Mg2+, and Y3+Y3+ into crystalline V2O5V2O5 materials was investigated. The ionic diffusion constant of Li+Li+ and Y3+Y3+ into microcrystalline and nanocrystalline V2O5V2O5 was measured by the galvanostatic intermittent titration technique. The Y3+Y3+ ion diffusion constant into a 500 nm crystalline V2O5V2O5 was found to be approximately two orders of magnitude lower than for the Li+Li+ ion. In order to enable practical intercalation of Y3+,Y3+, a nanocrystalline V2O5V2O5 was fabricated through a combustion flame synthesis technique. For the first time, reversible electrochemical intercalation of Y3+Y3+ into a host structure was shown to be feasible. An asymmetric hybrid cell configuration was utilized in order to provide a reversible counter electrode during intercalation. Preliminary data indicates Y3+Y3+ can be reversibly intercalated into V2O5V2O5 with apparent gravimetric capacities exceeding that of Ca2+,Ca2+, Mg2+,Mg2+, or Li+Li+ over the limited voltage range of 2.5 to 4.2 V (Li/Li+).(Li/Li+). The concept of polyvalent intercalation is discussed relative to intercalation, pseudocapacitance, apparent specific capacity, and practical energy storage systems. © 2001 Telcordia Technologies. All rights reserved.