High Performance Pillared Vanadium Oxide Xerogel Cathode for Lithium Ion Batteries
Aluminum Keggin ions were used as pillaring agents for the vanadium oxide xerogels. X-ray diffraction showed an interlayer spacing increase from 1.14 to 1.32 nm after pillaring, consistent with the size of the keggin ions (~1.3 nm), while still maintaining the layered V2O5 xerogel crystalline structure (Figure 1). Elemental analysis indicated an aluminum loading of 9 wt% in the pillared material. The pillared materials also demonstrate increased thermal stability and rate capabilities during cycling in coin cells, with capacities over 60% higher than those of the unpillared V2O5 xerogel. Additionally, the pillared materials retained more capacity during cycling at C/2. Pillaring the layered vanadium oxide xerogels improved both capacity retention and battery lifetime.
Figure 1. Diffraction patterns for V2O5 xerogel (a), pillared V2O5 xerogel (b), and pillared V2O5 xerogel after heat treatment in either air (c) or nitrogen (d). The dotted line is intended as a guide for the eye.