Self‐Assembled Surfactant‐Polyoxovanadate Soft Materials as Tuneable Vanadium Oxide Cathode Precursors for Lithium‐Ion Batteries

Abstract

The mixing of [V 10 O 28 ] 6− decavanadate anions with a dicationic gemini surfactant ( gem ) leads to the spontaneous self‐assembly of surfactant‐templated nanostructured arrays of decavanadate clusters. Calcination of the material under air yields highly crystalline, sponge‐like V 2 O 5 ( gem ‐V 2 O 5 ). In contrast, calcination of the amorphous tetrabutylammonium decavanadate allows isolation of a more agglomerated V 2 O 5 consisting of very small crystallites ( TBA ‐V 2 O 5 ). Electrochemical analysis of the materials’ performance as lithium‐ion intercalation electrodes highlights the role of morphology in cathode performance. The large crystallites and long‐range microstructure of the gem ‐V 2 O 5 cathode deliver higher initial capacity and superior capacity retention than TBA ‐V 2 O 5 . The smaller crystallite size and higher surface area of TBA ‐V 2 O 5 allow faster lithium insertion and superior rate performance to gem ‐V 2 O 5 .