Nanoengineering of Thin Film V₂O₅ Cathode Interfaces via Atomic Layer Deposition for use with Polymer Gel Ionic Liquid Electrolytes

Abstract

In this work we show high capacity and cycle‐life performance, for electrodeposited, crystalline V2O5 thin film cathodes protected by a 1 nm ALD alumina deposit for use with Li‐metal and ionic liquid electrolyte based microbatteries. Al2O3 coatings thicker than 1 nm are shown to decrease the performance of the V2O5 thin film cathodes. The ionic liquid outperforms an organic electrolyte at 1 C rates with an initial capacity of 148 mAh g‐1 and capacity retention of 97% at cycle 50. A polymer gel analogue of the ionic liquid electrolyte in combination with the 1 nm Al2O3 coated V2O5 had an initial capacity of 139 mAh/g with a capacity retention of 93.5% to cycle 800, illustrating high capacity and extended cycle life.