Interconnected mesoporous V2O5 electrode: impact on lithium ion insertion rate

Abstract

Here we introduce a strategy for creating nanotube array electrodes which feature periodic regions of porous interconnections providing open pathways between adjacent nanotubes within the array, utilizing a combination of anodized aluminum oxide growth modification (AAO) and atomic layer deposition. These porous interconnected structures can then be used as testbed electrodes to explore the influence of mesoscale structure on the electrochemical properties of the interconnected mesoporous electrodes. Critically, these unique structures allow the solid state lithium diffusion pathways to be held essentially constant, while the larger structure is modified. While it was anticipated that this strategy would simply provide increased mass loading, the kinetics of the Li⁺ ion insertion reaction in the porous interconnected electrodes are dramatically improved, demonstrating significantly better capacity retention at high rates than their aligned counterparts. We utilize a charge deconvolution method to explore the kinetics of the charge storage reactions. We are able to trace the origin of the structural influence on rate performance to electronic effects within the electrodes.