Chemical intercalation and electrochemical deintercalation of 2-aminoterephthalic acid into the layered titanoniobate HTiNbO5

Abstract

Layered titanoniobates are a versatile class of layered oxide materials and due to high theoretical capacities have been investigated for use in lithium batteries. Unfortunately, bulk titanoniobates often suffer from poor cycling performance or long charge/discharge durations especially during early cycling. Traditionally the materials have been synthesized as nanosheets, nanofibers or nanoparticles in an attempt to mitigate this reducing the required diffusion length. Here we propose a different approach by intercalating 2-aminoterephthalic acid molecules into the layered titanoniobate, HTiNbO5. This gives 2D ceramic nanosheets spaced apart with the organic species greatly increasing the available space for diffusion between layers. During initial electrochemical cycling of the intercalated material there is a significant reduction in the time taken for activation processes to complete when compared to the pure ceramic. This demonstrates how intercalation can be used to influence cycling behavior of bulk layered oxide ceramics.