Influence of Mesoporosity on Lithium-Ion Storage Capacity and Rate Performance of Nanostructured TiO2(B)

• Published in: Langmuir Vol. 28; no. 5; pp. 2897 - 2903
• Main Authors: Dylla, Anthony G., Lee, Jonathan A., Stevenson, Keith J.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07.02.2012
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Porous materials; Binary compound; Nanoparticle; Transition element compounds; Ethylene; Insertion; Purity; Ion transport; Voltammetry; Nanostructure; Crystallinity; Porous material; Mesoporosity; Template; Electrodes; Electrolyte; Storage capacity; Titanium oxide; Structure; Block copolymer; Diameter; Glycol; Lithium ion; Electrons
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la2037229

Here, we present the Li+ insertion behavior of mesoporous ordered TiO2(B) nanoparticles (meso-TiO2(B)). Using presynthesized 4 nm TiO2(B) nanoparticles as building blocks and a commercially available ethylene glycol-propylene glycol block copolymer (P123) as a structure-directing agent, we were able to produce mesoporous structures of high-purity TiO2(B) with nanocrystallinity and mesopore channels ranging from 10 to 20 nm in diameter. We compared the Li+ insertion properties of nontemplated TiO2(B) nanoparticles (nano-TiO2(B)) to meso-TiO2(B) via voltammetry and galvanostatic cycling and found significant increases in overall Li+ insertion capacity for the latter. While nano-TiO2(B) and meso-TiO2(B) both show surface charging (pseudocapacitive) Li+ insertion behavior, meso-TiO2(B) exhibits a higher overall capacity especially at high charge rates. We attribute this effect to higher electrode/electrolyte contact area as well as the improved electron and ion transport in meso-TiO2(B). In this study, we have demonstrated the influence of both nanostructuring and mesoporosity on Li+ insertion behavior by rationally controlling the overall architecture of the TiO2(B) materials.