Lithium insertion in nanostructured titanates

Lithium insertion in nanostructured titanates

Borghols, W.J.H.

Mulder, F.M. (promotor)

Applied Sciences

Radiation, Radionuclides & Reactors

2010-03-29

Upon nano-sizing of insertion compounds several significant changes in Li-insertion behavior have been observed for sizes below approximately 50 nm. Although the origins of the phenomena are interrelated, the changes can be divided in three main observations. (1) The formation of new phases, leading to enhanced reactivity and extended capacities, which is most likely due to the lesser role of kinetic restrictions, and easier accommodation of strain in nanoscale compounds. (2) Thermodynamic changes due to the relatively increased impact of both surface and interface energy, and (3), the excess Li-storage on the surface of the particles in the form of Li2O. These three phenomena have a positive effect on the performance of the electrode material in a Li-ion battery application. The higher Li-capacities provide the electrode material with a higher energy density. Furthermore, the enhanced extend of the solid solution regime observed at lower Li-capacities, due to changes in the particle’s thermodynamics, supports better ionic mobility in the absence of a rate-limiting phase boundary. However, the relatively increase op the surface also enhances the negative effects, such as the formation of a solid electrolyte interface (SEI). Also, a Li-rich surface layer inherently shows poor Li-ion mobility, and effectively acts as a block for further intercalation of the bulk of the particle. The detailed insight in the nano-size related surface storage mechanisms discussed in this thesis forms an important basis for understanding the properties of nano-sized insertion materials. This knowledge supports future design of nano-sized electrode materials for Li-ion batteries and H-storage devices, potentially paving the way for the manufacturing of environmentally clean and highly efficient full-electrical cars.

Li-ion
nano
battery
TiO2
electrode

http://resolver.tudelft.nl/uuid:36edf5fe-f81e-4670-b30f-5d5b208db1fa

9789085930709

Institutional Repository

doctoral thesis

(c) 2010 Borghols, W.J.H.