Lithium ion conductivity in hydrogen storage and battery materials

Howard, Matthew (2016). Lithium ion conductivity in hydrogen storage and battery materials. University of Birmingham. Ph.D.

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Abstract

In this thesis the role of lithium ion conductivity in lithium conducting garnets as potential solid state electrolytes for lithium ion batteries and lithium halide nitrides for solid state hydrogen storage materials is researched.
The role of order and disorder on in the lithium sublattice of garnet type materials is investigated. Showing that ordering can cause a change in the unit cell symmetry resulting a tetragonal unit cell. Due to the ordering a drop in the Li ion conductivity is observed. Through a small amount of trivalent doping into the lithium sublattice it is possible to create disorder and hence a change in the unit cell to cubic and an enhancement in the conductivity.
For the first time work conducted in this this shows evidence for possible H+/Li+ exchange occurring in air. This exchange was seen to have varying effects on the low temperature lithium ion conductivity. Highlighting the need to take care when preparing and measuring these materials. The structure of a antifluorite type lithium chloride nitride were resolved following inconclusive literature reports. It is shown for the first time that it is possible for these materials to hydrogenate these materials and they have potential as possible solid state hydrogen storage materials.
The ionic conductivity of the lithium halide nitrides were measured and compared to that of lithium nitride. And their hydrogen storage properties were related to the ionic conductivity.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):