In situ optical measurement of the rapid Li intercalation and deintercalation dynamics in colloidal 2D layered TiS2 nanodiscs.

We report the in situ optical measurements of the rapid Li intercalation and deintercalation dynamics in 2-dimensional (2D) layered transition metal dichalcogenide (TMD) with a nanoscale lateral dimension using thin films fabricated with size-controlled colloidal TiS2 nanodiscs. The films exhibiting high optical homogeneity, where the interband absorption changes near-linearly to the amount of intercalated Li, enabled facile optical probing of the intercalation dynamics overcoming the shortcomings of amperometry susceptible to complications from non-Faradaic processes. The time scale of Li intercalation and deintercalation was on the order of seconds in the nanodiscs of ∼100 nm lateral dimension, indicating sufficiently rapid dynamic control of the intercalation-induced material properties with a reduced lateral dimension.