Liquid Phase Exfoliation of Two Dimensional Transition Metal Oxides for Electrochemical Applications

Transition metal oxides (TMOs) represent an attractive family of materials for their electrochemical charge storage properties. The theory is mainly based on the two dimensional layered structure of these materials providing increased surface area for charge storage alongside decreased diffusion paths for lithium and other intercalation ions. Much work is done into the exfoliation of two dimensional materials such as V₂O₅ and anatase TiO₂, however many methods require multistep chemical processes which can be lengthy and introduce the possibility of unwanted by-products. Liquid phase exfoliation by sonolysis provide a simple cost effective method to exfoliate these two dimensional TMOs to produce relatively thin nanoflakes with impressive charge storage capacities, cycle lifetime and efficiency. This work aims to show the charge storage capabilities of V₂O₅ and anatase TiO₂ which both exceed their theoretical capacities without the use of polymer binders or conductive additives. Sonication of bulk material in common solvents for a relatively short time scale produces desirable nanoflakes while ultrasonic spraying produces uniform electrodes which are tested electrochemically vs. Li/Li⁺. In conclusion, this project, using simple methodology, produces electrochemically impressive two dimensional materials.