Electrical Transport in Chemically Exfoliated Li_xCoO₂ in 2D Nanoflake Form

Layered oxides possess various novel electronic and magnetic phases, many of which remain either unexplained or continually debated. Li_xCoO₂ is one such material; one of the most commonly used cathode materials in rechargeable batteries, this oxide exhibits a rich landscape of properties, with many aspects still not fully understood. Li_xCoO₂ contains electrostatically stabilized layers, making it difficult to study in its few-layer, single-crystal form. Herein, a two-step process is utilized to chemically delithiate Li_xCoO₂ in the range 0.3<x<0.8. Li_xCoO₂ is then chemically exfoliated, producing nanoflakes 5-100nm thick. Electrical characterization of these individual nanoflakes reveals an insulating behavior upon contact formation, and suppression of metallic tendencies in the low-lithium range (x<0.75), likely due to termination effects of the surface lithium plane. Additionally, an anomaly in the temperature dependent resistance is observed in flakes of specific lithium content, indicating that this fabrication method is suitable for studying charge ordering phenomena in Li_xCoO₂. This technique offers potential for exploring Li_xCoO₂ in its two dimensional form, which has not been reported for single crystals to date.