Preparation and Thermoelectric Properties of Na_xCoO₂/Co₃O₄ Layered Nano-Composite

Abstract

Na_xCoO₂/Co₃O₄ layered nano-composite was prepared through the exfoliation, stacking, and sintering processes. Although almost no electrical conduction was observed at low temperatures, a significant increase in conductivity was observed above 750 K, and it reached 1.2×10² Scm⁻¹ at 1200 K, which is comparable to that of Na_0.7CoO₂. Seebeck coefficient also largely increased above 750 K. This observation might be associated with the electrical behaviors of Co₃O₄ at high temperature.