Topotactic synthesis of alternately stacked Ca3Co4O9/γ-Na0.66CoO2 composite with nanoscale layer structure

Abstract

A novel process has been introduced to synthesize an alternately stacked Ca₃Co₄O₉/γ-Na_0.66CoO₂ composite with nanostructured layers and high c-axis orientation. The thickness of each layer is about 60–100 nm. The maximum power factor at 1000 K is 6.3 × 10⁻⁴ W m⁻¹ K², which is about 50% higher than that of conventional Ca₃Co₄O₉ ceramics.