Enhanced thermopower in an intergrowth cobalt oxide Li$_{0.48}$Na$_{0.35}$CoO$_{2}$

TL;DR

This study investigates a complex cobalt oxide with an intergrowth structure that exhibits significantly enhanced thermopower and promising thermoelectric properties, potentially useful for energy conversion applications.

Contribution

It reports the synthesis and characterization of Li$_{0.48}$Na$_{0.35}$CoO$_{2}$ with an intergrowth structure showing superior thermoelectric performance.

Findings

Large room-temperature thermopower of ~180 μV/K

Figure of merit reaches nearly 10^{-4} K^{-1} at 300 K

Enhanced thermoelectric properties compared to related compounds

Abstract

We report the measurements of thermopower, electrical resistivity and thermal conductivity in a complex cobalt oxide Li$_{0.48}$Na$_{0.35}$CoO$_{2}$, whose crystal structure can be viewed as an intergrowth of the O3 phase of Li$_{x}$CoO$_{2}$ and the P2 phase of Na$_{y}$CoO$_{2}$ along the c axis. The compound shows large room-temperature thermopower of $\sim$180 $\mu$V/K, which is substantially higher than those of Li$_{x}$CoO$_{2}$ and Na$_{y}$CoO$_{2}$. The figure of merit for the polycrystalline sample increases rapidly with increasing temperature, and it achieves nearly 10$^{-4}$ K$^{-1}$ at 300 K, suggesting that Li$_{x}$Na$_{y}$CoO$_{2}$ system is a promising candidate for thermoelectric applications.