Hierarchically interlaced 2D copper iodide/MXene composite for high thermoelectric performance

Hierarchical layered architecture in thermoelectric materials works as an ad hoc methodology for strengthening the unique inherent properties. Here, we demonstrate an excellent thermoelectric behavior in novel 2D copper iodide nanoflakes by compositing with Ti3C2 MXene nanoinclusions. The interlaced architecture of CuI/Ti3C2 composite lifts the electrical conductivity over two orders by efficient charge transport mechanisms. The thermal conductivity of CuI/Ti3C2 composite are reduced by drastic suppression of mid-and high-frequency phonons by interfacial energy barrier scattering. Our structural engineering approach yields a massive power factor of 225 µW m-1 K-2 and a figure of merit value of 0.48 in CuI/5 vol.% Ti3C2 composite. We establish a straightforward approach of tuning the figure of merit in earth-abundant, non-toxic thermoelectric materials to develop future sustainable energy sources.