Compositing effects for high thermoelectric performance of Cu 2 Se-based materials.

Thermoelectric materials can realize direct conversion between heat and electricity, showing excellent potential for waste heat recovery. Cu 2 Se is a typical superionic conductor thermoelectric material having extraordinary ZT values, but its superionic feature causes poor service stability and low mobility. Here, we reported a fast preparation method of self-propagating high-temperature synthesis to realize in situ compositing of BiCuSeO and Cu 2 Se to optimize the service stability. Additionally, using the interface design by introducing graphene in these composites, the carrier mobility could be obviously enhanced, and the strong phonon scatterings could lead to lower lattice thermal conductivity. Ultimately, the Cu 2 Se-BiCuSeO-graphene composites presented excellent thermoelectric properties with a ZT max value of ~2.82 at 1000 K and a ZT ave value of ~1.73 from 473 K to 1000 K. This work provides a facile and effective strategy to largely improve the performance of Cu 2 Se-based thermoelectric materials, which could be further adopted in other thermoelectric systems.