Waste-heat-recovery systems and power generation.
Thermoelectric performance is measured by the dimensionless figure-of-merit, ZT. A good thermoelectric material has high ZT; however, it has proven to be a challenge to increase ZT from the longstanding 1.0 in thermoelectric bulk materials to higher values by minimizing the lattice contribution through the concept of the nanocomposite. The key idea of the nanocomposite is to create grains or inclusions that scatter the phonons without deteriorating electron transport. More generally, a good thermoelectric material should behave as a "phonon-glass-electron-crystal" with a high charge carrier mobility and low thermal conductivity.
This invention comprises a novel method for producing nanocomposite thermoelectric materials with high thermoelectric performance. Metals such as copper and selenium are subject to high-energy ball milling to form Cu2Se nanopowders. Afterwards, the nanopowders are consolidated into bulk samples via a hot pressing method using a conventional furnace hot press. The Cu2Se crystals combine ordered Se layers and disordered Cu layers in the unit cell, which promises a low lattice thermal conductivity and moderate electrical conductivity that are essential for a good thermoelectric material. A ZT of ~1.6 at 700°C is achieved in the β-phase of copper selenide (Cu2Se).
- High thermoelectric performance
- Fabrication method is simple, cost effective, controllable and scalable
- Only two common elements (copper and selenium) are involved