High-temperature Bi2Te3 thermoelectric generator fabricated using Cu nanoparticle paste bonding

For the successful commercialization of Bi2Te3-based thermoelectric generator (TEG) devices, not only highly efficient TE materials, but also reliable bonding materials with high thermal stability are essential. In this study, we investigated the application of Cu nanoparticle paste (CNP) bonding for increasing the operating temperature of Bi2Te3-based TEG devices. Six-chip TEG devices were fabricated by joining surface-metalized Bi2Te3-based TE chips and Cu electrodes by CNP bonding. The optimal bonding was achieved when spark plasma sintering was carried out at 310–320 °C and 15 MPa. The 6-chip Bi2Te3-based TEG devices showed a maximum output power of 50–60 mW at the hot-side temperature of 400 °C ( ∆ T = 380 °C) and maintained almost the same output power after five thermal cycles. The scanning electron microscopy images of the thermally cycled electrodes further confirmed the robustness of the Cu nanoparticle joints. This work provides an effective method for joining TE chips and Cu electrodes for high-temperature TEG devices.