Thermoelectric (TE) conversion offers carbon-free power generation from geothermal, waste, body or solar heat, and shows promise to be the next-generation energy conversion technology. At the core of such TE conversion, there lies an all solid-state thermoelectric device which enables energy conversion without the emission of noise, vibrations, or pollutants. To this, a POSTECH research team proposed a way to design the next-generation thermoelectric device that exhibits remarkably simple manufacturing process and structure compared to the conventional ones, while displaying improved energy conversion efficiency using the spin Seebeck effect (SSE).