 Manganese Telluride MNT-E is a promising material for lead-free mid-temperature range thermoelectric energy conversion. However, its performance is limited due to cost and environmental concerns. A new approach was developed to improve the material's performance by introducing SB-GO and SB-GUS alloying. This resulted in a record high figure of merit, ZT, of 1.6 at 873K compared to previous values of 1.4. The material also exhibits excellent power factor and low lattice thermal conductivity, making it ideal for waste-heat recovery and power generation applications. This article was authored by Shatsata Zilkaful, Chih-Chao Wang, Xuame Zhang, and others.