Improve thermoelectric performance of Bi2Te3 by incorporation of Mo2C MXene with N-type conductivity

In this paper, the thermoelectric (TE) performance of Bi 2 Te 3 was improved by the incorporation of Mo 2 C MXene, which is a novel two-dimensional material with moderate TE performance. The TE properties of Mo 2 C MXene were characterized from bulk samples bonded with 5 wt% Al sintered by spark plasma sintering (SPS) at 623 K for 6 min. Due to the very weak TE performance of Al, the performance of Mo 2 C MXene/Al composite reflects that of Mo 2 C MXene. It is an N-type conductor with the Seebeck coefficient of − 9.25 µV/K at 600 K. This is the first report to characterize the TE performance of Mo 2 C MXene bulk samples. Thereafter, Bi 2 Te 3 /Mo 2 C MXene composite powders were prepared from Mo 2 C MXene powers and precursors of Bi 2 Te 3 by hydrothermal method at 453 K for 24 h. The bulk samples of Bi 2 Te 3 incorporated with Mo 2 C MXene was obtained by SPS at 523 K for 7 min. The composites are N-type conductors. The electrical conductivity was remarkably increased with the content of Mo 2 C MXene, while the thermal conductivity slightly decreased. The sample with 5 vol% Mo 2 C MXene showed the optimal thermoelectric properties, and its ZT value was 0.26 at 473 K. At 450 K, the ZT value (~ 0.25) of that sample was 78.6% higher than that of Bi 2 Te 3 (~ 0.14). This is the first report on regulating TE performance by the incorporation of Mo 2 C MXene, a 2D material with intrinsic TE performance.