Phase Stabilization of In2Se3 by Disordered Ni Intercalation and its Enhanced Thermoelectrical Performance

Van der Waals (vdW) layered materials have gained significant attention owing to their distinctive structure and unique properties. The weak interlayer bonding in vdW layered materials enables guest atom intercalation, allowing precise tuning of their physical and chemical properties. In this work, a ternary compound, Ni x In 2 Se 3 (x = 0–0.3), with Ni randomly occupying the interlayers of In 2 Se 3 , is synthesized via an intercalation route driven by electron injection. The intercalated Ni atoms act as “anchor points” within the interlayer of In 2 Se 3 , which effectively suppresses the phase transition of In 2 Se 3 at elevated temperatures. Furthermore, the disordered Ni intercalation significantly enhanced the electrical conductivity of In 2 Se 3 through electron injection, while reducing the thermal conductivity due to the interlayer phonon scattering, leading to an improved thermoelectric performance. For instance, the thermoelectric figure of merit (ZT) of Ni 0.3 In 2 Se 3 increased by 86% (in-plane) and 222% (out-of-plane) compared to In 2 Se 3 at 500 °C. These findings not only provide an effective strategy to enhance the performance of layered thermoelectric materials but also demonstrate the potential of intercalation chemistry for expanding the application scope of van der Waals (vdW) layered materials.