SnSe Alloying Boosts PbSnS2 Crystals to Record Thermoelectric Efficiency of ZT 1.9 at 750 K, Enabling High-Efficiency Industrial Waste Heat Recovery

July 19, 2026

ACS Publications USA

Overview

Groundbreaking research has achieved a high thermoelectric efficiency with a ZT value of approximately 1.9 at 750 K in n-type Cl-doped (PbSnS2)1–x(SnSe)x crystals. This breakthrough, enabled by synergistic optimization of electrical and thermal transport, sets a new benchmark for PbSnS2-based thermoelectrics. The high-efficiency material demonstrates significant potential for converting industrial waste heat into electricity, contributing to enhanced energy efficiency and reduced greenhouse gas emissions.

In Depth

Key Findings

In a groundbreaking development, novel n-type Cl-doped (PbSnS2)1–x(SnSe)x crystals have achieved an exceptional thermoelectric figure of merit (ZT value) of approximately 1.9 at 750 K. This represents the highest efficiency reported for PbSnS2-based thermoelectric materials, significantly boosting the commercial viability of converting industrial waste heat directly into electrical energy. The breakthrough was made possible through a synergistic and simultaneous optimization of both electrical and thermal transport properties.

Technical / Clinical Details

The research team discovered that SnSe alloying imparts unique effects within the layered structure of PbSnS2 crystals. The introduction of SnSe induces localized lattice distortions and defects, which effectively enhance phonon scattering, thereby reducing thermal conductivity. Simultaneously, the electronic band structure is optimized, leading to improved electrical conductivity through increased carrier concentration and mobility. Specifically, for an optimized composition within a certain range of SnSe content (x), the effective mass of electrons decreases, and the Seebeck coefficient (thermoelectric power) is maximized. This combined effect improves the power factor (S²σ) and suppresses thermal conductivity (κ) in the ZT = S²σT/κ equation, resulting in the outstanding ZT value of 1.9 at 750 K. This represents a performance improvement of approximately 20-30% compared to previously reported similar materials.

Background & Context

Approximately 60% of global energy consumption is released into the environment as waste heat, contributing significantly to global warming and resource depletion. Thermoelectric materials have long been recognized as a promising clean energy technology that can convert this waste heat directly into electricity, but their commercial adoption has faced challenges related to efficiency and cost. The development of high-performance thermoelectric materials enables energy harvesting solutions in various sectors, including automotive exhaust heat recovery, industrial process waste heat utilization, and power generation for space probes. This research outcome significantly enhances the economic viability and practicality of thermoelectric generation in these application areas.

Strategic Significance & Outlook

The achievement of ZT 1.9 opens new horizons for PbSnS2-based thermoelectric materials. Future research will focus on evaluating the scalability of the material’s manufacturing process, its long-term stability, and mechanical strength. In particular, developing low-cost mass production techniques will be a crucial step towards commercialization. Furthermore, exploring different dopants and composite structures is expected to offer additional avenues for performance enhancement. This innovative material is anticipated to have a significant impact on future industries as a powerful tool for improving energy efficiency and realizing a sustainable society.

Source: https://pubs.acs.org/doi/10.1021/jacs.6c10915

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