High-performance Thermoelectric Materials Research Articles

Multinary Tetrahedrite (Cu12-x-yMxNySb4S13) Nanoparticles: Tailoring Thermal and Optical Properties with Copper-Site Dopants.

Tetrahedrite (Cu12Sb4S13) is an earth-abundant and nontoxic compound with prospective applications in green energy technologies such as thermoelectric waste heat recycling or photovoltaic power generation. A facile, one-pot solution-phase modified polyol method has been developed that produces high-purity nanoscale tetrahedrite products with exceptional stoichiometric and phase control. This modified polyol method is used here to produce phase-pure quaternary and quintenary tetrahedrite nanoparticles doped on the Cu-site with Zn, Fe, Ni, Mn, or Co. This is the first time that Cu-site codoped quintenary tetrahedrite and Mn-doped quaternary tetrahedrite have been produced by a solution-phase method. X-ray diffraction shows phase-pure tetrahedrite, while scanning and transmission electron microscopy show the size and morphology of the nanomaterials. Energy dispersive X-ray spectroscopy confirms nanoparticles have near-stoichiometric elemental compositions. Thermal stability of quintenary codoped tetrahedrite material is analyzed using thermogravimetric analysis, finding that codoping with Mn, Fe, Ni, and Zn increased thermal stability while codoping with cobalt decreased thermal stability. This is the first systematic study of the optical properties of quaternary and quintenary tetrahedrite nanoparticles doped on the Cu-site. Visible-NIR diffuse reflectance spectroscopy reveals that the quaternary and quintenary tetrahedrite nanoparticles have direct optical band gaps ranging from 1.88 to 2.04 eV. Data from thermal and optical characterization support that codoped tetrahedrite nanoparticles are composed of quintenary grains. This research seeks to enhance understanding of the material properties of tetrahedrite, leading to the optimization of sustainable, nontoxic, and high-performance photovoltaic and thermoelectric materials.

Enhanced thermoelectric properties of Mg2Si0.3Sn0.7 via Bi-doping under high pressure

A series of n-type Mg2(Si0.3Sn0.7)1-xBix compounds with 0≤x≤0.02 were successfully synthesized through a combined approach involving solid-state reaction, high-pressure synthesis, and spark plasma sintering techniques. The method yielded homogeneously distributed single-phase materials at the micron scale, although minor compositional variations were detected within nanoscale precipitates embedded in the grains. The sample with Bi content of 0.01 exhibited enhanced thermoelectric properties, reaching a peak thermoelectric figure of merit (ZT) of 1.45 at 700 K while maintaining an average ZT of about 1.1 over the temperature range of 300−773 K. The enhancement in thermoelectric performance is ascribed to the optimized carrier concentration, band convergence, and refined microstructure. The findings suggest a simplified approach to doping that could be beneficial in creating high-performance thermoelectric materials for energy conversion.

Recent Developments on Flexible Materials for Thermoelectrics

In recent decades, thermoelectric materials have gained a significant attention due to their ability to directly convert waste heat into electricity. While extensive research has been focused on enhancing the thermoelectric properties of inorganic bulk materials, a new frontier has emerged in this area as flexible thermoelectric materials. These flexible thermoelectrics are driven by the limitations posed by the rigidity, less functional and toxicity of conventional inorganic thermoelectric materials. Despite notable achievements in the development of high-performance flexible thermoelectric materials, they still pose inferior figure of merit (zT) in comparison to their inorganic counterparts. This review encompasses various aspects of flexible thermoelectric materials including theoretical foundations which highlight the principles that explain the concepts and parameters of thermoelectricity to enhance the overall performance, serving as a foundation for understanding the subsequent developments. Further it is overviewed in detail the corresponding state of the art in development of conducting thermoelectric polymers, inorganic-polymer composites, carbon-based thermoelectric and inorganic thermoelectrics on flexible substrates to enhance their thermoelectric performances. Finally it includes the overlook to the future of flexible thermoelectric for wearable thermoelectrics.

Boosting Thermoelectric Performance of PbBi2Te4 via Reduced Carrier Scattering and Intensified Phonon Scattering.

Materials with low intrinsic lattice thermal conductivity are crucial in the pursuit of high-performance thermoelectric (TE) materials. Here, the TE properties of PbBi2Te4-xSex (0 ≤ x ≤ 0.6) samples are systematically investigated for the first time. Doping with Se in PbBi2Te4 can simultaneously reduce carrier concentration and increase carrier mobility. The Seebeck coefficient is significantly increased by doping with Se, based on the density functional theory calculation, it is shown to be due to the increased bandgap and electronic density of states. In addition, the lattice strain is enhanced due to the difference in the size of Se and Te atoms, and the multidimensional defects formed by Se doping, such as vacancies, dislocations, and grain boundaries, enhance the phonon scattering and reduce the lattice thermal conductivity by about 37%. Finally, by using Se doping to reduce carrier concentration and thermal conductivity, a large ZTmax = 0.56 (at 574K) is achieved for PbBi2Te3.5Se0.5, which is around 64% larger than those of the PbBi2Te4 pristine sample. This work not only demonstrates that PbBi2Te4 is a potential medium temperature thermoelectric material, but also provides a reference for enhancing thermoelectric properties through defect and energy band engineering.

Ag, Pb co-doped SnSe high performance thermoelectric materials

SnSe, as a novel thermoelectric material, has ultrahigh thermoelectric properties in its single crystals, while the thermoelectric properties of polycrystals need to be further improved. Introducing atomic disorder to increase the lattice anharmonicity of the material is a typical strategy to reduce the lattice thermal conductivity and enhance the thermoelectric properties. Ag and Pb co-doping increased the effective carrier mass of the samples, and the resultant strong phonon scattering leads to a drastic decrease of the lattice thermal conductivity over the whole temperature range, and at the same time, optimizes the energy-band structure of SnSe, which finally significantly increases the Seebeck coefficient of SnSe. However, the electrical properties of SnSe deteriorate due to Pb elemental doping, so we introduce Ag atoms with higher intrinsic conductivity to increase its conductivity. At 800 K, the electrical conductivity of the Sn0.82Ag0.08Pb0.1Se sample is about twice as much as that of the undoped SnSe, and the thermal conductivity is 0.28 W mK−1. The ZT value of Sn0.82Ag0.08Pb0.1Se sample peaked at ∼1.33 at 800 K compared to only ∼0.48 for undoped SnSe. The ZT ave value of Sn0.82Ag0.08Pb0.1Se sample in the temperature range of 300–500 K was ∼0.36 compared to only ∼0.083 for undoped SnSe samples.

Stability, thermodynamic, electronic, and thermoelectric properties of triclinic Cu[formula omitted]Se structure

The conversion of heat into electricity using the thermoelectric effect is a crucial issue to tackle the ever-increasing global energy consumption. Cu2Se is one of the high-performance thermoelectric materials due to its liquid-like atomic structure, which minimizes the phonon-derived thermal conductivity. Nevertheless, the unambiguous atomic structure of the low-temperature phase, α-Cu2Se, remains controversial. By employing a combination of theoretical approaches including an evolutionary algorithm for structural searching, density functional theory, and lattice dynamics, the α-Cu2Se phase is proposed to crystalize in the dynamically stable triclinic Cu2Se structure (s.g. P1) which can be regarded as a monoclinic polymorph (s.g. P21/c†) through slight distortion. The corresponding heat capacity (CV) and Debye temperature (ΘD) are 0.37 J/g K and 276 K, respectively, indicating low thermal conductivity in the material. The semiconducting P1 phase possesses an indirect gap of 1.0 eV. Additionally, based on the Boltzmann transportation theory, fundamental thermoelectric parameters around the transition temperature (300–500 K) are investigated. Beyond the semiconducting phase, a novel metallic phase identified as the triclinic P1̄ phase is also discovered, exhibiting a two-dimensional (2D) crystal geometry.

Developing High-Performance and Low-Cost Paint Thermoelectric Materials for Low-Midtemperature Applications.

Most thermoelectric (TE) materials used to convert heat energy into electrical energy are expensive and, to a certain degree, toxic. Moreover, due to the chemical complexity in the synthesis process, some of the TE materials are not reproducible. Similarly, the scarcity of TE materials hampers their scalability. To address the above issues, this study presents an inexpensive, nontoxic, scalable, and highly reproducible paint-based TE module for the conversion of heat energy to electrical energy. Transport properties with structural analysis indicate that the electrical conductivity of the paint TE material is controlled by the concentration of graphite and sodium silicate, while the Seebeck coefficient is dominated by the ratio of n- and p-type Bi-Sb-Te. The results indicate that the as-developed TE module can withstand an operating temperature of up to 160 °C. At a temperature of 57 °C, the highest power factors of the as-synthesized n- and p-type TE paints are 1.34 and 1.42 μW/(cm K2), respectively. It is also found that the TE module can have a higher output voltage when the cold side of the TE module is allowed to float in the air in comparison to that when it is in contact with the human body. The performance of the paint-based TE module is measured on five parts of the body, namely, the chest, palm, leg, wrist, and neck; the wrist has the highest open-circuit voltage of 1.9 mV, indicating its suitability for wearable applications. Finally, at a temperature gradient of 30 °C, a maximum output power of 6.8 μW is attained.

High thermoelectric performance near the Mott–Ioffe–Regel limit in CuxS0.6Te0.4 meta-phases

The meta-phase, characterized by crystal-amorphicity duality in the extremely special case, has garnered considerable interests due to its glass-like thermal conductivity and tunable conduction mechanisms for carriers. However, the impact of crystal-amorphicity duality on the electrical and thermal transports remains elusive, and the carrier concentration in the meta-phase is rarely tuned in a wide range for optimized thermoelectric properties. Herein, through a combination of molecular dynamic simulations, chemical bonding analysis, and structural characterization, we reveal the glass-like distribution of Cu cations modulated by the mismatched S/Te anions in CuxS0.6Te0.4 meta-phase. Such unique atomic structure leads to hopping conduction of carriers and extremely low thermal conductivity. The carrier concentration is effectively optimized by tuning the Cu content in CuxS0.6Te0.4. Finally, we achieve a high zT of 1.4 at 900 K for Cu2.01S0.6Te0.4 sample, which is three times larger than those of Cu2S and Cu2Te matrixes. Remarkably, the high zT value is attained near the Mott–Ioffe–Regel Limit where the carrier mean free path is close to the average atomic distance. Our findings shed light on a new route to discovering high-performance thermoelectric materials.

Suppressed lattice thermal conductivity in porous compounds for high-performance thermoelectric applications

Traditional zinc blende semiconductor materials of groups II–VI and III–V exhibit excellent electrical properties, yet suffer from oversized lattice thermal conductivity, causing poor thermoelectric performance. Herein, we have explored an alternative metastable phase of those materials, namely, porous phase. Compared with the stable zinc blende structure, which has simple crystal structure with nearly isotropic bonding feature, porous compounds exhibit complex bonding hierarchy and softened acoustic phonon modes with strong anharmonicity, reducing the lattice thermal conductivity by nearly two orders of magnitude. As an outstanding representative of porous compound family, the suppressed thermal conductivity [∼0.76 W/(m K) at room temperature] combined with enhanced Seebeck coefficient makes porous MgTe a high-performance thermoelectric material with figure of merit above unity at n-type doping and high temperature. This work highlights the important role of intrinsic porosity in design of high-performance thermoelectric materials with low lattice thermal conductivity.

Phonon transport properties of Janus Pb2 XAs (X = P, Sb, and Bi) monolayers: A DFT study

Grasping the underlying mechanisms behind the low lattice thermal conductivity of materials is essential for the efficient design and development of high-performance thermoelectric materials and thermal barrier coating materials. In this paper, we present a first-principles calculations of the phonon transport properties of Janus Pb2PAs and Pb2SbAs monolayers. Both materials possess low lattice thermal conductivity, at least two orders of magnitude lower than graphene and h-BN. The room temperature thermal conductivity of Pb2SbAs (0.91 W/mK) is only a quarter of that of Pb2PAs (3.88 W/mK). We analyze in depth the bonding, lattice dynamics, and phonon mode level information of these materials. Ultimately, it is determined that the synergistic effect of low group velocity due to weak bonding and strong phonon anharmonicity is the fundamental cause of the intrinsic low thermal conductivity in these Janus structures. Relative regular residual analysis further indicates that the four-phonon processes are limited in Pb2PAs and Pb2SbAs, and the three-phonon scattering is sufficient to describe their anharmonicity. In this study, the thermal transport properties of Janus Pb2PAs and Pb2SbAs monolayers are illuminated based on fundamental physical mechanisms, and the low lattice thermal conductivity endows them with the potential applications in the field of thermal barriers and thermoelectrics.

A novel solution-based approach for PANI growth on PEDOT:PSS film to fabricate PEDOT:PSS/PANI-H2SO4 bilayer and its application in thermoelectric energy harvesting

The construction of bilayer or multilayer structures has been recognized as one of the most promising strategies for exploring high-performance organic thermoelectric materials. In this study, a novel poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate)/polyaniline (PEDOT:PSS/PANI) bilayer film was successfully fabricated through a facile solution method, wherein PANI was initially dissolved in concentrated sulfuric acid (H2SO4) to form a homogenous solution which was then applied to the PEDOT:PSS film. Benefiting from the introduction of PANI, the Seebeck coefficient of the PEDOT:PSS film was improved from 16.34 to 23.17 μV K−1, while the electrical conductivity experienced a remarkable enhancement, reaching 723.34 S cm−1. Accordingly, the resulting PEDOT:PSS/PANI-H2SO4 bilayer film demonstrated a high power factor (PF) of 38.83 μW m−1 K−2, which further increased to 44.38 μW m−1 K−2 at 380 K. Hence, this technique offers a facile method to fabricate large-scale PEDOT:PSS/PANI-H2SO4 bilayer films, expanding application fields of PANI via solution-based preparation.

High-performance thermoelectric properties of Cu2Se fabricated via cold sintering process

The concept of a ‘phonon-liquid electron-crystal’ has received significant interest in recent years, with copper selenide (Cu2Se) emerging as one of the high-performance thermoelectric materials within this framework. This study focuses on the fabrication of Cu2Se bulk pellets through a low-temperature sintering method known as cold sintering process (CSP). The introduction of a liquid phase (thiol-amine solution) in this process facilitates the dissolution and precipitation of ion/atom clusters, resulting in sample densification. Remarkably, a sample density of nearly 90 % is achieved at a low sintering temperature of only 473 K. Furthermore, this CSP approach preserves the morphology of the Cu2Se precursor powders and effectively inhibits grain growth. Consequently, the lattice thermal conductivity of the CSP samples is significantly reduced, attributed to enhanced grain boundary phonon scattering. This leads to a substantial improvement in the figure-of-merit (ZT), increasing from 0.65 at 800 K in the hot-pressed sample to 2.13 at 800 K in the CSP sample. The advantages of CSP can be extended beyond Cu2Se, as it holds promise for enhancing the performance of various high-performance thermoelectric materials.

High-Throughput Strategies in the Discovery of Thermoelectric Materials.

Searching for new high-performance thermoelectric (TE) materials that are economical and environmentally friendly is an urgent task for TE society, but the advancements are greatly limited by the time-consuming and high cost of the traditional trial-and-error method. The significant progress achieved in the computing hardware, efficient computing methods, advance artificial intelligence algorithms, and rapidly growing material data have brought a paradigm shift in the investigation of TE materials. Many electrical and thermal performance descriptors are proposed and efficient high-throughput (HTP) calculation methods are developed with the purpose to quickly screen new potential TE materials from the material databases. Some HTP experiment methods are also developed which can increase the density of information obtained in a single experiment with less time and lower cost. In addition, machine learning (ML) methods are also introduced in thermoelectrics. In this review, the HTP strategies in the discovery of TE materials are systematically summarized. The applications of performance descriptor, HTP calculation, HTP experiment, and ML in the discovery of new TE materials are reviewed. In addition, the challenges and possible directions in future research are also discussed.

Construct Amorphous Polymer Interface to Enhance the Thermoelectric Performance of Commercial Bi0.5Sb1.5Te3 Materials.

Interfaces, such as grain boundaries and phase boundaries in thermoelectric (TE) materials, play a crucial role in the carrier/phonon transport. Accurate control of the features of interfaces, including composition, crystalline nature, and thickness may give rise to a promising pathway to break the trade-off between phonon and carrier transport properties, which is essential to design high-performance TE materials. In this work, the amorphous polymer interface (API) layer is introduced to the p-type commercial Bi0.5Sb1.5Te3 (BST) TE material by the liquid-phase sintering process. Due to the larger mismatch in the acoustic impedance or phonon spectra between the amorphous polymer layer and the BST phase, the additional interfacial thermal resistance is introduced, which results in a large decrease in lattice thermal conductivity. It is found that the interfacial thermal resistance at the API is much higher than that of normal grain boundary and hetero interface reported in the literature. Conversely, taking advantage of the strong electron and phonon scattering, a large net get of ZT was achieved. A maximum ZT of ∼1.22 at 350 K was obtained in the BST/polyimide-0.5% sample, which is considerably greater than that of the commercial BST matrix (∼0.99 at 350 K). Furthermore, the optimized BST/polymer sample also exhibited almost 20% enhancement in hardness compared with the pure BST sample. This work has opened a new window for designing high-performance TE composites, which may extend to other material systems.

Facile synthesize and enhanced thermoelectric performance of PbS with Cl doping and PbSe alloying

Besides inferior conversion efficiency, the widespread application of thermoelectric materials currently faces the challenges of the rare and high cost of constituent elements, complex and time-consuming synthesis. Therefore, it is urgent to develop facile synthesized methods and high-performance thermoelectric materials consisting of elements with earth-abundance and low cost. Meeting above partial requirement, lead sulfide (PbS) recently was identified as a potential thermoelectric material to substitute current commercial PbTe. In this paper, a one-step high-pressure method was employed to facile and fast synthesis of PbS. Trace Cl doping tunes the carrier concentration of PbS effectively, which optimizes the electrical transport properties. Further PbSe alloying sharply reduces the thermal conductivity of PbS. Therefore, an enhanced zT∼1.0 @ 700 K was obtained for PbS doped with 0.3 at% Cl and alloyed with 25 at% PbSe, which is comparable to the commercially applied PbTe. These results indicate that high-pressure combing with Cl-doping and PbSe-alloying provide a facile method and strategy to fabricate high-performance PbS-based thermoelectric materials.

High-Performance Ag 2 Se/Methyl Cellulose Thermoelectric Composites for Flexible Power Generators

Flexible thermoelectric generators (FTEGs) offer a promising solution for powering wearable electronics, while their practical applications are mainly obstructed by the moderate properties of flexible thermoelectric (TE) materials. Here, flexible Ag 2 Se nanowire (NW)/methyl cellulose (MC) composite films were developed via facile screen-printing technology combined with cold pressing and annealing treatment, and a highest power factor of 1,641.58 μW m −1 K −2 at 360 K was achieved. The reasons for the high TE performance of the Ag 2 Se NW/MC composite films were because, after the annealing treatment, the Ag 2 Se NWs were sintered to form conductive network structures, the crystallinity of Ag 2 Se was markedly enhanced, and the content of insulating phase MC in the composite film was decreased. The Ag 2 Se NW/MC composite film held appreciable flexibility, as its room-temperature power factor (1,312.08 μW m −1 K −2 ) can retain ~93% after bending for 1,000 cycles at a radius of 4 mm. Furthermore, the assembled FTEG consisting of 4 strips can generate a maximal power density of 3.51 W m −2 at a temperature difference of 14.1 K. Our results open an effective and large-scale strategy for fabricating high-performance flexible TE materials and energy-harvesting devices.

Hidden structures: a driving factor to achieve low thermal conductivity and high thermoelectric performance.

The long-range periodic atomic arrangement or the lack thereof in solids typically dictates the magnitude and temperature dependence of their lattice thermal conductivity (κlat). Compared to crystalline materials, glasses exhibit a much-suppressed κlat across all temperatures as the phonon mean free path reaches parity with the interatomic distances therein. While the occurrence of such glass-like thermal transport in crystalline solids captivates the scientific community with its fundamental inquiry, it also holds the potential for profoundly impacting the field of thermoelectric energy conversion. Therefore, efficient manipulation of thermal transport and comprehension of the microscopic mechanisms dictating phonon scattering in crystalline solids are paramount. As quantized lattice vibrations (i.e., phonons) drive κlat, atomistic insights into the chemical bonding characteristics are crucial to have informed knowledge about their origins. Recently, it has been observed that within the highly symmetric 'averaged' crystal structures, often there are hidden locally asymmetric atomic motifs (within a few Å), which exert far-reaching influence on phonon transport. Phenomena such as local atomic off-centering, atomic rattling or tunneling, liquid-like atomic motion, site splitting, local ordering, etc., which arise within a few Å scales, are generally found to drastically disrupt the passage of heat carrying phonons. Despite their profound implication(s) for phonon dynamics, they are often overlooked by traditional crystallographic techniques. In this review, we provide a brief overview of the fundamental aspects of heat transport and explore the status quo of innately low thermally conductive crystalline solids, wherein the phonon dynamics is majorly governed by local structural phenomena. We also discuss advanced techniques capable of characterizing the crystal structure at the sub-atomic level. Subsequently, we delve into the emergent new ideas with examples linked to local crystal structure and lattice dynamics. While discussing the implications of the local structure for thermal conductivity, we provide the state-of-the-art examples of high-performance thermoelectric materials. Finally, we offer our viewpoint on the experimental and theoretical challenges, potential new paths, and the integration of novel strategies with material synthesis to achieve low κlat and realize high thermoelectric performance in crystalline solids via local structure designing.

Enhancing thermoelectric properties of Ca3Co4O9 ceramics through oscillatory pressure sintering

Oscillatory Pressure Sintering (OPS) has been demonstrated to be a favorable manufacturing approach for the control of fine and uniform distribution of grains in various ceramic systems, which can lead to enhanced densification and thus improved physical and mechanical properties. In this study, OPS was utilized to prepare pure Ca3Co4O9 thermoelectric material. The results show that the electrical properties and thermoelectric properties of Ca3Co4O9 prepared by OPS are superior to those of samples sintered by conventional hot pressing (HP) without oscillation. This may be attributed to the better alignment of plate-like grains in the OPS samples, which increase electrical conductivity, and also the higher density of grain boundaries that enhance the phonon scattering and, thus, the reduction of thermal conductivity. This study suggests that a straightforward oscillatory pressure sintering approach can be utilized to obtain high-quality and high-performance thermoelectric materials without the need for doping, templating, or high-temperature sintering.

Band Engineering Through Pb-Doping of Nanocrystal Building Blocks to Enhance Thermoelectric Performance in Cu3SbSe4.

Developing cost-effective and high-performance thermoelectric (TE) materials to assemble efficient TE devices presents a multitude of challenges and opportunities. Cu3SbSe4 is a promising p-type TE material based on relatively earth abundant elements. However, the challenge lies in its poor electrical conductivity. Herein, an efficient and scalable solution-based approach is developed to synthesize high-quality Cu3SbSe4 nanocrystals doped with Pb at the Sb site. After ligand displacement and annealing treatments, the dried powders are consolidated into dense pellets, and their TE properties are investigated. Pb doping effectively increases the charge carrier concentration, resulting in a significant increase in electrical conductivity, while the Seebeck coefficients remain consistently high. The calculated band structure shows that Pb doping induces band convergence, thereby increasing the effective mass. Furthermore, the large ionic radius of Pb2+ results in the generation of additional point and plane defects and interphases, dramatically enhancing phonon scattering, which significantly decreases the lattice thermal conductivity at high temperatures. Overall, a maximum figure of merit (zTmax) ≈ 0.85 at 653 K is obtained in Cu3Sb0.97Pb0.03Se4. This represents a 1.6-fold increase compared to the undoped sample and exceeds most doped Cu3SbSe4-based materials produced by solid-state, demonstrating advantages of versatility and cost-effectiveness using a solution-based technology.

Precision Interface Engineering of CuNi Alloys by Powder ALD Toward High Thermoelectric Performance

The main bottleneck in obtaining high-performance thermoelectric (TE) materials has been identified as how to decouple the strong interrelationship between electrical and thermal parameters. Herein, we present a precise interface modification approach based on the powder Atomic Layer Deposition (pALD) technology to enhance the performance of CuNi alloys. Single-layer ZnO and Al2O3 layers have been deposited on the surface of powders, typically in 10-100 cycles, and their effect on the TE performance of bulks has been thoroughly investigated. A standard model is proposed and experimentally confirmed to build the relationship between the ALD oxide cycle numbers and Zn and Al content, which could be easily adapted to other pALD processes. The enhancement of the Seebeck coefficient, caused by the energy filtering effect, compensates the electrical conductivity deterioration due to the low electrical conductivity of oxide layers. Furthermore, the oxide layers may significantly increase the phonon scattering. Therefore, to reduce the resistivity of coating layers, a multiple-layer structure is deposited on the surface of powders by inserting Al2O3 into ZnO is constructed on. The atom probe tomography shows that after pressing, the Al atoms diffused into ZnO and realized the doping effect. Al diffusion has the potential to increase the electrical conductivity and complexity of coating layers. In comparison to pure CuNi, zT increased by 227.6% as a result of the decrease in resistivity and stronger phonon scattering in phase boundaries. The study demonstrates that ALD-based interface modification may be a versatile method for decoupling TE parameters and precisely modifying phase boundaries, which is practical for other thermoelectric materials.