Evaluation of efficiency factors and internal resistance of thermoelectric materials

It is well known that the figure of merit (ZT) is unreliable in calculating the efficiency (?) of micro thermoelectric generators system level and unrealistic when comparing the performance of thermoelectric (TE) materials in the same metric units. To solve this problem, we have used COMSOL multiphysics to design a single leg of micro thermoelectric generators model for computing efficiency factors (? ) and internal resistance using TE materials' constants, such as electrical conductivity (σ ), TE conductivity (K ), and Seebeck coefficient (α ). The TE materials were placed between two copper electrodes, and the first data analyzed were the voltages per meter and electric currents per meter. The internal resistances were calculated by taking the ration of voltages to electric currents, and at the same time, the electric powers were calculated from the products of electric currents and voltages yielding power per unit area in μW cm^?2. The ? were calculated using changes in power (ΔP ), temperature gradient (ΔT ), and the surface area (A ). The obtained results showed that the TE materials with highest ? when the temperatures are between 375 and 550 K are n‐type SiGe and p‐type SiGe. When the temperatures are between 550 and 780 K, the TE materials with the highest ? are PbTe‐Pbl₂, PbTe‐CdTe, and PbTe‐SrTe‐Na. We noted that the ? obtained from eight TE materials in this work are within the range as those reported in the literature between 0.001 and 0.091 μW cm^?2 K^?2. The TE materials with high internal resistances such as PbS, PbTe, and PbSe have ? that is <0.0001 μW cm^?2 K^?2, and those with low internal resistances have ? in the range between 0.002 and 0.0091 μW cm^?2 K^?2. This work has shown that COMSOL multiphysics is a powerful computational tool that can be used to analyze internal resistances and ? of TE materials in the same temperature ranges. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of phosphoric acid-doped polybenzimidazole membranes on the performance of H+-ion concentration cell

H⁺-ion concentration cell, which can harvest thermal energy to generate electricity by hydrogen concentration difference principle with a fuel cell structure, is an innovative thermoelectric conversion device. In this system, phosphoric acid-doped polybenzimidazole (PA-doped PBI) membrane is a key component influencing the power generation performance of the cell. Herein, 30, 45, 60, 75, and 90 μm thick PBI membranes are successfully synthesized and doped with phosphoric acid. To achieve a good compromise between the proton conductivity and durability, the properties of PA-doped PBI membranes are experimentally evaluated to clarify the effect of the acid doping time and membrane thickness on cell performance. The results indicate that the higher the acid doping level, the worse the dimensional stability of the membrane. Also the thinner the PBI membrane, the smaller the membrane resistance to ions motion, while the poorer the stability. Upon reaction at 170 °C, this cell can boast a power density from 3.0 to 8.0 W m^?2, which results in a thermoelectric conversion efficiency of 5.97–14.32%. This study potentially boosts the practical application of thermal-to-electrical conversion technology.     

Scaling up self-stratifying supercapacitive microbial fuel cell

Self-stratifying microbial fuel cells with three different electrodes sizes and volumes were operated in supercapacitive mode. As the electrodes size increased, the equivalent series resistance decreased, and the overall power was enhanced (small: ESR = 7.2 Ω and P_max = 13 mW; large: ESR = 4.2 Ω and P_max = 22 mW). Power density referred to cathode geometric surface area and displacement volume of the electrolyte in the reactors. With regards to the electrode wet surface area, the large size electrodes (L-MFC) displayed the lowest power density (460 μW cm⁻²) whilst the small and medium size electrodes (S-MFC, M-MFC) showed higher densities (668 μW cm⁻² and 633 μW cm⁻², respectively). With regard to the volumetric power densities the S-MFC, the M-MFC and the L-MFC had similar values (264 μW mL⁻¹, 265 μW mL⁻¹ and 249 μW cm⁻¹, respectively). Power density normalised in terms of carbon weight utilised for fabricating MFC cathodes-electrodes showed high output for smaller electrode size MFC (5811 μW g⁻¹-C- and 3270 μW g⁻¹-C- for the S-MFC and L-MFC, respectively) due to the fact that electrodes were optimised for MFC operations and not supercapacitive discharges. Apparent capacitance was high at lower current pulses suggesting high faradaic contribution. The electrostatic contribution detected at high current pulses was quite low. The results obtained give rise to important possibilities of performance improvements by optimising the device design and the electrode fabrication.     

Novel hybrid two-stage alkali metal thermoelectric converter and thermally regenerative electrochemical cycle to exploit waste heat of solid oxide fuel cell: Performance assessment and optimization

An innovative combination of a two-stage alkali metal thermoelectric converter (TAMTEC), and thermally regenerative electrical cycle (TREC) is employed to utilize the high-quality heat dissipated from solid oxide fuel cell (SOFC) for further electricity production. The superiority and effectiveness of the SOFC-TAMTEC-TREC system are verified compared to existing SOFC-based hybrid systems and sole SOFC. The performance of the system based on energy, exergy, and economic indicators is evaluated by varying the main design parameters. Parametric assessment demonstrates that the SOFC-TAMTEC-TREC system can reach the maximum power density of 12126 W m^?2 with energy and exergy efficiencies of 47.13% and 50.46% as TAMTEC proportional constant increases to 10^7.5 m² and rising SOFC pore and gain diameters to 3.77 × 10^?6 m and 2.5 × 10^?6 m, respectively reduce the cost rate density of system by 3.55 $ h^?1 m^?2. Furthermore, to achieve the maximum power density and exergy efficiency, and minimum cost rate density, NSGA-III multi-criteria optimization, and decision-making techniques are conducted. Outcomes indicate that Shannon entropy leads to the maximum power density of 8597.2 W m^?2 with a 35.94% enhancement relative to a single SOFC and 1 $ h^?1 m^?2 increment in cost rate density of the hybrid system, while LINMAP and TOPSIS ascertain the minimum increase in the cost rate density by 0.6 $ h^?1 m^?2 with 31.04% improvement in power density relative to single SOFC.     

Improving power density and efficiency of miniature radioisotopic thermoelectric generators

We have built and tested a prototype miniaturized thermoelectric power source that generates 450 μW of electrical power in a system volume of 4.3 cm³. The measured power density of 104 μW cm⁻³ exceeds that of any previously reported thermoelectric power system of equivalent size. This improvement was achieved by implementing a novel thermopile design in which wagon wheel-shaped thermoelectric elements contact the entire circumference of the heat source whereas traditional approaches utilize only one heat source surface. The thermopile consists of 22 wagon wheel-shaped elements (11 P–N thermocouples) fabricated from 215-μm thick bismuth–telluride wafers having ZT = 0.97 at 30 °C. The power source operates on a 150 mW thermal input provided by an electrical resistance heater that simulates a capsule containing 0.4 g of ²³⁸PuO₂ located at the center of the device. Our primary research objective was to develop and demonstrate a prototype thermopile and radioisotopic thermoelectric generator (RTG) architecture with improved power density at small scales. Output power from this device, while optimized for efficiency, was not optimized for output voltage, and the maximum power was delivered at 41 mV. We also discuss modifications to our prototype design that result in significantly improved voltage and power. Numerical predictions show that a power output of 1.4 mW, power density of 329 μW cm⁻³, and voltage of 362 mV, is possible in the same package size.     

A novel composite oxygen electrode: PrBaCo2O5+δ combined with negative thermal expansion oxide applied to reversible solid oxide cells

The thermal expansion coefficient (TEC) of Co-based layered perovskite electrodes is about twice than that of common electrolytes, and this thermal mismatch between electrode and electrolyte leads to the delamination and cracking of electrode. To solve this problem thoroughly, a strategy of introducing negative thermal expansion (NTE) material is proposed. The average linear thermal expansion coefficient of PrBaCo₂O_5+δ (PBC) decreases significantly from 22.3 × 10^?6 K^?1 to 12.2 × 10^?6 K^?1 when compounds with 50 wt% NdMnO_3-δ (NM). The results of multi physical field coupling calculation show that the introduction of NTE oxide can reduce the residual stress of oxygen electrodes and electrolytes, which decreases the trend of electrodes damaged by thermal stress. The composite electrode (PBC-NM) shows excellent electrocatalytic activities and reversible cycle performance. The peak power densities (PPDs) of the cell with PBC decreases from 1.4 to 0.48 W cm^?2 (65.7% decrease) after 20 thermal cycles, while the one of PBC-NM-based cell decreases from 1.55 to 1.25 W cm^?2 (19.4% decrease). Electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) and distribution of relaxation time (DRT) analysis show that the improvement of thermal cycle stability of SOFC can be attributed to the ideal thermal matching between electrolyte and oxygen electrode.     

Quantitative analysis of proton exchange membrane prepared by radiation-induced grafting on ultra-thin FEP film

Radiation-induced graft polymerization is introduced to effectively fabricate proton exchange membrane based on 12.5 μm fluorinated ethylene propylene (FEP) film. The graft side chains penetrate FEP film and distribute inside the bulk matrix evenly. The membranes exhibit hydrophilic/hydrophobic microphase-separated morphology as well as good thermal stability. The influences of irradiation parameters on the membrane property are investigated and the resulting membranes (named FEP-g-PSSA) exhibit excellent physicochemical properties. Membrane with 27.48% degree of graft and 130.1 mS cm^?1 proton conductivity is employed for fuel cell performance measurement. Under optimized operate conditions (80 °C, 75% relative humidity), the power density could reach up to 0.896 W cm^?2, inspiring for fuel cell application. The mass-transport-controlled polarization of membrane electrode assembly (MEA) based on FEP-g-PSSA membrane is higher than Nafion® 211 within the whole current density range and the gap is widening with increasing current density. At 2.0 A cm^?2, the mass transfer polarization of FEP-g-PSSA reaches up to 0.204 V, far higher than Nafion® 211 (0.084 V). By promoting the compatibility between the ionomer in the catalyst layer and FEP-g-PSSA membrane and optimizing the membrane/catalyst layer/gas diffusion layer interfaces, the fuel cell performance could be significantly enhanced, making the FEP-g-PSSA membranes promising in fuel cell application.     

Feasibility of using thin polybenzimidazole electrolytes in high-temperature proton exchange membrane fuel cells

The use of thin polybenzimidazole membranes in high-temperature polymer electrolyte membrane fuel cells is explored. Membranes in thickness of 10–40 μm are prepared, doped and characterized, including fuel cell test. High molecular weight polymers enable fabrication of membranes as thin as 10 μm with sufficient mechanical strength. The thin membranes, upon acid doping, exhibit comparable conductivity and hence decreased ohmic resistance. Membrane electrode assemblies with thin membranes down to 10 μm show slightly lower open-circuit voltages than that for reference 40 μm but all above 0.97 V. This is in good agreement with the hydrogen permeability measurements, which show a value around 10^?12 mol cm^?1 s^?1 bar^?1, corresponding to a crossover current density of <1 mA cm^?2. The acid transferred from the membrane to the catalyst layer seems constant, as the iR-free polarization plots are nearly the same for membranes of varied thicknesses. The acid remaining in the membrane after the break-in period is estimated, showing an acid inventory issue when thin membranes are used. This is verified by using the membranes of higher acid doping levels.     

Facile preparation of SnS2 nanoflowers and nanoplates for the application of high-performance hybrid supercapacitors

In this work, the SnS₂ nanoflowers (SnS₂ NFs) were solvothermally prepared in the solvent of ethanol, while SnS₂ nanoplates (SnS₂ NPs) were obtained through the identical conditions except for the solvent of water. The flowers were assembled with numerous nanosheets with very thin thickness, and the NPs exhibited hexagonal shape. When used as the battery-type electrode material for supercapacitors, the SnS₂ NFs delivered a specific capacity of as high as 264.4 C g^?1 at 1 A g^?1, which was higher than the 201.6 C g^?1 of SnS₂ NPs. Furthermore, a hybrid supercapacitor (HSC) was assembled with the SnS₂ as positive electrode and activated carbon (AC) as negative electrode, respectively. The SnS₂ NFs//AC HSC exhibited a high energy density of 28.1 Wh kg^?1 at 904.3 W kg^?1, which was higher than the 24.2 Wh kg^?1 at 844.3 W kg^?1 of SnS₂ NPs//AC HSC. Especially, when the power density was enhanced to the highest value of 8666.8 W kg^?1, the NFs-based device could still hold 20.4 Wh kg^?1. In addition, both HSC devices showed an excellent cycling stability after 5000 cycles at 5 A g^?1. The present method is simple and can be extended to the preparation of other transition metal sulfides (TMSs)-based electrode materials with brilliant electrochemical performance for supercapacitors.     

Microwave sintering of high-performance BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) electrolytes for intermediate-temperature solid oxide fuel cells

As a promising electrolyte material for solid oxide fuel cells (SOFCs), BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3-δ (BZCYYb) often surfers from its high sintering temperature, which causes Ba evaporation and sluggish grain growth, thus reducing the electrical conductivity. In this work, densified BZCYYb electrolytes were fabricated at temperatures as low as 1400 °C using the microwave sintering technique. Comparing with the conventional sintered ones, a temperature decrease of 150 °C is achieved. The Ba evaporation is effectively suppressed, and large grain sizes of ～4 μm are obtained. The total conductivity for microwave sintered symmetric cell measured in wet air at 700 °C is 3.8 × 10^?2 S cm^?1, benefiting from both enhanced bulk conductivities by 1–2 times and grain boundary conductivities by 50 times. With the microwave sintered BZCYYb as electrolyte, an anode-supported cell reaches a maximum power density of 0.64 W cm^?2 at 700 °C.     

Chicken nuggets-like core/shell nanosheet arrays as high performance flexible all-solid-state supercapacitor cathode and buckwheat shell as anode

The energy density of a flexible all-solid-state supercapacitor (ASC) requires new electrode material with special structure and morphology as a prerequisite for its secured improvement. In this paper, a new morphological exploration of chicken nuggets-like core/shell NiCo₂O₄/MnO₂ (NCM) nanosheet arrays on Ni foam was employed. The application of this special morphology aims to greatly improve the electrochemical performance of the cathode electrode. Additionally, Buckwheat Biochar (BBC) is utilized as the anode while the PVA/KOH thin film is prepared as the separator. The chicken nuggets-like core/shell NCM nanosheet arrays were obtained by a two-step hydrothermal method. A series of characterization methods were carried out to further support the core/shell's well-designed structure and precise composition. The tests exhibited excellent specific capacitance of 593.3 F g^?1 at 5 mA cm^?2 and outstanding cycling stability with a retention of 90% after 10000 cycles. Furthermore, the assembled NCM//BBC ASC device indicated a high specific capacitance (239 F g^?1 at the current density of 5 mA cm^?2), this is in due part of the unique architecture of NCM nanosheet arrays and interconnected special porous structure of the BBC and the thin film PVA/KOH. Hence, the assembled ASC device exhibited high energy density (an energy density of 58 Wh·kg^?1 at 3263 W kg^?1) and remarkable cycling stability.     

Enhanced electricity production in single-chamber MFCs with air cathodes decorated by Fe–N–C catalysts derived from 5H-dibenz [b,f] azepine-5-carboxamide (Carbamazepine)

For practical applications of microbial fuel cells (MFCs), 5H-dibenz [b,f] azepine-5-carboxamide (Carbamazepine, CBZ) was used as the organic precursor for the synthesis of catalysts composed of Fe–N–C complexes (named as Fe-CBZ-Cats) through a sacrificial support method. Characterizations by SEM, XPS and TEM-EDS elemental mapping show that the synthesized Fe-CBZ-Cats have porous structure and uniformly dispersed Fe/N/C complex centers which could play key roles in effective ORR. Linear scanning voltammetry (LSV) measurements show that the synthesized Fe-CBZ-Cats exhibits ORR activity comparable to commercial Pt/C catalysts under the same catalyst loading (2 mg cm⁻²). The maximum power density produced by cathode-limiting MFCs with Fe-CBZ-Cats air cathodes was 431 ± 23 μW cm⁻², higher than those in the control MFCs with Pt/C air cathodes (403 ± 13 μW cm⁻²) and activated carbon air cathodes (296 ± 24 μW cm⁻²). In addition, the toxicity tolerance of the synthesized Fe-CBZ-Cats is much higher than Pt/C.     

Control of self-organization of drop-casted Nafion film for improving proton conduction in a polymer-electrolyte-membrane fuel cell to raise its output power density

A simple drop-cast method to directly deposit Nafion polymer electrolyte membrane (PEM) on nanostructured thin-film catalyst layer composed of stacked Pt nanoparticles prepared by pulsed laser deposition (PLD) was demonstrated. Through optimization of solvent composition and drying temperature of Nafion solution to control self-organization of Nafion, a uniform PEM with better bulk and interface microstructures could be produced, leading to a significant improvement in the output current density of a PEM fuel cell over that using reference commercial PEMs. The formation of facile proton conduction pathways in the bulk Nafion membrane resulted in a 35% reduction in ohmic resistance compared to that with the commercial membrane. Moreover, the infiltration of Nafion in the catalyst layer formed suitable proton transport network to render more catalyst nanoparticles effective and thus lower charge-transfer resistance. With the optimized PLD, drop-cast, and hot-pressing conditions, the current density of PEMFCs using drop-casted PEM reached 1902 mA cm⁻² at 0.6 V at 2 atm H₂ and O₂ pressures with a cathode Pt loading of 100 μg cm⁻², corresponding to a power density of 1.14 W cm⁻² and a cathode mass-specific power density of 11.4 kW g⁻¹.     

A novel hybrid ammonia fuel cell and thermal energy storage system

In this paper, we develop and experimentally investigate a novel hybrid ammonia fuel cell and thermal energy storage system. A molten alkaline salt is utilized for storing thermal energy as well as operating an alkaline electrolyte‐based direct ammonia fuel cell. The specific thermal energy storage capacity of the hybrid system is found to be 133 kJ kg^?1 at a temperature of 320°C. Furthermore, the maximum power densities are found to be 2.1±0.1 W m^?2 to 2.3±0.1 W m^?2 for operating temperatures varying between 220°C and 320°C. The energy efficiency is evaluated as 20.6±0.6%, and the exergy efficiency is determined to be 23.3±0.7% at the peak power density.     

Integration of molten carbonate fuel cell and looped multi-stage thermoacoustically-driven cryocooler for electricity and cooling cogeneration

Thermal management is essential for high-temperature molten carbonate fuel cell (MCFC) because the accumulated waste heat may degrade the durability. In this paper, looped multi-stage thermoacoustically-driven cryocooler (LMTC) is proposed to reuse the waste heat from MCFC for cooling production, which not only can tackle with the thermal management issue but also can provide additional usages. Accounting various irreversible dissipation, the models of MCFC, LMTC and MCFC-LMTC hybrid system are analytically formulated. Performance features of MCFC-LMTC hybrid system are revealed and the advantages are expounded via calculation examples. Calculations indicate that the maximum power density and corresponding efficiency of the hybrid system are 1688.9 W m^?2 and 39.7%, which are 11.4% and 1.3% bigger than that of the sole MCFC system, respectively. By comparing with other available systems, the superiority of using LMTC to recover MCFC waste heat for refrigeration is clearly demonstrated. Considerable parametric studies show that the heat-transfer coefficient of hot heat exchange for LMTC is not suggested to be greater than 2.5 × 10^?3 W m^?2 K^?1. In addition, an increase in the working temperature, working pressure of MCFC, reactant concentration or engine stage number of LMTC positively benefits the hybrid system performance, while an increase in the thermodynamic loss coefficient worsens the hybrid system performance. The obtained results may offer new insights into improving the performance of MCFCs through thermal management approaches.     

Surface polar charge induced Ni loaded CdS heterostructure nanorod for efficient photo-catalytic hydrogen evolution

Designing of artificial heterostructure photo-catalysts to crop solar energy for H₂ evolution from water is of great importance nowadays. The ultrafine Ni (0.5, 1.0, 2.0 and 5.0 wt%) particles loaded CdS nanorods were synthesized by a simple chemical process. XRD shows the crystalline phase of CdS with increase in size from 17 to 28 nm with 10.19% and 10.06% enhancement in the lattice strain and the dislocation density for Ni (0.5–5.0 wt%). The XPS peaks observed at 854.88 eV and 861.07 eV for Ni²⁺ with energy separation of 6.18 eV confirmed the existence of NiO on Ni surface. The Raman bands for pure CdS and Ni (1.0 wt%)-CdS nanorods were observed at 300 cm^?1 and 293 cm^?1 for 1LO phonon and 601 cm^?1 and 586 cm^?1 for 2LO phonon, respectively. The Ni loading tuned the CdS band gap from 2.36 to 2.20 eV. The eight fold enhancement in the CdS specific surface area i.e., from 4.19194 m² g^?1 to 34.8343 m² g^?1 was achieved. After Ni loading, the synergetic effect of efficient electron separation and transportation was observed by the continuous quenching of luminescence emission intensity and the reduction of charge transfer resistance from 706 Ω for CdS to 484 Ω of CdS. The Ni (1.0 wt%)@ NiO optimal loading on CdS results highest photo-catalytic H₂ evolution of 9.0 mmol at rate of 1.8 mmol h^?1, which is about 50 times higher than that of 180 μmol at rate of 36 μmol h^?1 for pure CdS. A thin layer of NiO on plasmonic Ni surface could be the promising system for photo-catalytic H₂ evolution due to visible light photo-activity.     

Optimized thermal coupling of micro thermoelectric generators for improved output performance

There is a significant push to increase the output power of thermoelectric generators (TEGs) in order to make them more competitive energy harvesters. The thermal coupling of TEGs has a major impact on the effective temperature gradient across the generator and therefore the power output achieved. The application of micro fluidic heat transfer systems (μHTS) can significantly reduce the thermal contact resistance and thus enhance the TEG's performance. This paper reports on the characterization and optimization of a μTEG integrated with a two layer μHTS. The main advantage of the presented system is the combination of very low heat transfer resistances with small pumping powers in a compact volume. The influence of the most relevant system parameters, i.e. microchannel width, applied flow rate and the μTEG thickness on the system's net output performance are investigated. The dimensions of the μHTS/μTEG system can be optimized for specific temperature application ranges, and the maximum net power can be tracked by adjusting the heat transfer resistance during operation. A system net output power of 126 mW/cm² was achieved with a module ZT of 0.1 at a fluid flow rate of 0.07 l/min and an applied temperature difference of 95K.It was concluded that for systems with good thermal coupling, the thermoelectric material optimization should focus more on the power factor than on the figure of merit ZT itself, since the influence of the thermal resistance of the TE material is negligible.     

Fiber-based flexible thermoelectric power generator

Flexible thermoelectric power generators fabricated by evaporating thin films on flexible fiber substrates are demonstrated to be feasible candidates for waste heat recovery. An open circuit voltage of 19.6 μV K per thermocouple junction is measured for Ni–Ag thin films, and a maximum power of 2 nW for 7 couples at ΔT = 6.6 K is measured. Heat transfer analysis is used to project performance for several other material systems, with a predicted power output of 1 μW per couple for Bi₂Te₃/Sb₂Te₃-based fiber coatings with a hot junction temperature of 100 °C. Considering the performance of woven thermoelectric cloths or fiber composites, relevant properties and dimensions of individual thermoelectric fibers are optimized.     

Low temperature solid oxide fuel cells with pulsed laser deposited bi-layer electrolyte

Solid oxide fuel cells (SOFC) using a pulsed laser deposited bi-layer electrolyte have been successfully fabricated and have shown very good performance at low operating temperatures. The cell reaches power densities of 0.5 W cm⁻² at 550 °C and 0.9 W cm⁻² at 600 °C, with open circuit voltage (OCV) values larger than 1.04 V. The bi-layer electrolyte contains a 6–7 μm thick samarium-doped ceria (SDC) layer deposited over a ∼1 μm thick scandium-stabilized zirconia (ScSZ) layer. The electrical leaking between the anode and cathode through the SDC electrolyte, which due to the reduction of Ce⁴⁺ to Ce³⁺ in reducing environment when using a single layer SDC electrolyte, has been eliminated by adopting the bi-layer electrolyte concept. Both ScSZ and SDC layers in the bi-layer electrolyte prepared by the pulsed laser deposition (PLD) technique are the highly conductive cubic phases. Poor conductive (Zr, Ce)O₂-based solid solutions or β-phase ScSZ were not found in the bi-layer electrolyte prepared by the PLD due to low processing temperatures of the technique. Excellent reliability and flexibility of the PLD technique makes it a very promising technique for the fabrication of thin electrolyte layer for SOFCs operating at reduced temperatures.     

Preparation of Pr2NiO4+δ-La0.6Sr0.4CoO3-δ as a high-performance cathode material for SOFC by an impregnation method

As a Ruddlesden-Popper (RP) phase solid oxide fuel cell (SOFC) cathode material, Pr₂NiO_4+δ (PNO) is a critical challenge for SOFC commercialization due to the lack of oxygen vacancies and insufficient redox reaction (ORR) activity. In this paper, various concentrations of La_0.6Sr_0.4CoO_3-δ (LSC) nanoparticles are coated on the surface of PNO by an impregnation method, and the ORR kinetics of PNO is found to be improved by constructing a composite cathode with heterointerfaces. The formation of the heterointerface effectively enhances the transfer of interstitial oxygen in the PNO and the oxygen vacancies in LSC, which can promote the conduction of O^2? in the cathode and thus improves the ORR activity of the material. When the impregnation concentration of LSC reached C_LSC = 0.2 mol L^?1, the ORR activity can reach the highest level. At 700 °C, the area-specific resistance of PNO-LSC reaches 0.024 Ω cm², which is 83.4% lower than that of PNO (0.145 Ω cm²). And the peak power density of PNO-LSC reaches 0.618 W cm^?2, which is 1.89 times larger than that of PNO (0.327 W cm^?2). Therefore, the construction of composite cathodes with heterointerfaces via impregnation provides an alternative strategy for enhancing the ORR activity of the cathode materials in SOFC.