Highly Active FeCoNiCuMn High-entropy Alloys/Carbon Cloth Composite: Synthesis and Its Performance in Thermo-electrochemical Cells

doi:10.15541/jim20260030

Abstract

Abstract:

Thermo-electrochemical cells (TECs) are a new type of system for harvesting low-grade waste heat. Their development and utilization can contribute to improving overall energy efficiency and mitigating the urban heat island effect. Metallic platinum (Pt), a commonly used electrode material in TEC research, is costly, which significantly limits the widespread application of TECs. Therefore, developing low-cost, high-performance alternative electrodes has become a research hotspot in the field of TECs. In this study, commercial carbon cloth (CC) was used as both the substrate and structural directing agent. Then, catalytically active FeCoNiCuMn high-entropy alloys (HEAs) nanoparticles were uniformly grown onto CC, forming a FeCoNiCuMn HEAs/CC composite used as an electrode material for TECs. The high-entropy effect of HEAs endows the composite with the stable chemical structure, while the interaction among its multiple principal elements enhances its catalytic activity and reaction kinetics. Thus, the FeCoNiCuMn HEAs/CC electrode possesses a higher electrochemical active surface area (2.52 cm²) and a lower charge transfer resistance (2 Ω) compared to CC, the ternary FeCoNi/CC, and the quaternary FeCoNiCu/CC. Furthermore, the HEAs/CC-based TECs achieve a current density of 0.35 mA·cm^-2 and an output power density of 30.40 mW·m^-2 under a temperature difference of 22.0 K, significantly higher than those achieved by TECs using CC (0.17 mA·cm^-2/14.55 mW·m^-2), FeCoNi/CC (0.27 mA·cm^-2/19.00 mW·m^-2), and FeCoNiCu/CC (0.30 mA·cm^-2/24.44 mW·m^-2) as electrodes under the same conditions. Additionally, the cell system maintains 91.5% of its initial short-circuit current after 7 d of cycling and also exhibits good reversibility. The highly active FeCoNiCuMn HEAs/CC composite constructed in this study provides a promising pathway for the development and application of low-cost, high-performance TECs electrode materials.

Key words: low-grade waste heat harvesting, thermo-electrochemical cell, electrode material, high-entropy alloy

CLC Number:

TQ174

ZHU Mengting, ZHANG Ruifeng, QIAO Zihan, MA Ruguang, WU Zhengying. Highly Active FeCoNiCuMn High-entropy Alloys/Carbon Cloth Composite: Synthesis and Its Performance in Thermo-electrochemical Cells[J]. Journal of Inorganic Materials, 2026, 41(10): 1387-1395.

Figures/Tables 11

Fig. 1 Schematic illustration, SEM and TEM characterizations of HEAs/CC (a) Schematic illustration for the formation of HEAs/CC; SEM images of (b, c) HEAs/CC As and (d) HEAs/CC; (e) TEM image with inset showing the particle size distribution; (f, g) HRTEM images with insets in (f) showing fast Fourier transform (FFT) images of HEAs/CC; (h) EDS elemental mappings of Fe, Co, Ni, Cu, and Mn elements

Fig. 2 XRD and XPS results of HEAs/CC (a) XRD patterns of HEAs/CC As and HEAs/CC; (b) Magnified XRD pattern of HEAs/CC; (c) Survey, (d) C1s, (e) Fe2p, (f) Co2p, (g) Ni2p, (h) Cu2p, and (i) Mn2p XPS spectra of HEAs/CC. Colorful figures are available on website

Fig. 3 Electrochemical performance of CC, FeCoNi/CC, FeCoNiCu/CC and HEAs/CC CV curves of (a) FeCoNi/CC, (b) FeCoNiCu/CC, and (c) HEAs/CC under different scan rates; (d) Fitting lines of peak current vs. v1/2; (e) CV curves at a scan rate of 10 mV·s-1; (f) ESA histogram; (g) LSV curves; (h) EIS spectra and (i) magnified area

Fig. 4 Schematic diagram of TECs

Fig. 5 Thermo-electrochemical performance of CC, FeCoNi/CC, FeCoNiCu/CC and HEAs/CC (a) VOC-ΔT curves and histogram of Se; (b) ISC-ΔT fitting lines; (c) Pmax-ΔT curves; (d-g) JSC-V and P-V curves; (h) Cycling performance; (i) Reversibility in the ΔT range from 4.0 K to 20.8 K. Colorful figures are available on website

Fig. 6 Stability of HEAs/CC-TECs for over 7 d at ΔT=13.0 K Colorful figure is available on website

Fig. S1 (a) Schematic diagram and (b) physical photo of the TECs device[S2]

Fig. S2 Comparison of thermo-electrochemical performance of TEC systems with HEAs/CC and Pt as electrodes (a) ISC-ΔT fitting lines; (b) Pmax-ΔT curves; (c, d) JSC-V and P-V curves

Fig. S3 SEM characterizations of HEAs/CC after the 7-day cycles (a, b) SEM images of HEAs/CC; (c) Magnified SEM image in the yellow line frame of (a); (d) EDS elemental mappings of Fe, Co, Ni, Cu, and Mn elements

Fig. S4 XPS survey spectra of HEAs/CC before and after the 7-day cycles

Fig. S5 High-resolution XPS spectra of HEAs/CC before and after the 7-day cycles (a) C1s; (b) Fe2p; (c) Co2p; (d) Ni2p; (e) Cu2p; (f) Mn2p

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