Mn-doping induced phase segregation of air electrodes enables high-performance and durable reversible protonic ceramic cells

doi:10.1016/S1872-2067(25)64907-2

Abstract

Abstract:

Reversible protonic ceramic cells (R-PCCs) represent a highly promising energy conversion and storage technology, offering high efficiency at intermediate temperatures (400-700 °C). However, their commercialization is significantly impeded by the sluggish oxygen reaction kinetics on air electrodes. This work reports a Mn-doped PrBa_0.8Ca_0.2Co₂O₅₊_δ air electrode with a nominal composition of PrBa_0.8Ca_0.2Co_1.5Mn_0.5O₅₊_δ, which primarily segregates into a deficient double perovskite Pr_1.25Ba_0.5Ca_0.25Co_1.58Mn_0.42O₅₊_δ phase and a minor BaCo_0.6Mn_0.4O₃_-δ hexagonal perovskite phase, as suggested by the X-ray diffraction refinement. The formation of Mn-doped nanocomposites substantially enhances the activities of oxygen reduction/evolution reactions, attributed to elevated oxygen vacancy concentrations and improved oxygen surface exchange and bulk diffusion capabilities, relative to the undoped PrBa_0.8Ca_0.2Co₂O₅₊_δ. The synergistic effect between the two phases may enhance electrochemical performance. Single cells incorporating these nanocomposite air electrodes achieve exceptional electrochemical performance at 700 °C: peak power density of 2.05 W cm^-2 in fuel cell (FC) mode and current density of -3.78 A cm^-2 at 1.3 V in electrolysis (EL) mode. Furthermore, promising durability is demonstrated during a FC test (100 h), an EL test (100 h), and a FC-EL cycling test (120 h) at 600 °C. This Mn-doping approach establishes an effective strategy for developing advanced air electrode materials.

Key words: Reversible protonic ceramic cells, Air electrodes, Mn-doping, Oxygen reduction reactions, Oxygen evolution reaction

Xiaofeng Chen, Yixuan Huang, Wanbin Lin, Jiaojiao Xia, Xirui Zhang, Wenjie Gong, Chuqian Jian, Hao Liu, Jiacheng Zeng, Jiang Liu, Yu Chen. Mn-doping induced phase segregation of air electrodes enables high-performance and durable reversible protonic ceramic cells[J]. Chinese Journal of Catalysis, 2026, 81: 333-343.

×
share this article

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(25)64907-2

https://www.cjcatal.com/EN/Y2026/V81/I2/333

Figures/Tables 4

Fig. 1. Phase and microstructure analyses of the PBCCMx powder. (a) XRD patterns of PBCC and PBCCMx (x = 0.1, 0.3, 0.4, 0.5, 0.6, 1.0, 1.5) powders. (b) Rietveld refinement profile of the PBCCM0.5 sample. (c) High-resolution TEM images showing a D-PBCCMn grain and a BaCo0.6Mn0.4O3-δ grain. (d) STEM-EDS elemental mapping images of PBCCM0.5 powder.

Fig. 2. Electrochemical performance of electrodes. (a) EIS curves of PBCCM0.5 air electrodes measured in wet air (3% H2O) from 500 to 700 °C. (b) ASR comparison of air electrodes with distinct Mn doping levels (0, 0.1, 0.3, 0.4, 0.5, 0.6, 1.0 and 1.5) at 550, 600, and 650 °C in humidified air (3% H2O). (c) ASR comparison between PBCCM0.5 and reference air electrodes in BZCYYb-based symmetrical cells from 500 to 700 °C. (d) EIS data of PBCCM0.5 electrodes at 600 °C under varying pO2 conditions. (e) Corresponding DRT plots for PBCCM0.5 electrodes under different pO2 at 600 °C. (f) Rp dependence of PBCCM0.5 electrodes on pO2 at 600 °C. (g) EIS data of PBCCM0.5 electrodes at 600 °C under varying pH2O conditions. (h) Corresponding DRT plots for PBCCM0.5 electrodes under different pH2O at 600 °C; (i) Rp dependence of PBCCM0.5 electrodes on pH2O at 600 °C.

Fig. 3. Origin of the performance enhancement. (a) Temperature-dependent ASRs for symmetrical cells employing PBCCM0.5 electrodes and physically mixed electrodes (D-PBCCMn and BCMO). (b) Comparative ASR stability of PBCCM0.5, PBCC, BCMO electrodes and physically mixed electrodes (D-PBCCMn and BCMO) in symmetrical cells. (c) DRT analysis of PBCCM0.5, PBCC, BCMO electrodes, and physically mixed electrodes (D-PBCCMn and BCMO) recorded at different measurement times. (d) Derived k*chem and D*chem values for PBCCM0.5 and PBCC materials between 550 and 700 °C. (e) O 1s XPS spectra of PBCCM0.5 and PBCC powder samples. (f) Distribution of oxygen species in PBCCM0.5 and PBCC powders (histogram representation).

Fig. 4. Single cell performance. (a) I-V-P curves of R-PCCs equipped with PBCCM0.5 air electrodes operating in FC mode across 500-700 °C. (b) Performance comparison of PPDs among other electrode materials reported recently (Table S5). (c) Cross-sectional SEM image depicting the PBCCM0.5 air electrode interface within a single-cell assembly. (d) I-V curves of R-PCCs featuring PBCCM0.5 air electrodes in EL mode across 500-700 °C. (e) Evaluation of electrolysis current densities at 1.3 V for various electrode materials (Table S6). (f) Faradaic efficiency measurements under varying current densities and water vapor concentrations. (g) Short-term stability assessment of R-PCCs with PBCCM0.5 in FC mode at 600 °C. (h) EL mode stability analysis of R-PCCs with PBCCM0.5 at 600 °C. (i) Stability evaluation of R-PCCs with PBCCM0.5 during cyclic reversible mode.

References

[1]	J. Cao, Y. Ji, Z. Shao, Energy Environ. Sci., 2022, 15, 2200-2232.
[2]	H. I. Karunadasa, C. J. Chang, J. R. Long, Nature, 2010, 464, 1329-1333.
[3]	N. S. Lewis, D. G. Nocera, Proc. Natl. Acad. Sci. U. S. A., 2007, 104, 20142-20142.
[4]	Y. Chen, S. Ji, C. Chen, Q. Peng, D. Wang, Y. Li, Joule, 2018, 2, 1242-1264.
[5]	X. Chen, N. Yu, Y. Song, T. Liu, H. Xu, D. Guan, Z. Li, W.-H. Huang, Z. Shao, F. Ciucci, M. Ni, Adv. Mater., 2024, 36, 2403998.
[6]	S. Choi, C. J. Kucharczyk, Y. Liang, X. Zhang, I. Takeuchi, H.-I. Ji, S. M. Haile, Nat. Energy, 2018, 3, 202-210.
[7]	J.-H. Myung, D. Neagu, D. N. Miller, J. T. S. Irvine, Nature, 2016, 537, 528-531.
[8]	Y. Xu, K. Xu, F. Zhu, F. He, H. Zhang, C. Fang, Y. Liu, Y. Zhou, Y. Choi, Y. Chen, ACS Energy Lett., 2023, 8, 4145-4155.
[9]	Y. Xu, K. Xu, H. Zhang, F. Zhu, F. He, Y. Liu, Y. Chen, Sci. Bull., 2024, 69, 3682-3691.
[10]	J. Yun, H. Shin, S. Kim, B. Seong, S. Lee, K. Kim, S. H. Choi, S. Choi, Adv. Funct. Mater., 2025, DOI:10.1002/adfm.202508758.
[11]	C. Zhang, Nat. Energy, 2016, 1, 16064.
[12]	F. Liu, H. Deng, D. Diercks, P. Kumar, M. H. A. Jabbar, C. Gumeci, Y. Furuya, N. Dale, T. Oku, M. Usuda, P. Kazempoor, L. Fang, D. Chen, B. Liu, C. Duan, Nat. Energy, 2023, 8, 1145-1157.
[13]	W. Bian, W. Wu, B. Wang, W. Tang, M. Zhou, C. Jin, H. Ding, W. Fan, Y. Dong, J. Li, D. Ding, Nature, 2022, 604, 479-485.
[14]	Y. Wang, Y. Ling, B. Wang, G. Zhai, G. Yang, Z. Shao, R. Xiao, T. Li, Energy Environ. Sci., 2023, 16, 5721-5770.
[15]	X. Zhang, C. Tang, Y. Yang, F. Zheng, Q. Su, H. Xiang, L. Meng, L. Du, Y. Aoki, D. Luo, N. Wang, S. Ye, Adv. Funct. Mater., 2025, 35, 2421083.
[16]	C. Duan, R. Kee, H. Zhu, N. Sullivan, L. Zhu, L. Bian, D. Jennings, R. O’Hayre, Nat. Energy, 2019, 4, 230-240.
[17]	Y. Zhang, B. Chen, D. Guan, M. Xu, R. Ran, M. Ni, W. Zhou, R. O’Hayre, Z. Shao, Nature, 2021, 591, 246-251.
[18]	F. He, Y. Zhou, T. Hu, Y. Xu, M. Hou, F. Zhu, D. Liu, H. Zhang, K. Xu, M. Liu, Y. Chen, Adv. Mater., 2023, 35, 2209469.
[19]	Y. Niu, Y. Zhou, W. Zhang, Y. Zhang, C. Evans, Z. Luo, N. Kane, Y. Ding, Y. Chen, X. Guo, W. Lv, M. Liu, Adv. Energy Mater., 2022, 12, 2103783.
[20]	M. Liang, Y. Song, Y. Song, D. Guan, D. Liu, W. Li, I. V. Alexandrov, A. V. Sidelnikov, G. Yang, W. Zhou, R. Ran, M. Xu, Z. Shao, Adv. Funct. Mater., 2025, 2507790.
[21]	S. Zheng, W. Wu, Y. Zhang, Z. Zhao, C. Duan, S. Karki, H. Ding, Nat. Commun., 2025, 16, 4146.
[22]	Z. Liu, Y. Lin, H. Nie, D. Liu, Y. Li, X. Zhao, T. Li, G. Yang, Y. Sun, Y. Zhu, W. Wang, R. Ran, W. Zhou, Z. Shao, Adv. Funct. Mater., 2024, 34, 2311140.
[23]	Y. Zhang, R. Knibbe, J. Sunarso, Y. Zhong, W. Zhou, Z. Shao, Z. Zhu, Adv. Mater., 2017, 29, 1770345.
[24]	C. Xia, Solid State Ion., 2002, 149, 11-19.
[25]	A. Esquirol, N. P. Brandon, J. A. Kilner, M. Mogensen, J. Electrochem. Soc., 2004, 151, A1847-A1855.
[26]	Z. Shao, S. M. Haile, Nature, 2004, 431, 170-173.
[27]	Y. Song, J. Liu, Y. Wang, D. Guan, A. Seong, M. Liang, M. J. Robson, X. Xiong, Z. Zhang, G. Kim, Z. Shao, F. Ciucci, Adv. Energy Mater., 2021, 11, 2101899.
[28]	M. Liang, Y. Song, D. Liu, L. Xu, M. Xu, G. Yang, W. Wang, W. Zhou, R. Ran, Z. Shao, Appl. Catal. B, 2022, 318, 121868.
[29]	Y. Chen, S. Yoo, Y. Choi, J. H. Kim, Y. Ding, K. Pei, R. Murphy, Y. Zhang, B. Zhao, W. Zhang, H. Chen, Y. Chen, W. Yuan, C. Yang, M. Liu, Energy Environ. Sci., 2018, 11, 2458-2466.
[30]	C. Duan, J. Tong, M. Shang, S. Nikodemski, M. Sanders, S. Ricote, A. Almansoori, R. O’Hayre, Science, 2015, 349, 1321-1326.
[31]	C. Lim, S. Sengodan, D. Jeong, J. Shin, G. Kim, Int. J. Hydrogen Energy, 2019, 44, 1088-1095.
[32]	Z. Du, F. He, H. Gao, Y. Xu, F. Zhu, K. Xu, J. Xia, H. Zhang, Y. Huang, Y. Liu, Y. Chen, Energy Storage Mater., 2024, 68, 103345.
[33]	A. B. Muñoz-García, M. Tuccillo, M. Pavone, J. Mater. Chem. A, 2017, 5, 11825-11833.
[34]	J. Van Herle, R. Vasquez, J. Eur. Ceram. Soc., 2004, 24, 1177-1180.
[35]	S. J. Heo, S. P. Harvey, A. G. Norman, M. A. Rahman, P. Singh, A. Zakutayev, ACS Appl. Mater. Interfaces, 2024, 16, 11646-11655.
[36]	N. Wang, S. Hinokuma, T. Ina, H. Toriumi, M. Katayama, Y. Inada, C. Zhu, H. Habazaki, Y. Aoki, Chem. Mater., 2019, 31, 8383-8393.
[37]	J. Kim, S. Choi, S. Park, C. Kim, J. Shin, G. Kim, Electrochim. Acta, 2013, 112, 712-718.
[38]	Z. W. Du, K. Xu, F. Zhu, Y. S. Xu, F. He, H. Gao, W. J. Gong, Y. Choi, Y. Chen, Adv. Funct. Mater., 2024, 34, 2409188.
[39]	A. Olszewska, Z. Du, K. Świerczek, H. Zhao, B. Dabrowski, J. Mater. Chem. A, 2018, 6, 13271-13285.
[40]	L. Yang, S. Z. Wang, K. Blinn, M. F. Liu, Z. Liu, Z. Cheng, M. L. Liu, Science, 2009, 326, 126-129.
[41]	H. Zhang, Y. C. Zhou, K. Pei, Y. X. Pan, K. Xu, Y. Ding, B. T. Zhao, K. Sasaki, Y. M. Choi, Y. Chen, M. L. Liu, Energy Environ. Sci., 2022, 15, 287-295.
[42]	R. D. Shannon, Acta Crystallogr. A, Cryst. Phys. Diffr. Theor. Gen. Crystallogr. (Denmark), 1976, A32, 751-767.
[43]	X. Huang, J. Feng, H. R. S. Abdellatif, J. Zou, G. Zhang, C. Ni, Int. J. Hydrogen Energy, 2018, 43, 8962-8971.
[44]	T. Broux, M. Bahout, J. M. Hanlon, O. Hernandez, S. Paofai, A. Berenov, S. J. Skinner, J. Mater. Chem. A, 2014, 2, 17015-17023.
[45]	Y. Huang, F. He, K. Xu, H. Gao, X. Zhang, Y. Xu, Z. Du, F. Zhu, W. Gong, C. Jian, Y. Chen, Adv. Funct. Mater., 2024, 34, 2409598.
[46]	G. M. Rupp, A. K. Opitz, A. Nenning, A. Limbeck, J. Fleig, Nat. Mater., 2017, 16, 640-645.
[47]	X. Zhang, R. Song, D. Huan, K. Zhu, X. Li, H. Han, C. Xia, R. Peng, Y. Lu, Small, 2022, 18, 2205190.
[48]	K. Pei, S. Luo, F. He, J. Arbiol, Y. Xu, F. Zhu, Y. Wang, Y. Chen, Appl. Catal. B, 2023, 330, 122601.
[49]	Y. Zhou, W. Zhang, N. Kane, Z. Luo, K. Pei, K. Sasaki, Y. Choi, Y. Chen, D. Ding, M. Liu, Adv. Funct. Mater., 2021, 31, 2105386.
[50]	K. Xu, H. Zhang, Y. Xu, F. He, Y. Zhou, Y. Pan, J. Ma, B. Zhao, W. Yuan, Y. Chen, M. Liu, Adv. Funct. Mater., 2022, 32, 2110998.
[51]	H. Zhang, K. Xu, F. He, Y. Zhou, K. Sasaki, B. Zhao, Y. Choi, M. Liu, Y. Chen, Adv. Energy Mater., 2022, 12, 2200761.
[52]	F. Zhu, F. He, D. Liu, H. Zhang, Y. Xu, K. Xu, Y. Chen, Energy Storage Mater., 2022, 53, 754-762.
[53]	H. Gao, X. Chen, W. Gong, H. Liu, W. Lin, C. Jian, L. Zhang, T. Sheng, Y. Chen, J. Mater. Chem. A, 2025, 13, 16525-16532.
[54]	T.-H. Wan, M. Saccoccio, C. Chen, F. Ciucci, Electrochim. Acta, 2015, 184, 483-499.
[55]	T. Hu, F. Zhu, J. Xia, F. He, Z. Du, Y. Zhou, Y. Liu, H. Wang, Y. Chen, Adv. Funct. Mater., 2023, 33, 2305567.
[56]	F. He, F. Zhu, D. Liu, Y. Zhou, K. Sasaki, Y. Choi, M. Liu, Y. Chen, Mater. Today, 2023, 63, 89-98.
[57]	J. Xia, F. Zhu, F. He, K. Xu, Y. Choi, Y. Chen, Adv. Energy Mater., 2023, 13, 2302964.
[58]	F. He, H. Liu, Y. Xu, F. Zhu, K. Sasaki, Y. Choi, Y. Liu, Y. Chen, Joule, 2025, 9, 101957.
[59]	J. H. Kim, S. Yoo, R. Murphy, Y. Chen, Y. Ding, K. Pei, B. Zhao, G. Kim, Y. Choi, M. Liu, Energy Environ. Sci., 2021, 14, 1506-1516.
[60]	R. Ren, Z. Wang, C. Xu, W. Sun, J. Qiao, D. W. Rooney, K. Sun, J. Mater. Chem. A, 2019, 7, 18365-18372.
[61]	K. Xu, H. Zhang, Y. Xu, D. Liu, F. Zhu, F. He, Y. Liu, H. Wang, Y. Chen, Adv. Powder Mater., 2024, 3, 100187.
[62]	B. Koo, H. Kwon, Y. Kim, H. G. Seo, J. W. Han, W. Jung, Energy Environ. Sci., 2018, 11, 71-77.
[63]	M. Liang, F. He, C. Zhou, Y. Chen, R. Ran, G. Yang, W. Zhou, Z. Shao, Chem. Eng. J., 2021, 420, 127717.
[64]	T. Xia, N. Lin, H. Zhao, L. Huo, J. Wang, J.-C. Grenier, J. Power Sources, 2009, 192, 291-296.
[65]	X. Ding, Z. Gao, D. Ding, X. Zhao, H. Hou, S. Zhang, G. Yuan, Appl. Catal. B, 2019, 243, 546-555.
[66]	J. W. Stevenson, T. R. Armstrong, R. D. Carneim, L. R. Pederson, W. J. Weber, J. Electrochem. Soc., 1996, 143, 2722-2729.
[67]	J.-W. Moon, Y. Masuda, W.-S. Seo, K. Koumoto, Mater. Sci. Eng. B, 2001, 85, 70-75.
[68]	W. Guo, R. Guo, L. Liu, G. Cai, C. Zhang, C. Wu, Z. Liu, H. Jiang, Int. J. Hydrogen Energy, 2015, 40, 12457-12465.
[69]	E. Boehm, J. M. Bassat, M. C. Steil, P. Dordor, F. Mauvy, J. C. Grenier, Solid State Sci., 2003, 5, 973-981.
[70]	S. Shao, Z. Ding, C. Shang, S. Zhang, Y. Ke, G. Zhu, Y. Yang, Chem. Eng. J., 2022, 450, 138153.
[71]	M. Liang, Y. Zhu, Y. Song, D. Guan, Z. Luo, G. Yang, S.-P. Jiang, W. Zhou, R. Ran, Z. Shao, Adv. Mater., 2022, 34, 2106379.
[72]	J. Zhu, H. Li, L. Zhong, P. Xiao, X. Xu, X. Yang, Z. Zhao, J. Li, ACS Catal., 2014, 4, 2917-2940.
[73]	Y. Song, Y. Chen, W. Wang, C. Zhou, Y. Zhong, G. Yang, W. Zhou, M. Liu, Z. Shao, Joule, 2019, 3, 2842-2853.
[74]	M. Yang, Z. Yao, S. Liu, J. Wang, A. Sun, H. Xu, G. Yang, R. Ran, W. Zhou, G. Xiao, Z. Shao, J. Mater. Sci. Technol., 2023, 164, 160-167.
[75]	Y. S. Xu, H. Zhang, K. Xu, X. R. Zhang, F. Zhu, W. Q. Deng, F. He, Y. Liu, Y. Chen, Adv. Mater., 2024, 36, 2408044.
[76]	X. Wu, J. Wang, H. Tian, W. Li, C.-X. Li, Chem. Eng. J., 2025, 512, 162395.
[77]	Q. Lan, Y. Hua, Y. Li, Y. Gu, L. Bi, Ceram. Int., 2024, 50, 7202-7209.
[78]	Y. Yin, B. Liu, D. Yan, J. Li, L. Jia, SusMat, 2024, 4, e240.
[79]	Q. Wang, J. Hou, Y. Fan, X.-A. Xi, J. Li, Y. Lu, G. Huo, L. Shao, X.-Z. Fu, J.-L. Luo, J. Mater. Chem. A, 2020, 8, 7704-7712.
[80]	J. Kim, A. Jun, O. Gwon, S. Yoo, M. Liu, J. Shin, T.-H. Lim, G. Kim, Nano Energy, 2018, 44, 121-126.
[81]	W. Tang, W. Bian, H. Ding, Y. Ding, Z. Zhao, Q. Sun, S. Koomson, Y. Wang, B. Xu, P. Dong, D. Chen, J. Y. Gomez, W. Feng, W. Wu, M. Zhou, Y. Dong, H. Luo, J. Li, D. Ding, Nat. Synth, 2025, 4, 592-602.
[82]	K. Xu, Y. Xu, F. Zhu, Z. Du, X. Zhang, Z. Cheng, Y. Chen, Energy Environ. Sci., 2025, 18, 6722-6731.
[83]	H. Gao, F. He, F. Zhu, J. Xia, Z. Du, Y. Huang, L. Zhu, Y. Chen, Adv. Funct. Mater., 2024, 34, 2401747.
[84]	J. J. Xia, M. Y. Zhou, H. Gao, F. He, Z. W. Du, Y. Chen, Adv. Funct. Mater., 2024, 34, 2403493.