[2] [2] LIU F, DING D, DUAN C C. Protonic ceramic electrochemical cells for synthesizing sustainable chemicals and fuels[J]. Adv Sci, 2023, 10(8): e2206478.

[3] [3] DUAN C C, HUANG J, SULLIVAN N, et al. Proton-conducting oxides for energy conversion and storage[J]. Appl Phys Rev, 2020, 7(1): 011314.

[4] [4] FABBRI E, MAGRASó A, PERGOLESI D. Low-temperature solid-oxide fuel cells based on proton-conducting electrolytes[J]. MRS Bull, 2014, 39(9): 792-797.

[5] [5] HE F, SONG D, PENG R R, et al. Electrode performance and analysis of reversible solid oxide fuel cells with proton conducting electrolyte of BaCe0.5Zr0.3Y0.2O3-δ[J]. J Power Sources, 2010, 195(11): 3359-3364.

[6] [6] LIM D K, IM H N, SINGH B, et al. Investigations on electrochemical performance of a proton-conducting ceramic-electrolyte fuel cell with La0.8Sr0.2MnO3 Cathode[J]. J Electrochem Soc, 2015, 162(6): F547-F554.

[7] [7] SUN S C, CHENG Z. Electrochemical behaviors for Ag, LSCF and BSCF as oxygen electrodes for proton conducting IT-SOFC[J]. J Electrochem Soc, 2017, 164(10): F3104-F3113.

[8] [8] HOU J, MIAO L N, HUI J N, et al. A novel in situ diffusion strategy to fabricate high performance cathodes for low temperature proton-conducting solid oxide fuel cells[J]. J Mater Chem A, 2018, 6(22): 10411-10420.

[9] [9] DUAN C C, TONG J H, SHANG M, et al. Readily processed protonic ceramic fuel cells with high performance at low temperatures[J]. Science, 2015, 349(6254): 1321-1326.

[10] [10] XU X M, ZHONG Y J, SHAO Z P. Double perovskites in catalysis, electrocatalysis, and photo(electro)catalysis[J]. Trends Chem, 2019, 1(4): 410-424.

[11] [11] WACHOWSKI S L, SZPUNAR I, S?RBY M H, et al. Structure and water uptake in BaLnCo2O6-δ (Ln=La, Pr, Nd, Sm, Gd, Tb and Dy)[J]. Acta Mater, 2020, 199: 297-310.

[12] [12] LIU B, JIA L C, CHI B, et al. A novel PrBaCo2O5+σ- BaZr0.1Ce0.7Y0.1Yb0.1O3 composite cathode for proton-conducting solid oxide fuel cells[J]. Compos Part B Eng, 2020, 191: 107936.

[13] [13] KIM J, SENGODAN S, KWON G, et al. Triple-conducting layered perovskites as cathode materials for proton-conducting solid oxide fuel cells[J]. ChemSusChem, 2014, 7(10): 2811-2815.

[14] [14] ZHANG H, ZHOU Y C, PEI K, et al. An efficient and durable anode for ammonia protonic ceramic fuel cells[J]. Energy Environ Sci, 2022, 15(1): 287-295.

[15] [15] DING P P, LI W L, ZHAO H W, et al. Review on Ruddlesden-Popper perovskites as cathode for solid oxide fuel cells[J]. J Phys Mater, 2021, 4(2): 022002.

[16] [16] XU X M, SHAO Z P, JIANG S P. High-entropy materials for water electrolysis[J]. Energy Tech, 2022, 10(11): 2200573.

[17] [17] LING Y H, HAN X, YANG Y, et al. Stable High-Entropy Double Perovskite Cathode SmBa(Mn0.2Fe0.2Co0.2Ni0.2Cu0.2)2O5+δ for Intermediate-Temperature Solid Oxide Fuel Cells[J]. J Chin Ceram Soc, 2022, 50(1): 219-225.

[18] [18] PAPAC M, STEVANOVI? V, ZAKUTAYEV A, et al. Triple ionic-electronic conducting oxides for next-generation electrochemical devices[J]. Nat Mater, 2021, 20(3): 301-313.

[19] [19] JIN F J, LING Y H. Performance of calcium doping in layered double perovskite as cathode material for solid oxide fuel cells[J]. J Chin Ceram Soc, 2023, 51(7): 1773-1782.

[20] [20] ZHU K, YANG Y, HUAN D M, et al. Theoretical and experimental investigations on K-doped SrCo0.9Nb0.1O3-δ as a promising cathode for proton-conducting solid oxide fuel cells[J]. ChemSusChem, 2021, 14(18): 3876-3886.

[21] [21] WANG Z, LV P F, YANG L, et al. Ba0.95La0.05Fe0.8Zn0.2O3-δ cobalt-free perovskite as a triple-conducting cathode for proton-conducting solid oxide fuel cells[J]. Ceram Int, 2020, 46(11): 18216-18223.

[22] [22] JING J M, LEI Z, WU Z, et al. Ba0.95La0.05Fe0.8Ni0.2O3-δ perovskite as efficient cathode electrocatalysts for proton-conducting solid oxide fuel cells[J]. J Eur Ceram Soc, 2022, 42(14): 6566-6573.

[23] [23] WANG Z, WANG Y H, WANG J, et al. Rational design of perovskite ferrites as high-performance proton-conducting fuel cell cathodes[J]. Nat Catal, 2022, 5: 777-787.

[24] [24] ZOHOURIAN R, MERKLE R, RAIMONDI G, et al. Mixed- conducting perovskites as cathode materials for protonic ceramic fuel cells: Understanding the trends in proton uptake[J]. Adv Funct Mater, 2018, 28(35): 1801241.

[25] [25] ZHANG Z B, ZHU Y L, ZHONG Y J, et al. Anion doping: A new strategy for developing high-performance perovskite-type cathode materials of solid oxide fuel cells[J]. Adv Energy Mater, 2017, 7(17): 1700242.

[26] [26] WANG H R, LEI Z, JING J M, et al. Evaluation of NdBaCo2O5+δ oxygen electrode combined with negative expansion material for reversible solid oxide cells[J]. J Eur Ceram Soc, 2022, 42(10): 4259-4265.

[27] [27] YI Y N, RAN R, WANG W, et al. Perovskite-based nanocomposites as high-performance air electrodes for protonic ceramic cells[J]. Curr Opin Green Sustain Chem, 2022, 38: 100711.

[28] [28] NIU Y H, ZHOU Y C, ZHANG W L, et al. Highly active and durable air electrodes for reversible protonic ceramic electrochemical cells enabled by an efficient bifunctional catalyst[J]. Adv Energy Mater, 2022, 12(12): 2103783.

[29] [29] SONG Y F, CHEN Y B, WANG W, et al. Self-assembled triple-conducting nanocomposite as a superior protonic ceramic fuel cell cathode[J]. Joule, 2019, 3(11): 2842-2853.

[30] [30] ZHAO Z Y, CUI J, ZOU M D, et al. Novel twin-perovskite nanocomposite of Ba-Ce-Fe-Co-O as a promising triple conducting cathode material for protonic ceramic fuel cells[J]. J Power Sources, 450: 866-875.

[31] [31] ZHOU C, WANG X X, LIU D L, et al. New strategy for boosting cathodic performance of protonic ceramic fuel cells through incorporating a superior hydronation second phase[J]. Energy Environ Materials, 2023: 12660.

[32] [32] KIM J H, HONG J, LIM D K, et al. Water as a hole-predatory instrument to create metal nanoparticles on triple-conducting oxides[J]. Energy Environ Sci, 2022, 15(3): 1097-1105.

[33] [33] XU K, ZHANG H, XU Y S, et al. An efficient steam-induced heterostructured air electrode for protonic ceramic electrochemical cells[J]. Adv Funct Mater, 2022, 32(23): 2110998.

[34] [34] ZHOU Y C, LIU E Z, CHEN Y, et al. An active and robust air electrode for reversible protonic ceramic electrochemical cells[J]. ACS Energy Lett, 2021: 1511-1520.

[35] [35] SCHEFOLD J, BRISSE A, POEPKE H. 23 000 h steam electrolysis with an electrolyte supported solid oxide cell[J]. Int J Hydrog Energy, 2017, 42(19): 13415-13426.

[36] [36] CHOI S, KUCHARCZYK C J, LIANG Y G, et al. Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells[J]. Nat Energy, 2018, 3: 202-210.

[37] [37] LE L Q, HERNANDEZ C H, RODRIGUEZ M H, et al. Proton- conducting ceramic fuel cells: Scale up and stack integration[J]. J Power Sources, 2021, 482: 228868.

[38] [38] LE L Q, MEISEL C, HERNANDEZ C H, et al. Performance degradation in proton-conducting ceramic fuel cell and electrolyzer stacks[J]. J Power Sources, 2022, 537: 231356.

[39] [39] YANG S J, CHANG W, JEONG H J, et al. High-performance protonic ceramic fuel cells with electrode-electrolyte composite cathode functional layers[J]. Int J Energy Res, 2022, 46(5): 6553-6561.

[40] [40] BIAN W J, WU W, WANG B M, et al. Revitalizing interface in protonic ceramic cells by acid etch[J]. Nature, 2022, 604(7906): 479-485.

[41] [41] ZHANG Y, CHEN B, GUAN D Q, et al. Thermal-expansion offset for high-performance fuel cell cathodes[J]. Nature, 2021, 591(7849): 246-251.

[42] [42] CHOI M, KIM S J, LEE W. Effects of water atmosphere on chemical degradation of PrBa0.5Sr0.5Co1.5Fe0.5O5+δ electrodes[J]. Ceram Int, 2020, 47(6): 7790-7797.

[43] [43] PAN J X, YE Y J, ZHOU M Z, et al. Revealing the impact of steam concentration on the activity and stability of double-perovskite air electrodes for proton-conducting electrolysis cells[J]. Energy Fuels, 2022, 36(19): 12253-12260.

[44] [44] BAUSá N, SOLíS C, STRANDBAKKE R, et al. Development of composite steam electrodes for electrolyzers based on Barium zirconate[J]. Solid State Ion, 2017, 306: 62-68.

[45] [45] DUAN C C, KEE R, ZHU H Y, et al. Highly efficient reversible protonic ceramic electrochemical cells for power generation and fuel production[J]. Nat Energy, 2019, 4: 230-240.

[46] [46] SHARMA V, MAHAPATRA M K, KRISHNAN S, et al. Effects of moisture on (La, A)MnO3 (A=Ca, Sr, and Ba) solid oxide fuel cell cathodes: A first-principles and experimental study[J]. J Mater Chem A, 2016, 4(15): 5605-5615.

[47] [47] V?LLESTAD E, STRANDBAKKE R, TARACH M, et al. Mixed proton and electron conducting double perovskite anodes for stable and efficient tubular proton ceramic electrolysers[J]. Nat Mater, 2019, 18(7): 752-759.

[48] [48] SHIN J S, PARK H, PARK K, et al. Activity of layered swedenborgite structured Y0.8Er0.2BaCo3.2Ga0.8O7+δ for oxygen electrode reactions in at intermediate temperature reversible ceramic cells[J]. J Mater Chem A, 2021, 9(1): 607-621.

[49] [49] HE F, ZHOU Y C, HU T, et al. An efficient high-entropy perovskite-type air electrode for reversible oxygen reduction and water splitting in protonic ceramic cells[J]. Adv Mater, 2023, 35(16): e2209469.

[50] [50] YANG S J, WEN Y B, ZHANG J C, et al. Electrochemical performance and stability of cobalt-free Ln1.2Sr0.8NiO4 (Ln=La and Pr) air electrodes for proton-conducting reversible solid oxide cells[J]. Electrochim Acta, 2018, 267: 269-277.

[51] [51] DANILOV N, LYAGAEVA J, VDOVIN G, et al. Electricity/hydrogen conversion by the means of a protonic ceramic electrolysis cell with Nd2NiO4+δ-based oxygen electrode[J]. Energy Convers Manag, 2018, 172: 129-137.

[52] [52] LI W Y, GUAN B, MA L, et al. High performing triple-conductive Pr2NiO4+δ anode for proton-conducting steam solid oxide electrolysis cell[J]. J Mater Chem A, 2018, 6(37): 18057-18066.

[53] [53] TANG W, DING H P, BIAN W J, et al. An unbalanced battle in excellence: Revealing effect of Ni/co occupancy on water splitting and oxygen reduction reactions in triple-conducting oxides for protonic ceramic electrochemical cells[J]. Small, 2022, 18(30): e2201953.

[54] [54] ZHOU Y C, ZHANG W L, KANE N, et al. An efficient bifunctional air electrode for reversible protonic ceramic electrochemical cells[J]. Adv Funct Mater, 2021, 31(40): 2105386.

[55] [55] LIANG M Z, WANG Y H, SONG Y F, et al. High-temperature water oxidation activity of a perovskite-based nanocomposite towards application as air electrode in reversible protonic ceramic cells[J]. Appl Catal B Environ, 2023, 331: 122682.

[56] [56] ZHAO Z, LIU L, ZHANG X M, et al. High- and low- temperature behaviors of La0.6Sr0.4Co0.2Fe0.8O3-δ cathode operating under CO2/H2O- containing atmosphere[J]. Int J Hydrog Energy, 2013, 38(35): 15361-15370.

[57] [57] DUAN C C, HOOK D, CHEN Y C, et al. Zr and Y Co-doped perovskite as a stable, high performance cathode for solid oxide fuel cells operating below 500 ℃[J]. Energy Environ Sci, 2017, 10(1): 176-182.

[58] [58] WEI Z L, LI Z B, WANG Z H, et al. A free-cobalt Barium ferrite cathode with improved resistance against CO2 and water vapor for protonic ceramic fuel cells[J]. Int J Hydrog Energy, 2022, 47(27): 13490-13501.

[59] [59] LV X Q, CHEN H L, ZHOU W, et al. SrCo0.4Fe0.4Zr0.1Y0.1O3-δ, A new CO2 tolerant cathode for proton-conducting solid oxide fuel cells[J]. Renew Energy, 2022, 185: 8-16.

[60] [60] SOZAL M S I, TANG W, DAS S, et al. Electrical, thermal, and H2O and CO2 poisoning behaviors of PrNi0.5Co0.5O3-δ electrode for intermediate temperature protonic ceramic electrochemical cells[J]. Int J Hydrog Energy, 2022, 47(51): 21817-21827.

[61] [61] XU Y S, XU X, BI L. A high-entropy spinel ceramic oxide as the cathode for proton-conducting solid oxide fuel cells[J]. J Adv Ceram, 2022, 11(5): 794-804.

[62] [62] HILPERT K, DAS D, MILLER M, et al. Chromium vapor species over solid oxide fuel cell interconnect materials and their potential for degradation processes[J]. J Electrochem Soc, 1996, 143(11): 3642-3647.

[63] [63] CHEN K F, AI N, O’DONNELL K M, et al. Highly chromium contaminant tolerant BaO infiltrated La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes for solid oxide fuel cells[J]. Phys Chem Chem Phys, 2015, 17(7): 4870-4874.

[64] [64] ZHEN Y D, TOK A I Y, JIANG S P, et al. La(Ni, Fe)O3 as a cathode material with high tolerance to chromium poisoning for solid oxide fuel cells[J]. J Power Sources, 2007, 170(1): 61-66.

[65] [65] HORITA T. Chromium poisoning for prolonged lifetime of electrodes in solid oxide fuel cells-Review[J]. Ceram Int, 2021, 47(6): 7293-7306.

[66] [66] FU M Y, JIN Y M, LI D, et al. Effect of Gd0.2Ce0.8O1.9 Immersion on Chromium Poisoning Behavior of La0.8Sr0.2Co0.2Fe0.8O3-δ Cathode of Solid Oxide Fuel Cells[J]. J Ceram, 2022, 43(1): 54-61.

[67] [67] LI J, LI J, YAN D, et al. Promoted Cr-poisoning tolerance of La2NiO4+δ-coated PrBa0.5Sr0.5Co1.5Fe0.5O5+δ cathode for intermediate temperature solid oxide fuel cells[J]. Electrochim Acta, 2018, 270: 294-301.

[68] [68] ZHANG H, XU K, HE F, et al. Surface regulating of a double-perovskite electrode for protonic ceramic fuel cells to enhance oxygen reduction activity and contaminants poisoning tolerance[J].Adv Energy Mater, 2022, 12(26): 2200761.