高温碱性电解制氢与碱性燃料电池发电研究进展

Progress of elevated-temperature alkaline electrolysis hydrogen production and alkaline fuel cells power generation

  • 摘要: 分别介绍了高温碱性电解制氢与碱性燃料电池发电的研究进展。高温碱性电解制氢多采用铂族金属与雷尼镍、不锈钢等Ni基合金作为电催化剂,而其电解质主要可分为KOH水溶液与KOH-NaOH-LiOH多元熔融体系,并结合采用流延烧结与电极支撑粉末烧结等方法制备的金属氧化物隔膜以实现氢氧产物分离,相关电解装置已在100−400 ℃实现超400 h稳定运行且衰减速率<0.1 V/kh;系统层面,实现130 ℃下20 kW稳定制氢,并提出允许多热源热-氢能源转换及高品位电-氢-热联产的吸/放热灵活转换运行模式。高温碱性燃料电池发电方面在电催化剂方面采用类似铂族金属与Ni及其氧化物,而其电解质除高浓度KOH水溶液与熔融氢氧化物外可采用高价金属掺杂焦磷酸盐等具备高电导率的固态材料。相关液态电解质装备已实现kW级地面与太空应用,且新型固态电解质单元已通过超160 h运行测试,而高温碱性膜燃料电池近年来取得长足发展,已实现超195 h稳定运行。

     

    Abstract: Progress of elevated-temperature alkaline electrolysis for hydrogen production and alkaline fuel cells for power generation are presented. Using platinum group metals and Ni-based alloys, such as Raney Ni and stainless steel, as electrocatalysts, alkaline water electrolysis adopts aqueous KOH solutions or molten KOH-NaOH-LiOH as liquid electrolytes, and combining with metal oxide diaphragms fabricated by tape casting sintering or electrode-supported powder sintering for product separation. Electrolysis longer than 400 hours at 100−400 ℃ and degradation rate of <0.1 V/kh have been realized. In system level, 20 kW stable water electrolysis at 130 ℃ has been realized, and flexible transition of endo/exothermic mode allowing multi-thermal-source thermo-hydrogen energy conversion and high value electric-hydrogen-heat coordination has been proposed. Relying on similar platinum group metals, Ni as well as its oxides as electrocatalysts, elevated-temperature alkaline fuel cells widen applicable electrolytes from aqueous KOH solutions and molten hydroxides to solid materials with adequate ionic conductivity, including high-valence metal doped phosphates. Equipment with liquid electrolyte have accomplished kW-level ground and space applications, while recently developed solid electrolyte cells have realized over 160 hours of continuous operation, while elevated-temperature alkaline membrane fuel cells have made significant progress in recent years, achieving stable operation for over 195 hours.

     

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