Proton ceramic fuel cell

China energy storage Network News: Proton Ceramic Fuel Cell (PCFC) can directly use hydrogen and hydrocarbon as fuel to generate electricity like high-temperature solid oxide fuel cell (SOFC), fuel efficiency can be more than 50%. However, most of the previous studies on direct hydrocarbon fuel cells have focused on solid oxide fuel cells based on oxygen ion-conducting electrolytes. Carbon deposition (coking) usually occurs when such fuel cells use hydrocarbon compounds and/or sulfur-containing fuels directly. And sulfur poisoning, resulting in severe degradation of battery performance over time. Although proton ceramic fuel cells exhibit good electrical properties and anti-coking properties, previous studies have not systematically compared them.

ChuanchengDuan from Colorado University of Mining and Technology (a work, Chinese name may be Duan Chuancheng, graduated from Dalian Polytechnic in 2012, graduated from Dalian Institute of Chemical Technology in 1 year) and RyanO'Hayre (communication) and others based on changes in battery structure The proton ceramic fuel cell was tested with 11 kinds of fuels, and the PCFC was systematically studied.

The authors directly used 11 unpretreated fuels, but the fuel cells showed excellent performance, especially the performance of NH3 and CH3OH fuels was almost close to that of pure hydrogen, even after 1000 hours of operation using H2S-contaminated natural gas. Battery performance has not dropped significantly. The PCFC can maintain a higher operating voltage than the SOFC, especially high fuel utilization. For all fuels, PCFC did not observe signs of coking during operation, and the temperature did not fluctuate greatly. In most cases, the performance degradation rate of the battery per 1000 hours was <1.5%. This is because the PCFC generates a uniform Ni nano-coating in the electrolyte phase after high-temperature operation. This coating can cooperate with BZY (doped yttrium zirconate BaZr0.8Y0.2O3–δ) to inhibit coke production, and they also A greater amount of sulfur poisoning can be tolerated by a self-cleaning sulfur removal mechanism.

A further explanation is that the electrolyte of PCFC is highly alkaline, while the common SOFC is more acidic, so the chemical difference of the surface can greatly affect the performance of the electrode. The hydration of BZY/BCY can increase the O:C ratio at the surface and the two-phase interface, which helps to increase the carbonization resistance. The presence of proton-conducting ceramic particles in the anode can also inhibit the adsorption of sulfur and contribute to sulfur removal. Density functional theory studies show that COOH(Ni) is most likely to form one of three carbon-containing hydroxyl species on the surface of Ni(111) and Ni(211). Previous studies have shown that the rate of WGS (water–gasshift) determines that the step reaction is the formation of COOH (Ni). The removal rate of coke is directly proportional to the rate of COOH (Ni) formation.

Thermal stability is critical to the commercialization of fuel cells. Rapid thermal cycling of PCFCs using hydrogen as fuel, after each thermal cycle and all 32 thermal cycles are completed, the current density of the battery can be restored to >99.5% of its initial current density, indicating that the PCFC battery material is highly stable The inherent thermal cycling capability. The excellent fuel suitability and long-term durability exhibited by Ni-BZY-based PCFC devices, as well as its inherent thermal cycling stability, highlight the broad prospects of this technology and the potential for commercial applications.

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