报告题目：Electrodics for Protonics
Truls Norby，挪威奥斯陆大学化学系教授。国际固体离子学会（International Society of Solid State Ionics）现任主席（2019-2021），挪威科学与文学院（Norwegian Academy of Science and Letters）、挪威科学与技术学院（Norwegian Academy of Science and Technology）、阿格德科学与文学院（Agder Academy of Science and Letters）院士，Solid State Ionics（Elsevier）编辑、挪威化学学会无机与材料化学组首席科学家、Solid State Ionics及Solid State Protonic Conductors等国际会议的顾问团成员。
Norby教授是固体离子导体，特别是固体质子导体的顶尖学者。主要研究方向为固体材料中的缺陷化学，固体氧化物型质子导体在燃料电池、电解制氢池、电化学反应器、传感器等电化学器件中的应用，电极界面以及固体表面化学分析等，此外，当前对光电化学以及热电材料也正开展研究。已指导毕业博士生33人、硕士生57人；在Science、Nature、Nature Materials、Nature Energy等期刊上发表学术论文220余篇；创办NorECs和Protia AS公司，致力于质子导电材料的实用化研发。
Recent years have seen promising progress and demonstrations of proton ceramic fuel cells, electrolysers, and reactors with BaZrO3-based electrolytes. While robust and cheap fabrication of such electrolytes with low overall resistance still pose challenges, other components deserve equally much attention, notably sealing, interconnects, current collection, and not least electrodes.
The study and development of electrodes for solid electrolytes is generally troubled by the inherent complexity, yet poor establishment of the theory and interpretation of the many types of charge and mass transfers at the many interfaces involved. For proton ceramics, we have the additional problem that three carriers – protons, oxide ions, and electrons – often contribute significantly in the electrolyte. Failure to recognise this may lead to erroneously parameterised electrode kinetics, and lost possibilities to improve kinetics and faradayic and process efficiencies.
Electrodes on the reducing (hydrogen) side of fuel cells and electrolysers – hereafter denoted negatrodes – usually have Ni as electron conducting and electrocatalytic component, while Cu is considered for use in coking (e.g. CH4) atmospheres. Charge and mass transfer on such metals as well as Pt as model electrode appears to follow expected pathways and theories. There are experimental and computational indications that a charged metal-electrolyte interface and the associated space charge region in the electrolyte adds a significant resistance due to depletion of protons.
On the positrode side, however, the process must necessarily be more complicated, involving adsorption/desorption of both oxygen and water vapour molecules, a variety of possible mobile intermediate species and pathways on surfaces and in bulk of the oxide electrodes, and experimental challenges. The amount of reliable parameterisation is therefore limited. Minor mixed proton conduction in oxide electrode materials expands the active area for charge transfer, and is under investigation.
The role of oxide ion conductivity in the positrode materials – giving rise to the term triple conducting oxides (TCOs) – is questionable for proton conducting electrolytes, but may enhance and control co-ionic (proton and oxide ion) operation.
All in all, the prospects of proton ceramic electrochemical cells rely on developments based on systematic studies and critical interpretation and parametrisation properly founded on electrode theory.