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Item type:Publication, Access status: without files , Liquid organic hydrogen carriers (LOHCs)-techno-economic analysis of LOHCs in a defined process chain(2019-01); ; ; © 2019 The Royal Society of Chemistry. Long-distance transport and long-term storage of hydrogen can be realized with Liquid Organic Hydrogen Carriers (LOHC) based on a two-step cycle: (1) loading of hydrogen (hydrogenation) into the LOHC molecule (i.e., hydrogen is covalently bound to the LOHC) and (2) unloading of hydrogen (dehydrogenation) after transport and storage. Since the (optimal) LOHC is liquid at ambient conditions and shows similar properties to crude oil based liquids (e.g. diesel, and gasoline), handling and storage is realized by well-known processes; thus stepwise adaptation of the existing crude oil based infrastructure is basically possible. Against this background, a defined process chain for intercontinental ship transport of hydrogen (5000 km) is simulated with various LOHCs. The respective results are evaluated and assessed related to their technological and economic performance. Additionally, they are compared to a pipeline-based provision chain based on compressed hydrogen (CGH2). Among others, the results show that methanol is the cheapest LOHC option for storage and transportation followed by dibenzyltoluene and toluene. For a storage time of 60 days they show economic advantages compared to compressed hydrogen (CGH2) under the defined assumptions; thus these LOHC options are especially advantageous for long-term storage/long distance transport applications. The energetic efficiency of the systems mainly depends on the source of the dehydrogenation heat. Two options, dehydrogenation driven by hydrogen burning vs. dehydrogenation driven by waste heat, have been evaluated in this study. Systems that run on waste heat perform much better in terms of efficiency. Overall, LOHCs can provide technologically efficient and economic promising storage and transport within a sustainable hydrogen economy.Publicationtype: Journal Article518 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Concentrated mixed cation acetate "water-in-salt" solutions as green and low-cost high voltage electrolytes for aqueous batteriesElectrolyte solutions are a key component of energy storage devices that significantly impact capacity, safety, and cost. Recent developments in "water-in-salt" (WIS) aqueous electrolyte research have enabled the demonstration of aqueous Li-ion batteries that operate with capacities and cyclabilities comparable with those of commercial non-aqueous Li-ion batteries. Critically, the use of aqueous electrolyte mitigates safety risks associated with non-aqueous electrolytes. However, the high cost and potential toxicity of imide-based WIS electrolytes limit their practical deployment. In this report, we disclose the efficacy of inexpensive, non-toxic mixed cation electrolyte systems for Li-ion batteries that otherwise provide the same benefits as current WIS electrolytes: extended electrochemical stability window and compatibility with traditional intercalation Li-ion battery electrode materials. We take advantage of the high solubility of potassium acetate to achieve the WIS condition in a eutectic mixture of lithium and potassium acetate with water-to-cation ratio as low as 1.3. Our work suggests an important direction for the practical realization of safe, low-cost, and high-performance aqueous Li-ion batteries.Publicationtype: Journal Article28