Review on the characteristics of existing hydrogen energy storage technologies

ABSTRACTIn this paper, the characteristics of current hydrogen storage technologies are reviewed from the aspects of hydrogen storage capacity, working conditions, reversibility, and safety. Among the technologies mentioned herein, N-containing liquid organic hydrogen carriers (N-containing LOHCs) are regarded as an ideal hydrogen storage medium because of their excellent hydrogen storage performance. However, N-containing LOHCs are mostly hydrogenated/dehydrogenated by traditional thermal catalysis, which requires strict reaction conditions (120 ~ 200°C; 6 ~ 7 MPa) and external hydrogen supply. Thermal catalysis has high energy consumption and certain safety risks. The electrochemical method can hydrogenate/dehydrogenate organic substrates under mild conditions (25 ~ 60°C; normal pressure) and does not require an external H2 supply. Therefore, electrochemical hydrogen storage technology based on N-containing LOHCs has great development potential.KEYWORDS: Hydrogen storage technologiesliquid organic hydrogen carriersN-heterocyclic organic compoundselectrochemical hydrogen storage Nomenclature N-containing=Nitrogen-containingLOHCs=Liquid organic hydrogen carriersDOE=Department of EnergyIEA=International Energy AgencyMOFs=Metal-organic framework materialsBCNTs=Boron-doped carbon nanotubesCMC=Carboxymethyl celluloseMWCNTs=Multiwalled carbon nanotubes[BH4]=Borohydride[AlH4]=Aluminum hydride[NH2/NH3]=Amino compoundCD=CyclodextrinTMC=Trimethyl chlorideNEC=N-ethylcarbazoleTOF=Turnover frequencyRgo=Reduced graphene oxideH-spillover=Hydrogen-spilloverAC=Activated carbonAPCF=Activated porous carbon fiberHEG=Hydrogen exfoliated grapheneNPC=Nitrogen-doped porous carbon$=U.S. dollarSubscripts ads=AdsorbentKWH=Kilowatt hour.Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThe work was supported by the Key R&D Projects of Jilin Provincial Department of Science and Technology [Grant No. 20210201058GX]; Fundamental Research Funds for the Central Universities [Grant No. 2019MS102].