Challenges and opportunities for using formate to store, transport, and use hydrogen

In this perspective article, the synthesis and thermodynamic properties of aqueous solutions of formate salts (FS, HCO2-) are described in relationship to the concept of H-2 carriers. The physiochemical properties of solid FS, aqueous formate solutions, and aqueous bicarbonate solutions set the limitations for storage capacity, deliverable capacity, and usable H-2 capacity of these H-2 carriers, respectively. These parameters will help in the design of systems that use H-2 carriers for storage and transport of H-2 for fuel cell power applications. FS, as well as admixtures with formic acid (FA, H2CO2), have potential to address the goals outlined in the U.S. Department of Energy's H2@scale initiative to store in chemical bonds a significant quantity of energy (hundreds of megawatts) obtained from large scale renewable resources. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.