Thermodynamics of the cyclic formate/bicarbonate interconversion for hydrogen storage

Aqueous formate/bicarbonate solutions are gaining special attention as a promising system for intrinsically safe hydrogen storage. In the last years, a growing number of papers are investigating catalytic systems to enhance salts interconversion at near-ambient conditions. In this work, we present detailed thermodynamic calculations to clarify the maximum storage capacity of such a system. The model is validated against experimental results reported in the literature and the influence of operating conditions is addressed. Based on the results, the performances of the most promising configurations are simulated for experimental benchmarking and future technological development. Thermodynamic limitations show that maximum volumetric density is lower than traditional physical-based H2 storage, but with considerable advantage from a safety point of view.