HyStor: An Experimental Database of Hydrogen Storage Properties for Various Metal Alloy Classes

In this work, we introduce the HyStor database, consisting of 1280 metal alloys along with their hydrogen storage capacities (H2wt%) as a function of absorption temperature. Given the lack of updates in the existing open access HydPark database since 2002, we sourced compositions from recent research articles and various patent documents, resulting in a total of 468 compositions. The addition is reflected in the data across all existing classes of alloy compositions and low entropy alloys (LEA), medium entropy alloys (MEA), and high entropy alloys (HEA) have been included newly. This has broadened the scope of the database to encompass the latest materials of interest for hydrogen storage. HyStor contains representation of 54 elements, with a temperature range of 200-800K, and H2wt% range of 0.1-7.19. To ensure data quality, we conducted thorough checks for duplicate entries, erroneous data, and conflicting compositions within the database. Furthermore, we conducted multiple tests to identify potential outlier compositions by benchmarking the database against the pretrained HYST model on HydPark data. After eliminating these potential outliers, we successfully improved the error metrics of the HYST model, reducing the Mean Absolute Error (MAE) from 0.32 to 0.28 and increasing the R2 score from 0.78 to 0.82. We also tested individual classes and observed that the performance of the HYST model has increased for majority of the classes.