Borohydrides as Solid-State Hydrogen Storage Materials: Past, Current Approaches and Future Perspectives

For long, the focus on hydrogen as an energy vector has been towards vehicle applications to decrease air pollution across cities and reduce our reliance on fossil fuels for transport. However, hydrogen has also the p otential to enable the transition of current energy schemes towards clean and sustainable energy systems based on renewable energy. The major drawback remains the development of materials/methods for the safe storage of hydrogen with high-energy density. Recently, the idea of using borohydrides for hydrogen storage has gained increasing attention because of the high hydrogen density provided by these materials. However, the high temperatures for hydrogen release from these materials and their slow hydrogen kinetics remain the main challenges. Herein, current approaches to tailor the hydrogen storage properties of borohydrides towards practical applications are reviewed, including the restriction of borohydrides within various nanosized scaffolds. A summary of the remaining challenges and potential future research directions is also provided.