  The search for suitable materials for solid-state stationary storage of green
hydrogen is pushing the implementation of efficient renewable energy systems.
This involves rational design and modification of cheap alloys for effective
storage in mild conditions of temperature and pressure. Among many
intermetallic compounds described in the literature, TiFe-based systems have
recently regained vivid interest as materials for practical applications since
they are low-cost and they can be tuned to match required pressure and
operation conditions. This work aims to provide a comprehensive review of
publications involving chemical substitution in TiFe-based compounds for
guiding compound design and materials selection in current and future hydrogen
storage applications. Mono- and multi-substituted compounds modify TiFe
thermodynamics and are beneficial for many hydrogenation properties. They will
be reviewed and deeply discussed, with a focus on manganese substitution.
