Embodiments of an electrolyte for a hybrid magnesium-alkali metal ion battery are disclosed. The electrolyte includes a magnesium salt, a Lewis acid, and an alkali metal salt. Embodiments of battery systems including the electrolyte also are disclosed.
ACKNOWLEDGMENT OF GOVERNMENT SUPPORT
 This invention was made with government support under DE-AC0576RLO1830 awarded by the U.S. Department of Energy. The government has certain rights in the invention.