of the additives on charge/discharge performance
were discussed. It was found that the oxidation potential of alkaline ions and the radii of halogen ions
are linearly correlated with electrode degradation. For oxyacid salt electrolytes, a synergistic effect
between the salt and KOH was observed: (1) a solid film forms on the MgNi particle surface, which
physically prevents corrosion from KOH electrolyte and boosts discharge capacity; (2) H-transfer is
promoted in aqueous electrolyte, which decreases degradation.
A brief discuss for H-transfer in the additive containing electrolyte system was included based on
the screen test data. H bond type in the novel electrolyte system is not similar to traditional KOH
electrolyte. Both type 1 and 2 hydrogen bonds exist in the additives containing electrolytes. Because of
the formation of the solid film on the MgNi particles, the H-delivery mechanism in the novel electrolyte
is also different from traditional KOH electrolytes. Both vehicle mechanism and structure-diffusion
mechanism occurred in the novel electrolyte system. As the synergistic effect is determined by the nature
of the salt additive, the factors that could influence the electro-performance were discussed based on
the salt additive’s chemical properties including the salt’s anion’s basicity, amount of base sites,
stability during charging/discharging, solubility in KOH solution, and ionic charge.