The contrast between monovalent and multivalent metal battery anodes

Monovalent (lithium, sodium, potassium) and multivalent (magnesium, calcium, aluminum) metal anodes are promising alternatives to graphite anodes for overcoming the performance limitations of lithium-ion batteries. In this Review, we compare and contrast their electrochemical behaviors in nonaqueous electrolytes by discussing their common challenges of irregular metal deposition and unstable solid electrolyte interphases (SEIs), as well as their differences, which are due to dissimilar surface energies and cation charge densities. General design strategies for electrode, electrolyte, and interphase are proposed to enable horizontally deposited metals with preferred crystallographic orientations and stable SEIs with distinct chemical compositions yet similar structural homogeneity. Finally, we assess the specific advantages and unresolved challenges of each system, providing cross-disciplinary insights to advance high-energy and low-cost metal-anode batteries for next-generation energy storage.