Expanding the Material Search Space for Multivalent Cathodes.

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Multivalent batteries offer superior energy storage potential compared to lithium-ion batteries.
• Current multivalent cathode performance is hindered by low voltages and poor ionic mobility.
• Expanding the search space for cathode materials is crucial for advancing this technology.

Purpose of the Study:

• To develop a computational screening approach for identifying high-performance multivalent intercalation cathodes.
• To explore candidate materials beyond those containing the specific working ion.
• To investigate magnesium (Mg2+) cathodes as a proof of concept.

Main Methods:

• Employed a computational screening strategy to identify novel multivalent cathode materials.
• Applied the approach to magnesium cathodes, screening a wide range of materials.
• Analyzed ion migration pathways and energy barriers for Mg2+ in candidate materials.

Main Results:

• Identified four promising multivalent cathode candidates: NASICON V2(PO4)3, birnessite NaMn4O8, tavorite MnPO4F, and spinel MnO2.
• Found that Mg2+ migration energy is influenced by local bonding environments and available free volume.
• Observed that local energy maxima correlate with Mg2+ passing through anion planes.

Conclusions:

• The developed computational method significantly broadens the scope for discovering multivalent battery materials.
• Understanding the interplay between local bonding and free volume is key to enhancing solid-state ionic mobility.
• The identified candidate materials show promise for future high-performance multivalent battery applications.