Exploration of tetrahedral structures in silicate cathodes using a motif-network scheme

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Dilithium/disodium transition metal orthosilicates (A2MSiO4) are important inorganic compounds.
• Understanding their crystal structures is crucial for materials design.

Purpose of the Study:

• To investigate the tetrahedral structures of A2MSiO4 compounds (A=Li, Na; M=Mn, Fe, Co).
• To discover novel crystal structures and analyze trends in structural stability.
• To predict ground-state structures for less-studied sodium systems.

Main Methods:

• Utilized a motif-network search scheme to explore structural possibilities.
• Classified discovered structures based on their M-Si-O framework dimensionality (1D, 2D, 3D).
• Analyzed energy degeneracy and identified trends in structural preferences.

Main Results:

• Identified all previously reported structures and discovered numerous new, energetically degenerate structures.
• Classified structures into 1D, 2D, and 3D M-Si-O frameworks.
• Revealed clear trends in structural preferences and introduced indicators for stability.
• Predicted ground-state structures for sodium systems, suggesting new structural motifs.

Conclusions:

• The study expands the known structural landscape of A2MSiO4 compounds.
• Structural preferences exhibit clear trends influenced by specific elemental compositions.
• New structural motifs are predicted for sodium-based orthosilicates, warranting further experimental investigation.