Six-armed twin crystals composed of lithium iron silicate nanoplates and their electrochemical properties

Abstract

Orthorhombic lithium iron silicate (Li₂FeSiO₄) twin crystals with a novel six-fold symmetrical shape were prepared by a hydrothermal process. The specific six-armed structure was composed of single-crystalline unit plates surrounded by large (100) faces with a thickness of ca. 100 nm. Because of the short diffusion length of Li⁺ ions along [100], the six-armed twin crystals were advantageous for a cathode material of Li-ion batteries. We found the improved rate and cycle performance of the six-armed twin crystals without any carbon coatings by comparing them with random aggregates of Li₂FeSiO₄ nanoparticles. The design of particle morphology on the basis of the Li⁺ ion diffusion is effective for enhancing the electrochemical performance of active materials.