Growth behavior of LiMn₂O₄ particles formed by solid-state reactions in air and water vapor

Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn₂O₄ particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn₂O₄ particles in air and water vapor atmospheres as model reactions; LiMn₂O₄ is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO₃ precursor impregnated with LiOH, LiMn₂O₄ spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled. - Graphical abstract: This study has demonstrated a new strategy towards achieving morphology control without the use of additives during conventional solid-state reactions by exploiting water vapor-induced particle growth. - Highlights: • A new strategy to control the morphology of LiMn₂O₄ particles is proposed. • Water vapor-induced particle growth is exploited in solid-state reactions. • The microstructural evolution of LiMn₂O₄ particles is investigated. • The shape, size and microstructure can be controlled by solid-state reactions.