Molten Salt Synthesis of Multifaceted Pure-Phase Spinel LiNi _0.5 Mn _1.5 O ₄ Platelets

The spinel LiNi 0.5 Mn 1.5 O 4 is largely studied as a positive electrode material for lithium-ion batteries, but further optimization of its properties is required to enable its commercialization. The superior electrochemical performance of the disordered polymorph of LiNi 0.5 Mn 1.5 O 4 is limited by its traditional method of synthesis. This solid-state route generates impurities that reduce the specific capacity and results in the formation of octahedral particles with exposed {111} facets, thus limiting exploration of the effects of surface orientation. In this work, we report for the first time the preparation of a disordered impurity-free LiNi 0.5 Mn 1.5 O 4 with platelet-like morphology via molten salt synthesis. We discovered that these platelets exhibit multiple surface orientations, including {111}, {112}, and six other high-indexed facets, and deliver energy storage performance equivalent to that of their octahedral counterpart. Such an ability to tune primary particle morphology and orientation will open the gate to investigate mechanisms at the individual particle level using spectroscopy and microscopy techniques.