Electrochemical properties and interfacial reactions of LiNi0.5Mn1.5O4−δ nanorods

AbstractLiNi0.5Mn1.5O4−δ which possesses a high voltage of 4.7V vs. Li+/Li and stable structure has been considered as a promising cathode material for high energy Li-ion batteries. In this study, well-crystallized LiNi0.5Mn1.5O4−δ nanorods with diameter of ∼50nm and length of ∼500nm were synthesized by a hydrothermal-solid state process followed by a lithiation reaction. It delivers ∼120mAhg−1 discharge capacity under 30mAg−1 at 3.5–4.9V, and 90mAhg−1 at 150mAg−1. An unstable solid electrolyte interphase (SEI) film with thickness 2–10nm was observed by transmission electron microscopy. The thick and unstable SEI layers are responsible for its low rate performance and low coulombic efficiency during cycling