Microemulsion Concentration in Preparation of LiMn2O4 Submicron Spherical Particles as Cathode Materials for Highly Reversible Lithium‐Ion Batteries

Abstract

AbstractSpinel LiMn2O4 is one of the most important cathode materials but it still suffers from rapid capacity degradation during electrochemical cycling. Beside surface coating to improve the electrochemical performances, controlling the bulk morphology of LiMn2O4 (LMO) is another effective strategy. In this work, porous LiMn2O4 microspheres composed of numerous primary nanoparticles are synthesized by micro‐emulsion and co‐precipitation methods. The porous structure and the primary nanoparticles size of LiMn2O4 are effected by the concentration of micro‐emulsion and the precursor of Mn2+. The well‐established porous LiMn2O4 microspheres with abundant ionic channels and good contact with electrolyte endow the spinel a remarkable electrochemical performance. After 300 cycles, 0.50 M‐LMO sample presents excellent reversible capacity of 112.8 mAh g−1 at 0.5 C rate. After 1000 cycles, 0.50 M‐LMO sample presents the highest capacity of 97.9 mAh g−1 and remains 54.2 mAh g−1 at the current rate of 10 C. The porous spherical structure of cathode materials is essential to improve the rate performance due to the good contact between the active material and electrolyte.