Preparation and Electrochemical Properties of High‐Voltage Spinel LiNi0.5Mn1.5O4 Synthesized by using Different Manganese Sources

Abstract

AbstractThe crystal structure and electrochemical performance of the 4.7 V cathode LiNi0.5Mn1.5O4 (LNMO) are quite dependent on the amount of Mn3+ and ordering of Ni/Mn in the octahedral sites. This work attempts to study LNMO synthesized by using different manganese sources, in which the valence states of manganese are +2, +2/+3, +3 and +4. A small amount of Mn3+ existing in the spinel crystal structures of the obtained LNMO can dramatically affect the material's conductivity and electrochemical performance. Among the four studied samples, LNMO‐1 (with MnCO3 as the manganese source) delivers the highest specific capacity of 138 mAh g−1, higher than LNMO‐2 (Mn3O4 as the manganese source), LNMO‐3 (Mn2O3 as the manganese source), and LNMO‐4 (MnO2 as the manganese source). After 100 cycles at 0.2 C, LNMO‐1 still delivers the highest discharge capacity of 129 mAh g−1. This work provides an insight into the phenomenon of how manganese sources influence the lithium diffusion ability and crystal structure stability of LNMO as a cathode material for highly reversible lithium storage.