Synthesis and Electrochemical Performance of Nanosized Multiple-doped LiMn₂O₄ Prepared at Low Temperature for Li-ion Battery

摘要

Undoped and multiple doped Li-Mn spinel cathode materials for Li-ion battrry have been successfullyo synthsized by citric acid sol-gel method at a lower temperature 600 C. The micro-structures for thematerials were charactered by X-ray diffraction (XRD) and scanning electron microscope (SEM). Allthe synthesized materials are pure spinel phase with cubic structure and nano-sized. Theirelectrochemical properties were tested by galvanostatic charge-discharge cycling for the half-cells at at-2 + the current density 0.2 mAcm (equal to about C/3) between 3.0~4.5V (versus. Li/Li ) at roomtemperature. The undoped LiMn2O4 spinel has a high initial discharge specific capacity of 122.5-1 mAh.g and a very high capacity retention of 92.4% after 40 cycles. The good result could be ascribedto its nano-scale size synthesized in lower temperature in a large part. By multiple doping, pure phasespinel Li1.03M0.06Mn1.91O4 (M= Zn0.03Mg0.03,Al0.03Zn0.03, Al0.03Mg0.03,Al0.03Mg0.015Zn0.015) wereobtained. Multiple doping could improve the Li-Mn spinel Li-ion battrry cathode materialsfurthermore. Among the synthesized materials, Li1.03Zn0.03Mg0.03Mn1.91O4 has the highest capacity-1 retention of 97.4% after 40 cycles with an initial discharge specific capacity of 107.5mAh.g .