Structural Characteristics and Electrochemical Properties of Co-doped Spinel Li1+xCoyMn2-x-yO4 for Lithium-ion Batteries
Li1+xCoyMn2-x-yO4的结构及电化学性能研究

Cobalt was doped into the host spinel to produce cobalt-doped spinel material by a solution technique. The end Co-doped materials have many advantages of narrowly distributed and well crystallized particles and small surface area. The determination of XRD patterns shows that the peaks shift towards high angle and become sharp as the introduction of cobalt. The analysis of infrared (IR) spectroscopy illustrates that cobalt doping can enhance the strength of Mn-O bonds and improve the structural stability of the materials. The presence of cobalt reduces the dissolution of Mn into the electrolyte according to the investigation of ICP analysis results since Co-doped materials have more stable structure and smaller surface area. Cobalt doping can enhance the bond Mn-O and weaken the bond Li-O in the spinel. As the result, the Li+ ion has easier diffusion in the spinel and the Co-doped material has smaller charge-transfer resistant (Rct)- The measurement of electorchemical properties shows that the Co-doped material Li1.03 Co0.05Mn1.92O4 prepared in this technique has good cycling performance and high initial capacity.