Electrochemical properties of niobium and phosphate doped spherical Li-rich spinel LiMn2O4 synthesized by ion implantation method  

作　　者：Wei Li Gao-Wa Siqin Zhi Zhu Lu Qi Wen-Huai Tian 

机构地区：[1]Department of Materials Physics and Chemistry,School of Materials Science and Engineering,University of Science and Technology,Beijing 100083,China [2]New Energy Materials and Technology Laboratory,Department of Applied Chemistry,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China

出　　处：《Chinese Chemical Letters》2017年第7期1438-1446,共9页中国化学快报（英文版）

基　　金：supported by a grant from the National High Technology Research and Development Program of China(863 Program)(No.2008AA11A102)

摘　　要：Spherical Li-rich lithium manganese oxide（LMO） spinel material was synthesized by an ion implanted method assisted by polyalcohol doped with Niobium and Phosphate simultaneously.The material was characterized by scanning electron microscopy,X-ray diffraction and BET specific surface area analysis.The electrochemical performances were investigated with galvanostatic techniques and cyclic voltammetry.The synthesis process was investigated with TG/DSC.The results show that the lithium ion can be immersed into the pore of manganese dioxide at a low temperature with the ion implanted method.The prepared materials have a higher discharge capacity and better crystallization than those prepared by solid phase method.The doped Nb can improve the capacity of the Li-rich LMO spinel and reinforce the crystal growth along（111） and（400） planes.The crystal grains show circular and smooth morphology,which makes the specific surface area greatly decreased.Phosphate-doped LMO spinel exhibits good high-rate capacity and structure stability.The prepared Li（1.09）Mn（1.87）Nb（0.031）O（3.99）（PO4）（0.021）delivers a discharge capacity of 119mAhg^-1 at 0.2C（1C=148mAg^-1） and 112.8 mAhg^-1 at 10 C,the discharge capacity retention reaches 98% at 1 ℃ after 50 cycles at 25 ℃ and 94% at 55 ℃.Spherical Li-rich lithium manganese oxide（LMO） spinel material was synthesized by an ion implanted method assisted by polyalcohol doped with Niobium and Phosphate simultaneously.The material was characterized by scanning electron microscopy,X-ray diffraction and BET specific surface area analysis.The electrochemical performances were investigated with galvanostatic techniques and cyclic voltammetry.The synthesis process was investigated with TG/DSC.The results show that the lithium ion can be immersed into the pore of manganese dioxide at a low temperature with the ion implanted method.The prepared materials have a higher discharge capacity and better crystallization than those prepared by solid phase method.The doped Nb can improve the capacity of the Li-rich LMO spinel and reinforce the crystal growth along（111） and（400） planes.The crystal grains show circular and smooth morphology,which makes the specific surface area greatly decreased.Phosphate-doped LMO spinel exhibits good high-rate capacity and structure stability.The prepared Li（1.09）Mn（1.87）Nb（0.031）O（3.99）（PO4）（0.021）delivers a discharge capacity of 119mAhg^-1 at 0.2C（1C=148mAg^-1） and 112.8 mAhg^-1 at 10 C,the discharge capacity retention reaches 98% at 1 ℃ after 50 cycles at 25 ℃ and 94% at 55 ℃.

关 键 词：Spinels Ion implantation Li-ion batteries LiMn2O4 Doping 

分 类 号：O614.111[理学—无机化学]