High capacity lithium-manganese-nickel-oxide composite cathodes with low irreversible capacity loss and good cycle life for lithium ion batteries  

作　　者：Jingwen Zhang Xun Guo Sumei Yao Xinping Qiu 

机构地区：[1]Key Lab of Organic Optoelectronics and Molecular Engineering,Department of Chemistry,Tsinghua University

出　　处：《Science China Chemistry》2016年第11期1479-1485,共7页中国科学（化学英文版）

基　　金：Financial support by the National Basic Research Program of China(2009CB220105);Beijing Natural Science Foundation (2120001)

摘　　要：We report a method to eliminate the irreversible capacity of 0.4Li_2MnO_3·0.6LiNi_(0.5)Mn_(0.5)O_2(Li_(1.17)Ni_(0.25)Mn_(0.583)O_2) by decreasing lithium content to yield integrated layered-spinel structures.XRD patterns,High-resolution TEM image and electrochemical cycling of the materials in lithium cells revealed features consistent with the presence of spinel phase within the materials.When discharged to about 2.8 V,the spinel phase of LiM_2O_4(M=Ni,Mn) can transform to rock-salt phase of Li_2M_2O_4(M=Ni,Mn) during which the tetravalent manganese ions are reduced to an oxidation state of 3.0.So the spinel phase can act as a host to insert back the extracted lithium ions(from the layered matrix) that could not embed back into the layered lattice to eliminate the irreversible capacity loss and increase the discharge capacity.Their electrochemical properties at room temperature showed a high capacity(about 275 mAh g^(-1) at 0.1 C) and exhibited good cycling performance.We report a method to eliminate the irreversible capacity of 0.4Li_2MnO_3·0.6LiNi_（0.5）Mn_（0.5）O_2（Li_（1.17）Ni_（0.25）Mn_（0.583）O_2） by decreasing lithium content to yield integrated layered-spinel structures.XRD patterns,High-resolution TEM image and electrochemical cycling of the materials in lithium cells revealed features consistent with the presence of spinel phase within the materials.When discharged to about 2.8 V,the spinel phase of LiM_2O_4（M=Ni,Mn） can transform to rock-salt phase of Li_2M_2O_4（M=Ni,Mn） during which the tetravalent manganese ions are reduced to an oxidation state of 3.0.So the spinel phase can act as a host to insert back the extracted lithium ions（from the layered matrix） that could not embed back into the layered lattice to eliminate the irreversible capacity loss and increase the discharge capacity.Their electrochemical properties at room temperature showed a high capacity（about 275 mAh g^（-1） at 0.1 C） and exhibited good cycling performance.

关 键 词：Lithium ion electrode composite materials Lithium-rich material spinel phase layered phase 

分 类 号：TM912[电气工程—电力电子与电力传动]