Mitigation of voltage decay in Li-rich layered oxides as cathode materials for lithium-ion batteries

查看全文 作　　者：Wenhui [1]Hu;Youxiang [1,2]Zhang;Ling [1]Zan;Hengjiang [1]Cong

机构地区：[1]College of Chemistry and Molecular Sciences,Wuhan University,Wuhan,430072,China;[2]Shenzhen Research Institute of Wuhan University,Shenzhen,518000,China

出　　处：《Nano Research》索引2020年第13卷第1期,共9页

基　　金：the National Natural Science Foundation of China(No.21271145);the National Science Foundation of Hubei Province(No.2015CFB537);the Science and Technology Innovation Committee of Shenzhen Municipality(No.JCYJ20170306171321438);the financial support for this investigation. 摘　　要：Lithium-rich layered oxides(LLOs)have been extensively studied as cathode materials for lithium-ion batteries(LIBs)by researchers all over the world in the past decades due to their high specific capacities and high charge-discharge voltages.However,as cathode materials LLOs have disadvantages of significant voltage and capacity decays during the charge-discharge cycling.It was shown in the past that fine-tuning of structures and compositions was critical to the performances of this kind of materials.In this report,LLOs with target composition of Li1.17Mn0.50Ni0.24Co0.09O2 were prepared by carbonate co-precipitation method with different pH values.X-ray powder diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscope(TEM),and electrochemical impedance spectroscopies(EIS)were used to investigate the structures and morphologies of the materials and to understand the improvements of their electrochemical performances.With the pH values increased from 7.5 to 8.5,the Li/Ni ratios in the compositions decreased from 5.17 to 4.64,and the initial Coulombic efficiency,cycling stability and average discharge voltages were gained impressively.Especially,the material synthesized at pH=8.5 delivered a reversible discharge capacity of 263 mAhg−1 during the first cycle,with 79.0%initial Coulombic efficiency,at the rate of 0.1 C and a superior capacity retention of 94%after 100 cycles at the rate of 1 C.Furthermore,this material exhibited an initial average discharge voltage of 3.65 V,with a voltage decay of only 0.09 V after 50 charge-discharge cycles.The improved electrochemical performances by varying the pH values in the synthesis process can be explained by the mitigation of layered-to-spinel phase transformation and the reduction of solid-electrolyte interface(SEI)resistance.We hope this work can shed some light on the alleviation of voltage and capacity decay issues of the LLOs cathode materials. 关键词：lithium ion batteries cathode lithium-rich layered oxides voltage decay Li1.17Mn0.50Ni0.24Co0.09O2

相关文献

参考文献（42）
引证文献（3）
耦合文献（0）

参考文献(42)

引证文献(3)

互联网出版许可证新出网证(渝)字10号全国400电话 - 免长途话费

Mitigation of voltage decay in Li-rich layered oxides as cathode materials for lithium-ion batteries

参考文献(42)

引证文献(3)

用户提示