Si-doped high-energy Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode with improved capacity for lithium-ion batteries
- PDF / 651,930 Bytes
- 10 Pages / 584.957 x 782.986 pts Page_size
- 77 Downloads / 166 Views
ARTICLE Si-doped high-energy Li1.2Mn0.54Ni0.13Co0.13O2 cathode with improved capacity for lithium-ion batteries Leah Nation School of Engineering, Brown University, Providence, Rhode Island 02912, USA
Yan Wua) Global Research and Development, General Motors, Warren, Michigan 48092, USA
Christine James and Yue Qi Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, USA
Bob R. Powell Global Research and Development, General Motors, Warren, Michigan 48092, USA
Brian W. Sheldonb) School of Engineering, Brown University, Providence, Rhode Island 02912, USA (Received 15 June 2018; accepted 21 September 2018)
Li[Lix/3Mn2x/3M1 x]O2 (M 5 Ni, Mn, Co) (HE-NMC) materials, which can be expressed as a combination of trigonal LiTMO2 (TM 5 transition metal) and monoclinic Li2MnO3 phases, are of great interest as high capacity cathodes for lithium-ion batteries. However, structural stability prevents their commercial adoption. To address this, Si doping was applied, resulting in improved stability. Raman and differential capacity analyses suggest that silicon doping improves the structural stability during electrochemical cycling. Furthermore, the doped material exhibits a 10% higher capacity relative to the control. The superior capacity likely results from the increased lattice parameters as determined by X-ray diffraction (XRD) and the lower resistance during the first cycle found by impedance and direct current resistance (DCR) measurements. Density functional theory (DFT) predictions suggest that the observed lattice expansion is an indication of increased oxygen vacancy concentration and may be due to the Si doping.
I. INTRODUCTION
The application of lithium-ion batteries for battery electric vehicles (BEV) requires high energy density, low cost, long life, and absolute safety. The cathode is a critical component of the battery because it is the limiting factor with respect to cell energy density and hence a major determinant of the mass, volume, and cost of the battery. Lithium-rich layered oxides Li[Lix/3Mn2x/ x) 3M1 x]O2, alternatively designated as xLi2MnO3–(1 LiMO2 (M 5 Ni, Mn, Co) or HE-NMC, are attractive candidates as cathodes for lithium-ion batteries because they exhibit higher capacity (.250 mA h/g) and lower cost than commercially available cathode materials.1 The high capacity of HE-NMC cathode materials is attributed to oxygen anion participation in redox reactions in addition to transition metal ions.2 In spite of the high capacity of HE-NMC, there are fundamental challenges preventing its commercial application. These include
Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2018.378 J. Mater. Res., 2018
voltage decay during cycling,3 short calendar and cycle life,4 and fast resistance rise at low state of charge (SOC).5 These challenges are closely related to the Mn-rich nature and the structural instability of these materials induced by the loss of oxygen. Consider
Data Loading...
