Abstract
Development of stable high-voltage (HV), high capacity (HC) cathode oxides is indispensable to enhancing the performance of current high-energy-density (HED) lithium-ion batteries. Overstoichiometric, layered Li- and Mn-rich (LMR) composite oxides are promising materials for HV-HC cathodes for HED batteries; however, their practical use is limited. By probing the crystal structure, magnetic structure, and microstructure of the Li1.2Mn0.55Ni0.15Co0.1O2 LMR oxide, we demonstrate that the oxide loses its pristine chemistry, structure, and composition during the first charge-discharge cycle and that it proceeds through a series of progressive events that introduce impediments on the ion mobility pathways. We discovered i) the presence of tetrahedral Mn3+, interlayer cation intermixing, interface of layered-spinel, and structurally rearranged domains, cation segregation at an HV charged state, and ii) the loss of Li ions, inhomogeneous distribution of Li/Ni, and structurally transformed domains after the first discharge. The results will advance our fundamental understanding of the obstacles related to ion migration pathways in HV-HC cathode systems and will enable us to formulate design rules for use of such materials in high-energy-density electrochemical-energy-storage devices.
Original language | English |
---|---|
Pages (from-to) | 76-84 |
Number of pages | 9 |
Journal | Nano Energy |
Volume | 36 |
DOIs | |
State | Published - Jun 1 2017 |
Funding
This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Energy Efficiency and Renewable Energy Vehicle Technologies Office (VTO) Applied Battery Research (ABR) subprogram (Program Managers: Peter Faguy and David Howell). Part of this research (magnetic measurements) was supported by the DOE Basic Energy Sciences (BES), Materials Sciences and Engineering Division and the TEM experiments by ORNL's CNMS User Facility, which is sponsored by the DOE BES Scientific User Facilities Division. Part of this research was supported by the DOE Basic Energy Sciences, Materials Sciences and Engineering Division; also by ORNL's User Facility at the Spallation Neutron Source, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences. A portion of the APT work was conducted at William R. Willey Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by DOE's office of Biological and Environmental Research as a part of an EMSL funded science theme user project (UP # 48930). Pacific Northwest National Laboratory is operated by Battelle Memorial Institute for the United States Department of Energy under Contract DE-AC05-76RLO1830.
Keywords
- Cathode
- Lithium-ion batteries
- Nano domains
- TEM, Atom probe tomography