Abstract
Li2MnO3 is known to be electrochemically inactive due to Mn in tetravalent oxidation state. Several compositions such as Li2MnO3, Li1.5Al0.17MnO3, Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 were synthesized by a sol-gel Pechini method. All the samples were characterized with XRD, Raman, XPS, SEM, Tap density and BET analyzer. XRD patterns indicated the presence of monoclinic phase for pristine Li2MnO3 and mixed monoclinic/spinel phases (Li2 - xMn1 - yAlx + yO3 + z) for Al-substituted Li2MnO3 compounds. The Al substitution seems to occur both at Li and Mn sites, which could explain the presence of spinel phase. XPS analysis for Mn 2p orbital reveals a significant decrease in binding energy for Li1.0Al0.33MnO3 and Li0.5Al0.5MnO3 compounds. Cyclic voltammetry, charge/discharge cycles and electrochemical impedance spectroscopy were also performed. A discharge capacity of 24 mAh g-1 for Li2MnO3, 68 mAh g-1 for Li1.5Al0.17MnO3, 58 mAh g-1 for Li1.0Al0.33MnO3 and 74 mAh g-1 for Li0.5Al0.5MnO3 were obtained. Aluminum substitutions increased the formation of spinel phase which is responsible for cycling.
Original language | English |
---|---|
Pages (from-to) | 13-22 |
Number of pages | 10 |
Journal | Materials Science and Engineering B: Solid-State Materials for Advanced Technology |
Volume | 201 |
DOIs | |
State | Published - Aug 19 2015 |
Funding
Financial support from the NASA-CANM (Grant # NNX08BA48A ), NASA Space Grant (Grant # NNX10AM80H ) and the US Department of Energy (DOE) BATT (Batteries for Advanced Transportation Technology) Program are acknowledged. We thank Dr. James Poston from the National Energy Technology Laboratory for his continual support with characterization measurements. Financial and technical supports by Spallation Neutron Source user facility are sponsored by the Division of Scientific User Facilities , Office of Basic Energy Sciences , US Department of Energy , under contract DE-AC05-00OR22725 with UT-Battelle, LLC, are gratefully acknowledged. Support (MPP) for neutron characterizations was provided by Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, US Department of Energy. Fruitful discussions with Ms. María Abreu-Sepúlveda and Dr. Gurpreet Singh are also acknowledged.
Keywords
- Al substitution
- Energy storage
- LiMnO cathode
- Lithium ion battery