TY - JOUR AU - Jakes, Peter AU - Granwehr, Josef AU - Kungl, Hans AU - Eichel, Rüdiger-A. TI - Mixed Ionic–Electronic Conducting Li4Ti5O12 as Anode Material for Lithium Ion Batteries with Enhanced Rate Capability – Impact of Oxygen Non-Stoichiometry and Aliovalent Mg2+-Doping Studied by Electron Paramagnetic Resonance JO - Zeitschrift für physikalische Chemie VL - 229 IS - 9 SN - 2196-7156 CY - Berlin PB - De @Gruyter M1 - FZJ-2015-06219 SP - 1439-1450 PY - 2015 AB - Spinel-type Li4Ti5O12 is an attractive anode material for lithium-ion battery applications owing to its high specific energy and almost vanishing mechanical strain upon Li-(de)intercalation. The impact of oxygen non-stoichiometry and aliovalent Mg-doping on the defect chemistry of Li4Ti5O12 has been characterized by quantitative electron paramagnetic resonance (EPR) spectroscopy. The results obtained demonstrate that the Mg2+-ions are amphoterically incorporated at the here studied concentrations on both lithium (MgLi•) and titanium (Mg′′Ti) sites. Mg2+-doping thus simultaneously results in the formation of donor (MgLi•) and acceptor (Mg′′Ti) centers. Furthermore, upon both oxygen deficiency and Mg2+-doping, the concentration of `polaronic'-type Ti3+-states is increased, accounting for the enhanced electronic conductivity. LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000363494500014 DO - DOI:10.1515/zpch-2015-0618 UR - https://juser.fz-juelich.de/record/256252 ER -