posted on 2016-02-18, 15:12authored byGary M. Koenig, Jiwei Ma, Baris Key, Justin Fink, Ke-Bin Low, Reza Shahbazian-Yassar, Ilias Belharouak
We report the synthesis
of LiFePO4 (LFP) battery materials
where during synthesis the iron has been substituted by up to 10 mol
% with titanium. Analysis of the Ti-substituted materials revealed
that at the substitution levels investigated, the Ti did not form
a solid solution with the LFP, but rather minority phases containing
Ti phosphates were formed and segregated at the nanoscopic scale.
The minority phases were amorphous or not well-crystallized and accepted
Li on first discharge in a lithium half cell, and solid state NMR
spectra were consistent with one of the constituents being LiTi2(PO4)3. The Ti substituted materials
had increased electrochemical capacities and discharge voltages relative
to LFP prepared in an equivalent process, and the ability to accept
Li on first discharge may find utility in using previously inaccessible
capacity in battery cathode formulations and in balancing excess capacity
from high energy cathode materials.