Sj. Wen et al., FTIR SPECTROSCOPY OF METAL-OXIDE INSERTION ELECTRODES - A NEW DIAGNOSTIC-TOOL FOR ANALYSIS OF CAPACITY FADING IN SECONDARY LI LIMN2O4 CELLS/, Journal of the Electrochemical Society, 143(6), 1996, pp. 136-138
Fourier transform infrared spectroscopy (FTIR) has been applied to the
study of oxide insertion compounds used in rechargeable lithium batte
ries. The mechanisms responsible for capacity fading during normal cyc
ling of LiMn2O4 cells in both the 3 and 4 V regions were determined by
examination of spectra obtained from electrodes following 25 cycles a
t charge and discharge rates of C/6. In the 3 V region, electroactive
material becomes electronically disconnected from the rest of the elec
trode due to fracture of the oxide particles and/or expansion and cont
raction of the active material during the cubic-to-tetragonal phase tr
ansformation. In the upper voltage region, the active electrode materi
al is gradually converted to a lower voltage defect spinel phase via d
issolution of manganese in the electrolyte.