Crystal Chemistry of the Olivine-Type Li(Mn[sub y]Fe[sub 1−y])PO[sub 4] and (Mn[sub y]Fe[sub 1−y])PO[sub 4] as Possible 4 V Cathode Materials for Lithium Batteries

A potential 4 V cathode material for lithium batteries was investigated. The crystal chemistry of the olivine-type of (discharged state) and its delithiated form (charged state) were comparatively studied using X-ray diffraction, Mössbauer spectroscopy, and ab initio calculations. A strong oxidizer, nitronium tetrafluoroborate, was used for chemical delithiation of to obtain The strong electron/lattice interaction induced by the trivalent manganese in (charged state) is highlighted as the intrinsic obstacle to generating the full theoretical capacity (ca. 170 mAh/g) of the Mn-rich phase followed by an efficient cathode performance of the optimized © 2001 The Electrochemical Society. All rights reserved.