Properties and structure of spinel Li-Mn-O-F compounds for cathode materials of secondary lithium-ion battery

The spinel Li-Mn-O-F compound cathode materials were synthesized by solid-s tate reaction from calculated amounts LiOH .H2O, MnO2(EMD) and LiF. The res ults of the electrochemical test demonstrated that these materials exhibite d excellent electrochemical properties. It's initial capacity is similar to 115 mAh .g(-1) and reversible efficiency is about 100%. After 60 cycles, i ts capacity Is still around 110 mAh .g(-1) with nearly 100% reversible effi ciency. The spinel Li-Mn-OF compound possibly has two structure models: int erstitial model [Li][Mn-x(3+) Mn-2-x(4+)]O4F8, in which the fluorine is loc ated on the interstice of crystal lattice, and substituted model [Li][Mn-x( 3+) Mn-2-x(4+)]O4-deltaFdelta, which the fluorine atom substituted the oxyg en atom. The electrochemical result supports the interstitial model [Li][Mn x3+Mn2-x4+]O4Fdelta.