Synthesis, structure and electrochemical lithium intercalation chemistry of ramsdellite-type LiCrTiO4

LiCrTiO4, which crystallizes in the orthorhombic ramsdellite structure, has been obtained by heating spinel LiCrTiO4 at 1250 degrees C in air. The refined cell parameters are a = 4.9835(6) angstrom b = 9.5095(8) angstrom and c = 2.9282(2) angstrom, space group Pbnm, as determined from Rietveld refinement of X-ray powder diffraction data. The intercalation chemistry of LiCrTiO4 has been investigated. Lithium can be extracted from LiCrTiO4 due to oxidation of Cr-III. at rather high potential 4 V On the other hand, lithium intercalation proceeds readily at 1.5 V due to the reduction of tetravalent titanium. Regarding practical applications, as an electrode for lithium rechargeable batteries, specific capacities of 100 and 120 mAh . g (- 1) are developed at 0.1 mA.cm (- 1), respectively. These findings point out that the ramsdellite form of LiCrTiO4 may be an ambivalent electrode, which can be used either as the positive electrode or the negative electrode of a lithium ion rechargeable battery.