ELECTROCHEMISTRY OF CHEMICALLY LITHIATED NAV3O8 - A POSITIVE ELECTRODE MATERIAL FOR USE IN RECHARGEABLE LITHIUM-ION BATTERIES

Monoclinic NaV3O8 was prepared via aqueous precipitation and subsequen tly chemically lithiated using butyllithium in hexane as lithiation re agent. The topochemical lithiation process leads to materials with var iable Lithium content depending on the lithiation reaction conditions. Up to 3 Li+ mol(-1) could be inserted chemically in the lattice water -free NaV3O8 and result in cleavage of the particles, which leads to h ighly dispersed materials. In contrast to the chemical insertion metho d, almost 3.5 Li+ mol(-1) could be electrochemically inserted in NaV3O 8, corresponding to a specific charge of about 310 mAh g(-1). About 2. 5 Li+ mol(-1) could be deinserted potentiodynamically in the potential range from 1.5 to 4.0 V vs Li/Li+ from a chemically lithiated materia l with the composition Li3NaV3O8. This corresponds to a specific charg e of about 215 mAh g(-1). In galvanostatic cycling experiments, a spec ific charge of more than 200 mAh g(-1) could be demonstrated for 100 c ycles using this electrode material. The specific charges obtained are independent ol the applied specific current up to 50 mA g(-1) of the oxide. This behavior indicates that the sodium vanadate host material can support high lithium insertion and deinsertion rates, which make t he chemically lithiated form an attractive candidate for lithium-conta ining positive electrode materials in high-power lithium-ion batteries .